As filed with the Securities and Exchange Commission on May 5, 2026

Registration No. 333-294103

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

PRE-EFFECTIVE AMENDMENT NO. 2

TO THE

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Columbia Financial, Inc.

and

Columbia Bank Savings and Investment Plan

(Exact name of registrant as specified in its charter)

Maryland

6035

42-1991301

State or other jurisdiction of

incorporation or organization

(Primary Standard Industrial

Classification Code Number)

(IRS Employer

Identification No.)

19-01 Route 208 North

Fair Lawn, New Jersey 07410

(800) 522-4167

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Thomas J. Kemly

President and Chief Executive Officer

Columbia Financial, Inc.

19-01 Route 208 North

Fair Lawn, New Jersey 07410

(800) 522-4167

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Christina M. Gattuso, Esq.

Stephen F. Donahoe, Esq.

Kilpatrick Townsend & Stockton LLP

701 Pennsylvania Avenue, NW, Suite 200

Washington, DC 20004

(202) 508-5800

Michael K. Krebs, Esq.

Kathleen R. Henry, Esq.

Nutter McClennen & Fish LLP

155 Seaport Boulevard

Boston, Massachusetts 02210

(617) 439-2000

Approximate date of commencement of proposed sale to the public: As soon as practicable after this Registration Statement becomes effective.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box. ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act: ☐

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to Section 8(a), may determine.

PROSPECTUS

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(Proposed New Holding Company for Columbia Bank)

Up to 192,625,000 Shares of Common Stock

Columbia Financial, Inc., a newly formed Maryland corporation (referred to herein as “Columbia Financial, Inc.”), is offering common stock for sale in connection with the conversion of Columbia Bank MHC from the mutual holding company form of organization to the stock form of organization.

We are offering up to 192,625,000 shares of common stock for sale on a best efforts basis, subject to certain conditions. We must sell a minimum of 142,375,000 shares to complete the offering. All shares are offered at a price of $10.00 per share. Purchasers will not pay a commission to purchase shares of common stock in the offering. Most of the terms of this offering are required by regulations of the Board of Governors of the Federal Reserve System (which we refer to as the “Federal Reserve Board”), including the amount of capital being raised, which is based on an independent appraisal (sometimes referred to herein as “independent appraisal” or “independent valuation”) of Columbia Financial, Inc.

The shares we are offering represent the 73.1% ownership interest in Columbia Financial, Inc., a Delaware corporation (referred to herein as “Columbia Financial”) now owned by Columbia Bank MHC. The remaining 26.9% interest in Columbia Financial currently owned by the public will be exchanged for shares of common stock of Columbia Financial, Inc. The 28,126,427 shares of Columbia Financial currently owned by the public will be exchanged for between 1.8729 shares and 2.5340 shares of common stock of Columbia Financial, Inc. depending on the final independent appraisal of the pro forma market value of Columbia Financial. Columbia Financial and Columbia Bank MHC will cease to exist upon completion of the conversion and Columbia Financial, Inc. will succeed them.

Columbia Financial’s common stock is currently listed on the Nasdaq Global Select Market under the trading symbol “CLBK.” We expect the shares of Columbia Financial, Inc. common stock will continue to be listed on the Nasdaq Global Select Market under the symbol “CLBK” upon the completion of the conversion.

The shares of common stock are first being offered in a subscription offering to eligible depositors and borrowers of Columbia Bank and the tax-qualified employee stock ownership plan of Columbia Bank. Shares of common stock not purchased in the subscription offering may be offered for sale to the general public in a community offering, with a preference first given to natural persons residing in Bergen, Burlington, Camden, Essex, Gloucester, Middlesex, Monmouth, Morris, Passaic, Somerset and Union Counties in New Jersey and then to existing stockholders of Columbia Financial (other than Columbia Bank MHC) and to the general public. We are also offering shares of common stock not subscribed for in the subscription offering and community offering, if any, in a firm commitment underwritten offering.

Immediately after completion of the conversion and offering, we expect to acquire Northfield Bancorp, Inc., the holding company for Northfield Bank, for approximately $597.1 million in a combination of stock and cash (referred to herein as the Northfield Bancorp “merger” or “acquisition”). We expect to pay no more than $179.1 million in cash and issue approximately 41,800,140 shares of common stock at the midpoint of the offering range to Northfield Bancorp’s stockholders in exchange for their shares of Northfield Bancorp common stock, assuming that 70% of Northfield Bancorp’s outstanding shares of common stock are exchanged for shares of Columbia Financial, Inc. common stock and 30% of Northfield Bancorp’s outstanding shares of common stock are exchanged for cash in the merger. This will represent approximately 15.4% of the outstanding common stock of Columbia Financial, Inc. at the midpoint of the offering range.

If we do not receive orders for at least 142,375,000 shares of common stock, the 41,800,140 shares we issue to stockholders of Northfield Bancorp in connection with our acquisition of Northfield Bancorp can be counted to reach the minimum number of shares required to be sold in the offering. In that scenario, the minimum number of shares that Columbia Financial, Inc. must sell for cash in the offering is 100,574,860 shares. The number of shares that we issue to Northfield Bancorp stockholders, and therefore the number of shares that we must sell for cash to reach the minimum of the offering range, will vary depending on market conditions and the percentage of the merger consideration that Northfield Bancorp stockholders elect to receive in stock rather than cash.

(continued on following page)

OFFERING SUMMARY

Price: $10.00 Per Share


	Adjusted Minimum		Minimum		Midpoint		Maximum
Number of shares offered for sale		142,375,000		142,375,000		167,500,000		192,625,000
Gross offering proceeds	$	1,423,750,000	$	1,423,750,000	$	1,675,000,000	$	1,926,250,000
Estimated offering expenses, excluding underwriters’ fees	$	8,450,000	$	8,450,000	$	8,450,000	$	8,450,000
Estimated underwriters’ fees and commissions⁽¹⁾	$	31,329,139	$	27,861,000	$	30,172,500	$	34,619,625
Estimated net proceeds	$	1,383,970,861	$	1,387,439,000	$	1,636,377,500	$	1,883,180,375
Estimated net proceeds per share	$	9.72	$	9.74	$	9.77	$	9.78

(1)

Assumes that 65% of the shares are sold in the subscription offering, 5% are sold in the community offering other than at the adjusted minimum, 30% of the shares will be sold in the firm commitment underwritten offering and 41,800,140 shares are issued in connection with our anticipated merger with Northfield Bancorp, Inc at the adjusted minimum as part of the community offering. See “The Conversion and Offering — Plan of Distribution; Selling Agent and Underwriter Compensation” for information regarding the compensation to be received by Keefe, Bruyette & Woods, Inc. in the subscription and community offerings and compensation to be received by Keefe, Bruyette & Woods, Inc. and the other broker-dealers in the firm commitment underwritten offering.

This investment involves a degree of risk, including the possible loss of principal. Please read “Risk Factors” beginning on page 18.

These securities are not deposits or accounts and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. None of the Securities and Exchange Commission, the Board of Governors of the Federal Reserve System, the Office of the Comptroller of the Currency, the Federal Deposit Insurance Corporation, nor any state securities regulator has approved or disapproved of these securities or determined if this prospectus is accurate or complete. Any representation to the contrary is a criminal offense.

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For assistance, please contact the Stock Information Center at [●]

The date of this prospectus is [●], 2026

(continued from cover)

The following table shows the net cash proceeds of the offering and merger at the adjusted minimum, the minimum, the midpoint and the maximum assuming 41,800,140 shares are issued to stockholders of Northfield Bancorp, Inc. at the adjusted minimum.


	Adjusted Minimum			Minimum			Midpoint			Maximum
Net offering proceeds	$	1,383,970,861		$	1,387,439,000		$	1,636,377,500		$	1,883,180,375
Less: merger shares used to complete offering	$	(418,001,000	)	$	—		$	—		$	—
Less: cash merger consideration paid to Northfield Bancorp	$	(179,143,000	)	$	(179,143,000	)	$	(179,143,000	)	$	(184,172,000	)
Less: common stock acquired by employee stock ownership plan	$	(42,713,000	)	$	(42,713,000	)	$	(50,250,000	)	$	(57,788,000	)
Net cash proceeds of offering	$	744,113,861		$	1,165,583,000		$	1,406,984,500		$	1,641,220,375

The minimum order is 25 shares. The subscription offering will end at 2:00 p.m., Eastern time, on June 16, 2026. The community offering, if held, may continue without notice to you until July 31, 2026 or longer if the Federal Reserve Board approves a later date. No single extension may exceed 90 days and the offering must be completed by June 29, 2028. Once submitted, orders are irrevocable unless the offering is terminated or extended beyond July 31, 2026, or the number of shares of common stock to be sold is increased to more than 192,625,000 shares or decreased to less than 142,375,000 shares. If we extend the offering beyond July 31, 2026, all subscribers will be notified and given the opportunity to confirm, change or cancel their orders. If you do not respond to this notice, we will promptly return your funds with interest calculated at Columbia Bank’s statement savings rate or cancel your deposit account withdrawal authorization. If we intend to sell fewer than 142,375,000 shares or more than 192,625,000 shares, we will promptly return all funds and set a new offering range. All subscribers will be resolicited and given the opportunity to place a new order. Funds received before the completion of the subscription and community offerings will be held in a segregated account at Columbia Bank and will earn interest at Columbia Bank’s statement savings rate, which is currently 0.40% per annum.

Keefe, Bruyette & Woods, Inc., A Stifel Company, will assist us in selling the shares on a best efforts basis in the subscription and community offerings. Keefe, Bruyette & Woods, Inc. is not required to purchase any shares of common stock offered for sale in the subscription and community offerings. We will also offer shares of common stock not subscribed for in the subscription and community offerings in a firm commitment underwritten offering. Keefe, Bruyette & Woods, Inc. will act as the lead-left book running manager, Piper Sandler & Co. will act as co-book running manager and Brean Capital, LLC will act as co-manager for the firm commitment underwritten offering.

The completion of the conversion is not contingent on the acquisition of Northfield Bancorp. In the event that the merger is terminated, Columbia Financial will either terminate the conversion or delay the conversion in order to amend this prospectus. If we determine to delay the conversion, the timing and manner of the conversion would be subject to significant modification and subscribers would have the right to modify or rescind their purchase orders. In the event that the acquisition is terminated and we determine to proceed with the conversion, subscribers would have the opportunity to modify or rescind their purchase orders. In the event we determine to terminate the conversion and offering, we will promptly return your funds with interest calculated at Columbia Bank’s statement savings rate and all deposit account withdrawal authorizations will be cancelled.

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TABLE OF CONTENTS


	Page
Summary		1
Risk Factors		18
A Warning About Forward-Looking Statements		37
Selected Consolidated Financial and Other Data of Columbia Financial and Subsidiaries		39
Selected Consolidated Financial and Other Data of Northfield Bancorp and Subsidiaries		41
Recent Developments of Columbia Financial		43
Recent Developments of Northfield Bancorp		47
How We Intend to Use the Proceeds of the Offering		52
Our Dividend Policy		53
Market for the Common Stock		54
Historical and Pro Forma Regulatory Capital Compliance		55
Pro Forma Unaudited Condensed Consolidated Financial Statements Giving Effect to the Conversion and Proposed Merger		58
Capitalization		65
Pro Forma Data		67
The Acquisition of Northfield Bancorp		72
Business of Columbia Financial and Columbia Bank		77
Management’s Discussion and Analysis of Financial Condition and Results of Operations of Columbia Financial		90
Business of Northfield Bancorp and Northfield Bank		120
Management’s Discussion and Analysis of Financial Condition and Results of Operations of Northfield Bancorp		138
Regulation and Supervision		156
Management of Columbia Financial, Inc.		163
Stock Ownership		199
Subscriptions by Executive Officers and Directors		201
Federal and State Taxation		202
The Conversion and Offering		203
Comparison of Stockholders’ Rights		222
Restrictions on Acquisition of Columbia Financial, Inc.		228
Description of Columbia Financial, Inc. Capital Stock		230
Transfer Agent and Registrar		231
Registration Requirements		231
Legal and Tax Opinions		231
Experts		232
Where You Can Find More Information		232
Index to Consolidated Financial Statements of Columbia Financial, Inc.		F-1
Index to Consolidated Financial Statements of Northfield Bancorp, Inc.		F-79

SUMMARY

The following summary explains the significant aspects of the conversion, the offering and the exchange of existing shares of Columbia Financial common stock for shares of Columbia Financial, Inc. common stock and our proposed acquisition of Northfield Bancorp. It may not contain all of the information that is important to you. Before making an investment decision, you should read this entire document carefully, including the consolidated financial statements and the notes thereto for both Columbia Financial and Northfield Bancorp, and the section entitled “Risk Factors.”

In this prospectus, the terms “we,” “us” and “our” refer to Columbia Financial and its consolidated subsidiaries or its successor Columbia Financial, Inc., Columbia Bank MHC and Columbia Bank unless the context requires otherwise.

Our Companies

Columbia Financial, Inc.

The shares being offered will be issued by Columbia Financial, Inc. (referred to herein as “Columbia Financial, Inc.”), a newly formed Maryland corporation. Following the completion of the conversion and offering, Columbia Financial, Inc. will become the publicly-traded savings and loan holding company for Columbia Bank. The shares of Columbia Financial, Inc.’s common stock are expected to trade on the Nasdaq Global Select Market under the symbol “CLBK” upon the completion of the conversion.

Columbia Bank MHC

Columbia Bank MHC was organized in 1997 under the laws of the United States. In connection with the reorganization, Columbia Financial became the wholly-owned subsidiary of Columbia Bank MHC. Columbia Bank MHC’s principal business activity is the ownership of 76,016,524 shares of common stock, or 73.1% of the issued and outstanding shares of Columbia Financial as of December 31, 2025.

Columbia Financial

Columbia Financial (referred to herein as “Columbia Financial”) is a Delaware corporation that was organized in 1997 in connection with the mutual holding company reorganization of Columbia Bank. Columbia Financial is the holding company of Columbia Bank, which is a federally chartered stock savings bank. In 2018, Columbia Financial conducted a minority stock offering and sold 43% of its shares of common stock, for gross proceeds of $498.3 million, in a subscription offering to the depositors of Columbia Bank with the remaining shares issued to Columbia Bank MHC.

Columbia Bank

Columbia Bank is a federally chartered savings bank founded in 1927. Columbia Bank has elected and has received regulatory approval to operate as a “covered savings association” pursuant to the Home Owners’ Loan Act, as amended, and the regulations of the Office of the Comptroller of the Currency (the “OCC”) promulgated thereunder. A covered savings association generally has the same rights and privileges as a national bank, and is subject to the same duties, restrictions, penalties, liabilities, conditions, and limitations that would apply to a national bank. Management believes that the key benefits of Columbia Bank’s election to operate as a covered savings association include the elimination of the requirement to meet the qualified thrift lender test and that Columbia Bank is no longer subject to the limits on an aggregate amount of commercial loans that are applicable to savings associations.

We serve the financial needs of our depositors and the local community as a community-minded, customer service-focused institution. We offer traditional financial services to businesses and consumers in our market areas. We attract deposits from the general public and use those funds to originate a variety of loans, including multifamily and commercial real estate loans, commercial business loans, one-to-four family real estate loans, construction loans, home equity loans and advances, and other consumer loans. We offer title insurance through our wholly-owned subsidiary, First Jersey Title Services, Inc. In addition, Columbia Insurance Services, Inc., a wholly-owned subsidiary of Columbia Bank, is a full-service insurance agency that offers a broad range of insurance products, including personal and business lines of insurance, to our customers and primarily New Jersey residents. We also offer wealth management services through a third-party relationship.

Our executive offices are located at 19-01 Route 208 North, Fair Lawn, New Jersey 07410 and our telephone number is (800) 522-4167. Our website address is www.columbiabankonline.com. Information on our website should not be considered a part of this prospectus.

Our Acquisition History

Mergers and acquisitions have historically been a component of our business model and growth strategy. In addition to our currently proposed merger with Northfield Bancorp, since November 2019, we have acquired Atlantic Stewardship Bank, Roselle Bank, Freehold Bank and RSI Bank. For more information, see “Business of Columbia Financial and Columbia Bank — Acquisition History.”

Northfield Bancorp, Inc. Acquisition

We are conducting the conversion and offering under the terms of our plan of conversion and reorganization that we adopted on January 31, 2026 (which is referred to in this prospectus as the “plan of conversion”). Concurrently with our adoption of the plan of conversion and reorganization, we also entered into an Agreement and Plan of Merger (referred to herein as the “merger agreement”) to acquire Northfield Bancorp, Inc. (referred to herein as “Northfield Bancorp”). As of December 31, 2025, Northfield Bancorp had consolidated assets of $5.8 billion, deposits of $4.0 billion and stockholders’ equity of $690.1 million. Northfield Bancorp is the parent holding company for Northfield Bank. Northfield Bank, founded in 1887, operates 37 full-service banking offices in Staten Island and Brooklyn, New York, and Hunterdon, Middlesex, Mercer, and Union counties, New Jersey.

Under the merger agreement, Northfield Bancorp will merge into Columbia Financial, Inc. immediately following the completion of the conversion, with Columbia Financial, Inc. as the surviving entity, and Northfield Bank will merge with and into Columbia Bank, with Columbia Bank as the surviving entity. The acquisition of Northfield will expand our presence in our existing markets and will provide us with immediate entry into Staten Island and Brooklyn, where Northfield had a combined deposit base of $2.1 billion as of December 31, 2025.

In connection with the merger of Northfield Bancorp into Columbia Financial, Inc., each share of Northfield Bancorp common stock outstanding immediately prior to the closing date of the merger will be converted, at the election of Northfield Bancorp stockholders, as follows: (i) if the final independent valuation, immediately prior to the completion of the conversion (the “final independent valuation”) is less than $2.3 billion, 1.425 shares of Columbia Financial, Inc. common stock (the “merger exchange ratio”) or $14.25 in cash (the “per share cash consideration”); (ii) if the final independent valuation is equal to or greater than $2.3 billion and less than $2.6 billion, the merger exchange ratio will be increased to 1.450 shares of Columbia Financial, Inc. common stock and the per share cash consideration will be increased to $14.50; or (iii) if the final independent valuation is greater than $2.6 billion, the merger exchange ratio will be increased to 1.465 shares of Columbia Financial, Inc. common stock and the per share cash consideration will be increased to $14.65. The “final independent valuation” is also sometimes referred to herein as the “appraised full conversion value.” No more than 30% of the shares of Northfield Bancorp common stock issued and outstanding as of the closing of the merger will be converted into cash.

The acquisition of Northfield Bancorp is contingent upon the completion of the conversion. The merger is subject to approval by the stockholders of Columbia Financial and Northfield Bancorp. The merger is also subject to the receipt of the approvals of the Board of Governors of the Federal Reserve System (the “Federal Reserve Board”) and the OCC. We anticipate simultaneously completing the conversion, the offering and the merger early in the third quarter of 2026, although no assurance can be given that we will be able to complete these transactions by that date or at all.

The completion of the conversion is not contingent on the acquisition of Northfield Bancorp. In the event that the merger is terminated, Columbia Financial will either terminate the conversion or delay the conversion in order to amend this prospectus. If the merger is terminated and we determine to terminate the conversion and offering, we will promptly return your funds with interest calculated at Columbia Bank’s statement savings rate and all deposit account withdrawal authorizations will be cancelled. In the event we determined to proceed with the conversion and offering without the acquisition, the timing and manner of the conversion would be subject to significant modifications including an updated appraisal valuation and business plan given we would be undertaking the conversion on a stand-alone basis.

Post-Acquisition Business Strategy

Our business strategy is to continue to operate and grow a profitable community-oriented financial institution. We plan to achieve this by executing our strategy of:

•

Increasing our earnings by growing our balance sheet with increased emphasis on commercial business lending and core deposits;

•

Employing a stockholder-focused management of capital;

•

Expanding our franchise through de novo branching, branch acquisitions and the possible acquisition of other financial institutions and/or financial services companies;

•

Maintaining asset quality through the application of a prudent, disciplined approach to credit risk as part of an overall risk management program;

•

Enhancing our technology infrastructure to broaden our product capabilities and improve product delivery and efficiency;

•

Focusing on an enhanced customer experience and continued customer satisfaction; and

•

Increasing fee income through continued growth of fee-based activities.

For more information on our post-acquisition business strategy, see “The Acquisition of Northfield Bancorp — Post-Acquisition Business Strategy.”

Description of the Conversion

Columbia Bank has been organized in the mutual holding company structure since 1997. The following diagram shows our current organizational structure, reflecting ownership percentages as of December 31, 2025:

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The “second-step” conversion process that we are now undertaking involves a series of transactions by which we will convert our organization from the partially public mutual holding company form to the fully public stock holding company structure. In the stock holding company structure, all of Columbia Bank’s common stock will be owned by Columbia Financial, Inc. and all of Columbia Financial, Inc.’s common stock will be owned by the public. Upon completion of the conversion and offering, Columbia Financial and Columbia Bank MHC will cease to exist.

As part of the conversion, we are offering for sale shares of common stock representing the 73.1% ownership interest of Columbia Financial that is currently held by Columbia Bank MHC. At the conclusion of the conversion and offering, existing public stockholders of Columbia Financial will receive shares of common stock of Columbia Financial, Inc. in exchange for their existing shares of common stock of Columbia Financial, based upon an exchange ratio of 1.8729 to 2.5340 at the minimum and maximum of the offering range, respectively. The actual exchange ratio will be determined at the conclusion of the conversion and the offering based on the total number of shares sold in the offering and is intended to result in Columbia Financial’s existing public stockholders owning approximately the

same percentage interest, 26.9% of Columbia Financial, Inc. common stock as they currently own of Columbia Financial common stock, without giving effect to cash paid in lieu of issuing fractional shares or shares that existing stockholders may purchase in the offering or shares issued in the Northfield Bancorp acquisition. For more information, see “— The Exchange of Existing Shares of Columbia Financial Common Stock.”

After the conversion and offering, and completion of the merger, our ownership structure will be as follows:

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The normal business operations of Columbia Bank will continue without interruption during the conversion and offering. The executive officers and the directors who will serve on the boards of directors of Columbia Financial and Columbia Bank following Columbia Financial’s 2026 annual meeting of stockholders will serve as executive officers and directors of Columbia Financial, Inc. and Columbia Bank following completion of the conversion.

Immediately following the completion of the conversion, Northfield Bancorp will merge with and into Columbia Financial, Inc. and Northfield Bank will merge with and into Columbia Bank. Prior to the effective time of the merger, Columbia Financial, Inc. will increase the size of its board of directors by four members (to 13 directors). As of the effective time of the merger, the board of directors of Columbia Financial, Inc. will be comprised of the nine legacy Columbia Financial directors and four members of the Northfield Bancorp board of directors selected by Columbia Financial, one of whom shall be Steven M. Klein. In addition, at the effective time of the merger, Steven M. Klein will serve as Senior Executive Vice President and Chief Operating Officer of Columbia Financial, Inc. and Columbia Bank.

Reasons for the Conversion and Offering

Our primary reasons for the conversion and offering are as follows:

•

Facilitate our acquisition of Northfield Bancorp. The stock holding company structure enables us to acquire Northfield Bancorp through a combination of common stock and cash consideration, which is not possible in our current mutual holding company form of organization.

•

To enhance stockholder returns through higher earnings and more flexible capital management strategies.

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To pay dividends on our common stock. The stock holding company structure will eliminate the current limitations imposed by the mutual holding company structure on dividend payments and make it less costly for us to pay dividends.

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Strengthen our capital position with the additional capital we will raise in the offering to support our planned growth. A strong capital position is essential to achieving our long-term objectives of growing Columbia Bank and building stockholder value. While Columbia Bank exceeds all regulatory capital requirements, the proceeds from the offering will greatly strengthen our capital position and enable us to support our planned growth in accordance with our strategic plan.

•

Transition us to a more familiar and flexible organizational structure. The stock holding company structure is a more familiar form of organization, which we believe will make our common stock more

appealing to investors and enhance the liquidity of our common stock. A more liquid and active market will make it easier for our stockholders to buy and sell our common stock and will give us greater flexibility in implementing capital management strategies. The stock holding company structure will also give us greater flexibility to access the capital markets through possible future equity and debt offerings, although we have no current plans or arrangements for any such offerings.

•

Facilitate future mergers and acquisitions. Although we do not currently have any understandings or agreements regarding any specific acquisition transactions, other than our pending merger with Northfield Bancorp, the stock holding company structure will give us greater flexibility to structure, and make us a more attractive and competitive bidder for, mergers and acquisitions of other financial institutions and/or financial services companies as opportunities arise.

Terms of the Offering

We are offering between 142,375,000 and 192,625,000 shares of common stock in a subscription offering to eligible depositors and borrowers of Columbia Bank and to our tax-qualified plans. Any shares not purchased in the subscription offering may be offered in a community offering to the general public and a firm commitment underwritten offering.

Once submitted, orders are irrevocable unless the offering is terminated or is extended beyond July 31, 2026, or the number of shares of common stock to be sold is increased to more than 192,625,000 shares or decreased to less than 142,375,000 shares. We may terminate the conversion and offering with the concurrence of the Federal Reserve Board. If terminated, orders for common stock already submitted will be canceled, subscribers’ funds will be promptly returned with interest calculated at Columbia Bank’s statement savings rate and all deposit account withdrawal authorizations will be canceled. If we extend the offering beyond July 31, 2026, all subscribers will be notified and given the opportunity to confirm, change or cancel their orders. If you do not respond to this notice, we will promptly return your funds with interest calculated at Columbia Bank’s statement savings rate or cancel your deposit account withdrawal authorization. If we intend to sell fewer than 142,375,000 shares or more than 192,625,000 shares, we will promptly return all funds and set a new offering range. All subscribers will be resolicited and given the opportunity to place a new order.

The purchase price is $10.00 per share. All investors will pay the same purchase price per share. Investors will not be charged a commission to purchase shares of common stock in the offering. Keefe, Bruyette & Woods, Inc., our conversion advisor and marketing agent in the offering, will use its best efforts to assist us in selling shares of our common stock in the subscription and community offering. Keefe, Bruyette & Woods, Inc. is not obligated to purchase any shares of common stock in the subscription offering.

How We Determined the Offering Range and Exchange Ratio

Federal regulations require that the aggregate purchase price of the securities sold in the offering be based upon our estimated pro forma market value after the conversion (i.e., taking into account the expected receipt of proceeds from the sale of securities in the offering), as determined by an independent appraisal. In accordance with the regulations of the Federal Reserve Board, a valuation range is established that ranges from 15% below to 15% above this pro forma market value. We have retained RP Financial, LC. (“RP Financial”), which is experienced in the evaluation and appraisal of financial institutions, to prepare the appraisal. RP Financial has indicated that in its valuation as of February 2, 2026, the pro forma market value of Columbia Financial’s common stock (taking into account the acquisition of Northfield Bancorp) was $2.7 billion, resulting in a range from $2.4 billion at the minimum to $3.1 billion at the maximum. The appraised full conversion value (offering shares and exchange shares) ranges from $1.9 billion to $2.6 billion, with the midpoint of $2.291 billion. Based on this independent valuation of the appraised full conversion value, we are selling the number of shares representing the 73.1% of outstanding Columbia Financial common stock currently owned by Columbia Bank MHC. This results in an offering range of $1.4 billion to $1.9 billion, with a midpoint of $1.7 billion.

RP Financial will receive fees totaling $625,000 for its appraisal report, plus $25,000 for any appraisal updates (of which there will be at least one) and reimbursement of out-of-pocket expenses.

In preparing its appraisal, RP Financial considered the information in this prospectus, including our financial statements. RP Financial also considered the following factors, among others:

•

the trading market for Columbia Financial common stock and securities of comparable institutions and general conditions in the market for such securities;

•

our historical and projected operating results and financial condition and that of Northfield Bancorp, including, but not limited to, net interest income, the amount and volatility of interest income and interest expense relative to changes in market conditions and interest rates, asset quality, levels of loan loss provisions, the amount and sources of non-interest income, and the amount of non-interest expense;

•

the economic, demographic and competitive characteristics of our post-merger market area, including, but not limited to, employment by industry type, unemployment trends, size and growth of the population, trends in household and per capita income, and deposit market share;

•

a comparative evaluation of our pro forma operating and financial statistics with those of other similarly-situated, publicly-traded banks and bank holding companies and savings and loan holding companies, which included a comparative analysis of balance sheet composition, income statement and balance sheet ratios, credit and interest rate risk exposure; and

•

the effect of the capital raised in this offering and the effect of our merger with Northfield Bancorp on our net worth and earnings potential, including, but not limited to, the increase in consolidated equity resulting from the offering, the estimated increase in earnings resulting from the investment of the net proceeds of the offering, and the estimated impact on consolidated equity and earnings resulting from adoption of the proposed employee stock benefit plans.

RP Financial considered adjustments to the pro forma market value based on a comparison of Columbia Financial with a peer group of publicly traded bank holding companies and savings and loan holding companies that RP Financial considered comparable to Columbia Financial under regulatory guidelines applicable to the independent valuation. Under these guidelines, a minimum of ten peer group companies are selected from the universe of all publicly-traded financial institutions with relatively comparable resources, strategies and financial and other operating characteristics. Such companies must also be traded on an exchange (such as Nasdaq or the New York Stock Exchange). The peer group companies selected for Columbia Financial were all fully-converted stock institutions or commercial banks that were not subject to an actual or rumored acquisition and that had been in fully-converted form for at least one year. In addition, RP Financial limited the peer group companies to institutions located in the Mid-Atlantic with assets between $7.0 billion and $25.0 billion, tangible equity-to-assets ratios of greater than 8.0%, and positive core earnings. The peer group companies included companies with:

•

average assets of $12.7 billion;

•

average non-performing assets of 0.54% of total assets;

•

average loans of 75.7% of total assets;

•

average tangible equity of 9.0% of total assets; and

•

average core income of 0.97% of average assets.

The appraisal was based in part upon the financial condition and results of operations, the effect of the additional capital that will be raised from the sale of common stock in this offering and the effect of our merger with Northfield Bancorp and an analysis of a peer group of 12 publicly traded bank and thrift holding companies that RP Financial considered comparable to Columbia Financial. The appraisal peer group consists of the companies listed below. Total assets are as of December 31, 2025.


Company Name and Ticker Symbol	Exchange	Headquarters	Total Assets (in millions)
CNB Financial Corp. (CCNE)	NASDAQ	Clearfield, PA	$	8,396
ConnectOne Bancorp, Inc. (CNOB)	NASDAQ	Englewood Cliffs, NJ	$	14,003
Dime Community Bancshares, Inc. (DCOM)	NASDAQ	Hauppauge, NY	$	15,342
First Commonwealth Financial Corp. (FCF)	NYSE	Indiana, PA	$	12,343
Kearny Financial Corp. (KRNY)	NASDAQ	Fairfield, NJ	$	7,261
NBT Bancorp, Inc. (NBTB)	NASDAQ	Norwich, NY	$	15,995
Peapack-Gladstone Financial Corp. (PGC)	NASDAQ	Bedminster, NJ	$	7,526
Provident Financial Services, Inc. (PFS)	NYSE	Jersey City, NJ	$	24,981
S&T Bancorp, Inc. (STBA)	NASDAQ	Indiana, PA	$	9,871
Tompkins Financial Corporation (TMP)	NYSEAM	Ithaca, NY	$	8,668
Univest Financial Corp. (UVSP)	NASDAQ	Souderton, PA	$	8,437
WSFS Financial Corp. (WSFS)	NASDAQ	Wilmington, DE	$	21,314

RP Financial considered adjustments to the pro forma market value based on a comparison of Columbia Financial with the peer group. RP Financial advised the board of directors that the valuation analysis took into consideration that relative to the peer group a slight downward adjustment was applied for profitability, growth and viability of earnings. Additionally, RP Financial made slight upward adjustments for Columbia Financial’s financial condition and asset growth in comparison to the peer group’s characteristics for those valuation parameters. RP Financial made no adjustments for primary market area, dividends, liquidity of the shares, marketing of the issue, management and the effect of government regulations and regulatory reform.

The downward adjustment applied for profitability, growth and viability of earnings took into consideration Columbia Financial’s lower pro forma core earnings, based on Columbia Financial’s lower pro forma returns on average assets and average equity. The upward adjustment applied for financial condition was due to Columbia Financial’s more favorable credit quality measures and stronger pro forma capital position. The upward adjustment applied for asset growth was due to Columbia Financial’s stronger pro forma asset growth as the result of the acquisition of Northfield Bancorp and greater leverage capacity as the result of the capital that will be raised in the offering.

Four measures that some investors use to analyze whether a stock might be a good investment are the ratios of the offering price to the issuer’s “book value” and “tangible book value” and the ratios of the offering price to the issuer’s earnings and “core earnings.” RP Financial considered these ratios in preparing its appraisal, among other factors. Book value is the same as total equity and represents the difference in value between the issuer’s assets and liabilities. Tangible book value is equal to total equity minus intangible assets. For purposes of the appraisal, core earnings is defined as net earnings after taxes, excluding the after-tax portion of income from non-recurring items.

The following table presents a summary of selected pricing ratios for the peer group companies utilized by RP Financial in its appraisal and the pro forma pricing ratios for us as calculated by RP Financial in its appraisal report, based on financial data as of and for the twelve months ended December 31, 2025. Stock prices are as of February 2, 2026 as reflected in the appraisal report.


	Price to Core Earnings Multiple⁽¹⁾			Price to Book Value Ratio			Price to Tangible Book Value Ratio
Columbia Financial (pro forma):
Adjusted Minimum		18.30	x		79.30	%		85.98	%
Minimum		20.06			82.24			88.03
Midpoint		22.06			87.03			92.76
Maximum		24.04			91.74			97.28
Peer group companies as of February 2, 2026:
Average		12.81	x		107.09	%		136.39	%
Median		12.28			107.53			132.17

(1)	Price to core earnings multiples calculated by RP Financial in the independent appraisal are based on an estimate of “core” or recurring earnings on a trailing twelve-month basis through December 31, 2025. These ratios are different than presented in “Pro Forma Data.”

Compared to the average pricing ratios of the peer group, at the maximum of the offering range, our common stock would be priced at a premium of 87.7% to the peer group on a price-to-core earnings basis, a discount of 14.3% to the peer group on a price-to-book basis and a discount of 28.7% to the peer group on a price-to-tangible book basis. This means that, at the maximum of the offering range, a share of our common stock would be more expensive than the peer group on an earnings basis but less expensive than the peer group on a book value basis and a tangible book value basis.

Compared to the average pricing ratios of the peer group, at the minimum of the offering range, our common stock would be priced at a premium of 56.6% to the peer group on a price-to-core earnings basis, a discount of 23.2% to the peer group on a price-to-book basis and a discount of 35.5% to the peer group on a price-to-tangible book basis. This means that, at the minimum of the offering range, a share of our common stock would be more expensive than the peer group on an earnings basis and less expensive than the peer group on a book value and tangible book value basis.

Our board of directors reviewed RP Financial’s appraisal report, including the methodology and the assumptions used by RP Financial, and determined that the offering range was reasonable and adequate. Our board of directors has

decided to offer the shares for a price of $10.00 per share. The purchase price of $10.00 per share was determined by us, taking into account, among other factors, the market price of our stock before adoption of the plan of conversion, the requirement under Federal Reserve Board regulations that the common stock be offered in a manner that will achieve the widest distribution of the stock, and desired liquidity in the common stock after the offering. Based upon the appraised full conversion value and the offering range, each existing stockholder of Columbia Financial will receive between 1.8729 shares and 2.5340 shares of Columbia Financial, Inc. common stock for each current share of Columbia Financial common stock they own, with 2.2035 shares at the midpoint. Based upon this exchange ratio, we expect to issue between 52,382,845 shares and 70,870,908 shares of Columbia Financial, Inc. common stock to the holders of Columbia Financial common stock outstanding immediately before the completion of the conversion and offering. If we do not receive orders for at least 142,375,000 shares in the subscription and community offerings, then, in Columbia Financial, Inc.’s sole discretion, to complete the offering, up to 41,800,140 of the shares issued to the stockholders of Northfield Bancorp in the community offering, assuming 70% of the merger consideration is paid in stock, can be applied to the minimum number of shares required to complete the offering. If Columbia Financial, Inc. applies the 41,800,140 shares issued to the stockholders of Northfield Bancorp, then the minimum number of shares that Columbia Financial, Inc. must sell for cash in the subscription and community offerings is 100,574,860.

Because of differences in important factors such as operating characteristics, location, financial performance, asset size, capital structure and business prospects between us and other institutions that comprise our peer group, you should not rely on these comparative valuation ratios as an indication as to whether or not our common stock is an appropriate investment for you. The independent appraisal is not intended, and must not be construed, as a recommendation of any kind as to the advisability of purchasing our common stock. The appraisal does not indicate market value. You should not assume or expect that the appraisal described above means that our common stock will trade at or above the $10.00 purchase price after the offering.

Our board of directors makes no recommendation of any kind as to the advisability of purchasing shares of common stock in the offering.

Possible Change in Offering Range

RP Financial will update its independent appraisal before we complete the conversion and offering. If the appraised full conversion value (offering shares and exchange shares) at that time is either below $1.9 billion or above $2.6 billion, then, after consulting with the Federal Reserve Board, we may: terminate the offering and promptly return all funds with interest; set a new offering range and give all subscribers the opportunity to place a new order; or take such other actions as may be permitted by the Federal Reserve Board and the Securities and Exchange Commission.

The Exchange of Existing Shares of Columbia Financial Common Stock

If you are a stockholder of Columbia Financial on the date we complete the conversion and offering, your existing shares will be canceled and exchanged for shares of Columbia Financial, Inc. The number of shares you will receive will be based on an exchange ratio determined as of the completion of the conversion and offering. The following table shows how the exchange ratio will adjust, based on the appraised full conversion value of Columbia Financial as of February 2, 2026, and assuming public stockholders of Columbia Financial own 26.9% of Columbia Financial common stock immediately prior to the completion of the conversion. The table also shows how many shares of Columbia Financial, Inc., a hypothetical owner of Columbia Financial common stock, would receive in the exchange for 100 shares of common stock owned at the completion of the conversion, depending on the number of shares issued in the offering. Information is presented at the adjusted minimum, which reflects the discretionary issuance of shares to Northfield Bancorp stockholders, and at the minimum, midpoint and maximum of the offering range.


	Shares to be Sold in the Offering						Shares to be Exchanged for Existing Shares of Columbia Financial					Total Shares of Common Stock Issued in the Exchange and Sold in the Offering⁽¹⁾		Minority Stockholder Exchange Ratio		Equivalent per Share Value⁽²⁾		Shares to be Received for 100 Existing Shares⁽³⁾
	Amount			Percent			Amount		Percent					Minority Stockholder Exchange Ratio		Equivalent per Share Value⁽²⁾		Shares to be Received for 100 Existing Shares⁽³⁾
Adjusted Minimum		142,375,000	⁽⁴⁾		73.1	%		52,382,845		26.9	%		194,757,845		1.8729	$	18.73		187
Minimum		142,375,000			73.1	%		52,382,845		26.9	%		194,757,845		1.8729	$	18.73		187
Midpoint		167,500,000			73.1	%		61,626,877		26.9	%		229,126,877		2.2035	$	22.04		220
Maximum		192,625,000			73.1	%		70,870,908		26.9	%		263,495,908		2.5340	$	25.34		253

(1)	Represents the appraised full conversion value of Columbia Financial of $1.948 billion at the adjusted minimum and the minimum, $2.291 billion at the midpoint and $2.635 billion at the maximum based on an offering price of $10.00 per share.

(2)	Represents the value of shares of Columbia Financial, Inc. common stock received in the conversion by a holder of one share of Columbia Financial common stock at the exchange ratio, assuming a market price of $10.00 per share.

(3)	Cash will be paid instead of issuing any fractional shares.

(4)	Includes 41,800,140 shares that may be issued as merger consideration to meet the minimum offering requirement, assuming 70% of the merger consideration is in stock, and which will be considered shares sold in the community offering for purposes of the offering range.

No fractional shares of Columbia Financial, Inc. common stock will be issued in the conversion and offering. For each fractional share that would otherwise be issued, we will pay cash in an amount equal to the product obtained by multiplying the fractional share interest to which the holder would otherwise be entitled by the $10.00 per share offering price.

Shares to Be Issued in the Offering, the Exchange and the Merger

The following table shows the total number of shares of Columbia Financial, Inc. common stock that will be outstanding after the completion of the offering, the exchange of shares of Columbia Financial for shares of Columbia Financial, Inc. and the completion of the merger with Northfield Bancorp, assuming that 70% of Northfield Bancorp’s outstanding shares of common stock are exchanged for shares of Columbia Financial, Inc. common stock and 30% of Northfield Bancorp’s outstanding shares of common stock are exchanged for cash in the merger. Information is presented at the adjusted minimum, minimum, midpoint and maximum of the offering range. Information presented at the adjusted minimum assumes 41,800,140 shares will be issued as merger consideration.


	Columbia Financial, Inc. Shares Issued in the Merger					Columbia Financial, Inc. Shares Sold in the Offering					Columbia Financial, Inc. Exchange Shares Issued to Minority Stockholders					Columbia Financial, Inc. Shares Outstanding
	Number		Percent of Shares Outstanding			Number		Percent of Shares Outstanding			Number		Percent of Shares Outstanding			Number		Percent of Shares Outstanding
Adjusted Minimum		41,800,140		21.46	%		100,574,860		51.64	%		52,382,845		26.90	%		194,757,845		100.00	%
Minimum		41,800,140		17.67	%		142,375,000		60.19	%		52,382,845		22.14	%		236,557,985		100.00	%
Midpoint		41,800,140		15.43	%		167,500,000		61.82	%		61,626,877		22.75	%		270,927,017		100.00	%
Maximum		42,973,477		14.02	%		192,625,000		62.85	%		70,870,908		23.12	%		306,469,385		100.00	%

The following table shows the total number of shares of Columbia Financial, Inc. common stock that will be outstanding after the completion of the offering, the exchange of shares of Columbia Financial for shares of Columbia Financial, Inc. and the completion of the merger with Northfield Bancorp, assuming that 100% of Northfield Bancorp’s outstanding shares of common stock are exchanged for shares of Columbia Financial, Inc. common stock in the merger. Information is presented at the adjusted minimum, minimum, midpoint and maximum of the offering range. Information presented at the adjusted minimum assumes 59,714,485 shares will be issued as merger consideration.


	Columbia Financial, Inc. Shares Issued in the Merger					Columbia Financial, Inc. Shares Sold in the Offering					Columbia Financial, Inc. Exchange Shares Issued to Minority Stockholders					Columbia Financial, Inc. Shares Outstanding
	Number		Percent of Shares Outstanding			Number		Percent of Shares Outstanding			Number		Percent of Shares Outstanding			Number		Percent of Shares Outstanding
Adjusted Minimum		59,714,485		30.66	%		82,660,515		42.44	%		52,382,845		26.90	%		194,757,845		100.00	%
Minimum		59,714,485		23.47	%		142,375,000		55.95	%		52,382,845		20.58	%		254,472,330		100.00	%
Midpoint		59,714,485		20.67	%		167,500,000		57.99	%		61,626,877		21.34	%		288,841,362		100.00	%
Maximum		61,390,681		18.90	%		192,625,000		59.29	%		70,870,908		21.81	%		324,886,589		100.00	%

How We Intend to Use the Proceeds of this Offering

The following table summarizes how we intend to use the proceeds of the offering, based on the sale of shares at the adjusted minimum, minimum midpoint and maximum of the offering range. The table below assumes the merger consideration for the acquisition of Northfield Bancorp includes 30% cash with the remainder of the consideration in common stock of Columbia Financial, Inc.


	Adjusted Minimum 142,375,000 Shares at $10.00 per share			Minimum 142,375,000 Shares at $10.00 per share			Midpoint 167,500,000 Shares at $10.00 Per share			Maximum 192,625,000 Shares at $10.00 per share
	(In thousands)
Gross offering proceeds	$	1,423,750		$	1,423,750		$	1,675,000		$	1,926,250
Less: offering expenses		(39,779	)		(36,311	)		(38,623	)		(43,070	)

Net offering proceeds		1,383,971			1,387,439			1,636,377			1,883,180
Less: merger shares used to complete the offering⁽¹⁾		(418,001	)		—			—			—

Net cash proceeds		965,970			1,387,439			1,636,377			1,883,180
Less:
Proceeds contributed to Columbia Bank		(482,985	)		(693,720	)		(818,189	)		(941,590	)
Proceeds used for loan to employee stock ownership plan		(42,713	)		(42,713	)		(50,250	)		(57,788	)
Cash merger consideration⁽²⁾		(179,143	)		(179,143	)		(179,143	)		(184,172	)

Proceeds remaining for Columbia Financial, Inc.	$	261,129		$	471,863		$	588,795		$	699,630

(1)

The number of shares of Columbia Financial, Inc. sold for cash at the adjusted minimum the offering will vary depending on market conditions and the amount of the merger consideration that is paid in shares of Columbia Financial, Inc. This column assumes that 70% of the merger consideration will be paid in shares of Columbia Financial, Inc., which would result in 100,574,860 shares that would need to be sold in the offering to satisfy the minimum offering requirement. If instead, 100% of the merger consideration is paid in shares of Columbia Financial, Inc., the number of shares required to be sold for cash to satisfy the minimum offering requirement would decrease at the adjusted minimum from 100,574,860 shares to 82,660,515 shares and the resulting net cash proceeds would be less than the amount shown in the table above. See “The Conversion and Offering — Shares Outstanding at the Completion of the Offering.”

(2)

We intend to contribute 50.0% of the net cash proceeds to Columbia Bank and, assuming 30% of the merger consideration is in cash, an additional $179.1 million will be used to fund the cash portion of the merger consideration at the adjusted minimum, minimum, and midpoint of the offering range and $184.2 million at the maximum of the offering range.

Initially, we intend to invest the proceeds of the offering in short-term investments and to fund the cash consideration in the merger. In the future, Columbia Financial, Inc. may use the funds it retains to invest in securities, pay cash dividends, repurchase shares of its common stock (subject to regulatory restrictions), or for general corporate purposes. Columbia Bank intends to use the portion of the proceeds that it receives to fund new loans, to invest in securities or for general corporate purposes. However, we have not allocated specific dollar amounts to any particular area of our loan portfolio. The amount of time that it will take to deploy the proceeds of the offering into loans will depend primarily on the level of loan demand. We may also use the proceeds of the offering to acquire other financial services companies or branches or open de novo branches as opportunities arise, primarily in or adjacent to our combined market areas following completion of the Northfield Bancorp merger, although we have no specific understandings or agreements to do so at this time.

Our Dividend Policy

Columbia Financial has not historically paid dividends to its minority stockholders because of Federal Reserve Board regulations and policies that substantially restrict non-grandfathered mutual holding companies, such as Columbia Bank MHC, from waiving dividends declared by its stock holding company.

yield based on a price of $10.00 per share. The initial dividend and continued payment of dividends will depend on a number of factors, including our financial condition and results of operations, tax considerations, capital requirements, alternative uses for capital, the number of shares issued in the offering, industry standards and economic conditions.

We cannot guarantee that we will pay dividends or that, if paid, we will not reduce or eliminate dividends in the future. See “Our Dividend Policy” for additional information.

Persons Who Can Order Stock in the Offering

We are offering shares of Columbia Financial, Inc. common stock for sale in a subscription offering in the following descending order of priority:

Persons with aggregate balances of $50 or more on deposit at Columbia Bank as of the close of business on December 31, 2024.

Our tax-qualified employee benefit plans.

Persons with aggregate balances of $50 or more on deposit at Columbia Bank (other than directors and executive officers of Columbia Bank) as of the close of business on March 31, 2026 who are not eligible in category 1 above.

Columbia Bank’s depositors as of the close of business on April 30, 2026 who are not eligible under categories 1 or 3 above and borrowers of Columbia Bank as of November 14, 1995 whose borrowings remained outstanding on April 30, 2026.

If we receive subscriptions for more shares than are to be sold in this offering, we may be unable to fill or may only partially fill your order. Shares will be allocated in order of the priorities described above and under procedures outlined in the plan of conversion. See “The Conversion and Offering — Subscription Offering and Subscription Rights” for a description of the allocation procedures.

Shares of common stock not purchased in the subscription offering may be offered for sale to the general public in a community offering, with a preference given first to natural persons (including trusts of natural persons) residing in Bergen, Burlington, Camden, Essex, Gloucester, Middlesex, Monmouth, Morris, Passaic, Somerset and Union counties in the State of New Jersey, then to existing stockholders of Columbia Financial (other than Columbia Bank MHC) and then to members of the general public. The community offering may begin concurrently with, or any time after, the subscription offering. We may offer for sale shares of common stock not purchased in the subscription offering or the community offering through a firm commitment offering. Our underwriters need to have sufficient orders to reach the adjusted minimum amount when combined with the number of shares issued in the merger in order to commence the firm commitment underwritten offering. We have the right to accept or reject, in our sole discretion, orders received in the community offering or in the firm commitment offering. Any determination to accept or reject stock orders in the community offering or the firm commitment offering will be based on the facts and circumstances available to management at the time of the determination.

Purchase Limitations

Pursuant to our plan of conversion, our board of directors has established limitations on the purchase of common stock in the offering. These limitations include the following:

•

The minimum purchase is 25 shares.

•

No individual (or individuals exercising subscription rights through a single qualifying account held jointly) may purchase more than $3,000,000 of common stock (which equals 300,000 shares) in the offering. In addition, if any of the following persons purchase shares of common stock, their purchases, in all categories of the offering combined, when aggregated with your purchases, cannot exceed $10,000,000 of common stock (which equals 1,000,000 shares):

•

any person who is related by blood or marriage to you and who either lives in your home or who is a director or officer of Columbia Bank, Columbia Financial, Inc., Columbia Financial or Columbia Bank MHC;

•

companies or other entities in which you are an officer or partner or have a 10% or greater beneficial ownership interest; and

•

trusts or other estates in which you have a substantial beneficial interest or as to which you serve as a trustee or in another fiduciary capacity.

Unless we determine otherwise, persons having the same address and persons exercising subscription rights through qualifying accounts registered to the same address will be subject to this overall purchase limitation. We have the right to determine, in our sole discretion, whether prospective purchasers are associates or acting in concert.

In addition, no individual, together with any associates, and no group of persons acting in concert may purchase shares of common stock so that, when combined with shares of Columbia Financial, Inc. common stock received in exchange for shares of Columbia Financial common stock, such person or persons would hold more than 9.9% of the number of shares of Columbia Financial, Inc. common stock outstanding upon completion of the conversion and offering. No person will be required to divest any shares of Columbia Financial, Inc. common stock or be limited in the number of shares of Columbia Financial, Inc. to be received in exchange for shares of Columbia Financial common stock as a result of this purchase limitation.

Subject to the Federal Reserve Board’s approval, we may increase or decrease the purchase limitations at any time. Our tax-qualified employee stock ownership plan is authorized to purchase up to 10% of the shares sold in the offering, without regard to these purchase limitations, although it currently expects to only subscribe for an amount equal to 3.0% of the shares sold in the offering.

Conditions to Completing the Conversion and Offering

We cannot complete the conversion and offering unless:

•

we sell at least the minimum number of shares offered (after giving effect to the adjusted minimum of the offering range, if applicable);

•

we receive the approval of the Federal Reserve Board to complete the conversion and offering and to acquire Columbia Bank in connection with the conversion and offering;

•

the plan of conversion is approved by at least a majority of votes eligible to be cast by members of Columbia Bank MHC;

•

the plan of conversion is approved by at least two-thirds of the outstanding shares of Columbia Financial, including shares held by Columbia Bank MHC; and

•

the plan of conversion is approved by at least a majority of the votes eligible to be cast by stockholders of Columbia Financial, excluding shares held by Columbia Bank MHC.

Columbia Bank MHC, which owns 73.1% of the outstanding shares of Columbia Financial, intends to vote these shares in favor of the plan of conversion. This would guarantee that the plan of conversion is approved by at least two-thirds of the outstanding shares of Columbia Financial, including shares held by Columbia Bank MHC. In addition, as of April 30, 2026, directors and executive officers of Columbia Financial and their associates beneficially owned 3,904,821 shares of Columbia Financial, or 3.75% of the outstanding shares of Columbia Financial, and they intend to vote those shares in favor of the plan of conversion.

In addition, each of the directors of Columbia Financial has entered into a support agreement pursuant to which, among other things, each such director has agreed, subject to the terms of the support agreement, to vote the shares of Columbia Financial common stock over which he or she has the sole power to vote or direct the voting of in favor of the approval of the plan of conversion. As of April 30, 2026, the members of the board of directors of Columbia Financial owned and held the sole dispositive and voting power over 1,195,072 shares of Columbia Financial common stock.

In the event that the merger with Northfield Bancorp is terminated, Columbia Financial may determine to terminate the conversion or delay the conversion. If it determines to delay the conversion, the timing and manner of the conversion would be subject to significant modification and subscribers would have the right to modify or rescind their purchase orders.

Steps We May Take if We Do Not Receive Orders for the Minimum Number of Shares

If we do not receive orders for at least 142,375,000 shares of common stock, we may issue up to 41,800,140 unsubscribed shares to the stockholders of Northfield Bancorp in the merger to achieve the minimum of the offering

range. If Columbia Financial, Inc. applies 41,800,140 unsubscribed shares to the merger, which assumes 70% of the merger consideration is paid in shares, then the minimum number of shares that Columbia Financial, Inc. must sell for cash in the offering is 100,574,860 shares. In addition, we may take several steps in order to sell the minimum number of shares of common stock in the offering range. Specifically, we may:

(i)

increase the purchase and ownership limitations; and/or

(ii)

seek regulatory approval to extend the offering beyond July 31, 2026, so long as we resolicit subscribers who previously submitted subscriptions in the offering.

If we extend the offering past July 31, 2026, all subscribers will be notified and given an opportunity to confirm, change or cancel their orders. If you do not respond to that notice, we will cancel your stock order and promptly return your funds with interest at 0.40% per annum for funds received in the subscription and community offering or cancel your deposit account withdrawal authorization. If one or more of the purchase limitations are increased, only those subscribers in the subscription offering who ordered the maximum amount and who indicated on their stock order form an interest in being resolicited will be given the opportunity to increase their subscriptions up to the then-applicable limit.

How to Purchase Common Stock

In the subscription offering and the community offering, you may pay for your shares by:

personal check, bank check or money order made payable directly to “Columbia Financial, Inc.” (Columbia Bank lines of credit checks and third-party checks of any type will not be accepted);

authorizing us to withdraw available funds (without any early withdrawal penalty) from your Columbia Bank deposit account(s), other than checking accounts, individual retirement accounts (“IRAs”) or health savings accounts (“HSAs”). To use funds from accounts with check writing privileges, please submit a check. To use IRA funds, please see “— Using IRA Funds to Purchase Shares in the Offering”; or

cash. Cash will only be accepted at the Corporate Headquarters and the East Brunswick office of Columbia Bank and will be converted to a bank check. Please do not submit cash by mail.

Columbia Bank is not permitted to knowingly lend funds (including funds drawn on a Columbia Bank line of credit) to anyone to purchase shares of common stock in the offering. Also, payment may not be made by wire transfer.

You may not designate on your stock order form a direct withdrawal from a retirement account at Columbia Bank. See “— Using IRA Funds to Purchase Shares in the Offering.” Additionally, you may not designate withdrawal from a Columbia Bank account with check-writing privileges; rather, submit a check. If you request a withdrawal from an account with check-writing privileges, we reserve the right to interpret that as your authorization to treat those funds as if we had received a check for the designated amount and will immediately withdraw the amount from the specified account(s).

Personal checks and money orders will be immediately cashed, so the funds must be available within the account when your original stock order form and check are received by us. Subscription funds submitted by check or money order will be held in a segregated account at Columbia Bank. We will pay interest calculated at Columbia Bank’s statement savings rate from the date those funds are received until completion or termination of the offering. Withdrawals from certificate of deposit accounts at Columbia Bank to purchase common stock in the offering may be made without incurring an early withdrawal penalty. All funds authorized for withdrawal from deposit accounts with Columbia Bank must be available within the deposit accounts at the time the stock order form is received. A hold will be placed on the amount of funds designated on your stock order form. Those funds will be unavailable to you during the offering; however, the funds will not be withdrawn from the accounts until the offering is completed and will continue to earn interest at the applicable contractual deposit account rate until the completion of the offering. If, upon a withdrawal from a certificate of deposit account, the balance falls below the minimum balance requirement, the remaining funds will earn interest at the current statement savings rate.

You may deliver your stock order form in one of three ways: (1) by paying for overnight delivery to the address listed on the stock order form; (2) by hand-delivery to our Corporate Headquarters located at 19-01 Route 208 North, Fair Lawn, New Jersey or to our East Brunswick office located at 389 Route 18 South, East Brunswick, New Jersey (hand-delivered stock order forms will only be accepted at these locations); or (3) by mail, using the stock order reply envelope provided. Stock order forms may not be hand-delivered to Columbia Bank offices not listed above and should not be mailed to Columbia Bank. Once submitted, your order is irrevocable. We are not required to accept copies or facsimiles of order forms.

Using IRA Funds to Purchase Shares in the Offering

You may be able to subscribe for shares of common stock using funds in your individual retirement account(s), or IRA. If you wish to use some or all of the funds in your Columbia Bank IRA or other retirement account, the applicable funds must first be transferred to a self-directed retirement account maintained by an unaffiliated institutional trustee or custodian, such as a brokerage firm. An annual fee may be payable to the new trustee. If you do not have such an account, you will need to establish one and transfer your funds before placing your stock order. There will be no early withdrawal penalty for this transfer by Columbia Bank. Individuals interested in using funds in an individual retirement account or any other retirement account, whether held at Columbia Bank or elsewhere, to purchase shares of common stock should contact our Stock Information Center for guidance as soon as possible, preferably at least two weeks before the June 16, 2026 offering deadline. Processing such transactions takes additional time, and whether such funds can be used may depend on limitations imposed by the institutions where such funds are currently held. We cannot guarantee that you will be able to use such funds.

Purchases by Directors and Executive Officers

We expect that our directors and executive officers, together with their associates, will subscribe for approximately 422,500 shares, which is 0.3% of the shares offered at the midpoint of the offering. Our directors and executive officers will pay the same $10.00 per share price as everyone else who purchases shares in the offering. Like all of our depositors, our directors and executive officers have subscription rights based on their deposits and, in the event of an oversubscription, their orders will be subject to the allocation provisions set forth in our plan of conversion. Purchases by our directors and executive officers will count towards the minimum number of shares we must sell to close the offering. Following the conversion and offering, and including shares received in exchange for shares of Columbia Financial, our directors and executive officers, together with their associates, are expected to own 4,799,406 shares of Columbia Financial, Inc. common stock, which would equal 2.1% of our outstanding shares if 167,500,000 shares are sold at the midpoint of the offering range.

Deadline for Ordering Stock in the Subscription and Community Offerings

The subscription offering will end at 2:00 p.m. Eastern time, on June 16, 2026. If you wish to purchase shares, a properly completed and signed original stock order form, together with full payment for the shares of common stock, must be received (not postmarked) no later than this time. We expect that the community offering, if held, will terminate at the same time, although it may continue until July 31, 2026 or longer if the Federal Reserve Board approves a later date. No single extension may be for more than 90 days. We are not required to provide notice to you of an extension unless we extend the offering beyond July 31, 2026 in which case all subscribers in the subscription and community offerings will be notified and given the opportunity to confirm, change or cancel their orders. If you do not respond to this notice, we will promptly return your funds with interest calculated at Columbia Bank’s statement savings rate or cancel your deposit account withdrawal authorization. If we intend to sell fewer than 142,375,000 shares or more than 192,625,000 shares, we will promptly return all funds and set a new offering range. All subscribers will be notified and given the opportunity to place a new order.

Benefits of the Conversion to Management

We will recognize additional compensation expense related to the expanded employee stock ownership plan and the intended new equity incentive plan. The actual expense will depend on the market value of our common stock and will increase if the value of our common stock increases. As reflected under “Pro Forma Data,” based upon assumptions set forth therein, the annual expense related to the employee stock ownership plan and the intended new equity incentive plan would have been $11.7 million for the year ended December 31, 2025 on an after-tax basis, assuming shares had been sold at the maximum of the offering range. If awards under the intended new equity incentive plan are funded from authorized but unissued stock, your ownership interest would be diluted by up to approximately 5.16%. See “Pro Forma Data” for an illustration of the effects of each of these plans.

Employee Stock Ownership Plan. In connection with our reorganization to the mutual holding company structure in 2018, Columbia Bank’s employee stock ownership plan purchased 4,542,855 shares of Columbia Financial common stock using funds borrowed from Columbia Financial. As of December 31, 2025, the balance of the loan from Columbia Financial to the employee stock ownership plan was $32.7 million.

Our existing employee stock ownership plan intends to purchase an amount of shares equal to 3.0% of the shares sold in the offering. The plan will use the proceeds from a 25-year loan from Columbia Financial, Inc. to purchase

these shares. We may purchase shares of common stock in the open market following the offering to fund all or a portion of the intended purchases, subject to Federal Reserve Board approval. As the loan is repaid and shares are released from collateral, the shares will be allocated to the accounts of employee participants based on an individual’s compensation as a percentage of total plan compensation. Non-employee directors are not eligible to participate in the plan. We will incur additional compensation expense as a result of this plan. See “Pro Forma Data” for an illustration of the effects of this plan.

New Equity Incentive Plan. We intend to implement a new equity incentive plan no earlier than six months after completion of the conversion and offering. We will submit this plan to our stockholders for their approval. Under this plan, we may grant stock options in an amount up to 6.20% of the number of shares sold in the offering and restricted stock awards or restricted stock units in an amount up to 2.45% of the shares sold in the offering. Stock options will be granted at an exercise price equal to 100% of the fair market value of our common stock on the option grant date. Shares of restricted stock and/or restricted stock units will be awarded at no cost to the recipient. We will incur additional compensation expense as a result of this plan. See “Pro Forma Data” for an illustration of the effects of this plan. The new equity incentive plan may award a greater number of options and restricted stock if the plan is adopted after one year from the date of the completion of the conversion. We have not yet determined the number of shares that would be reserved for issuance under this plan. The new equity incentive plan will comply with all applicable Federal Reserve Board regulations.

The following table summarizes, at the maximum of the offering range, the total number and value of the shares of common stock that the employee stock ownership plan expects to acquire and the total value of all restricted stock awards/restricted stock units and stock options that are expected to be available under the new equity incentive plan (assuming the equity incentive plan is implemented within one year following the completion of the conversion).


	Number of Shares to be Granted or Purchased
	At the Maximum of the Offering Range⁽¹⁾		As a Percentage of Common Stock to be Issued in the Offering			Dilution Resulting from the Issuance of Shares for Stock Benefit Plans			Total Estimated Value at Maximum of Offering Range (in thousands)
Employee stock ownership plan⁽²⁾		5,778,750		3.00	%		NM		$	57,788
Restricted stock⁽³⁾		4,719,313		2.45			1.52	%	$	47,193
Stock options⁽⁴⁾		11,942,750		6.20			3.75	%	$	41,441

Total		22,440,813		11.65	%		5.16	%	$	146,422

(1)	At the maximum of the offering range, we will sell 192,625,000 shares.

(2)	No dilution is reflected for the employee stock ownership plan because these shares are assumed to be purchased in the offering at the offering price of $10.00 per share.

(3)	The actual value of restricted stock awards will be determined based on their fair market value as of the date grants are made. For purposes of this table, fair value for stock awards is assumed to be the same as the offering price of $10.00.

(4)	Assumes the value of a stock option is $3.20, which was determined using the Black-Scholes option pricing formula. See “Pro Forma Data.”

We plan to fund our equity incentive plan through open market purchases, as opposed to new issuances of authorized common stock. Federal Reserve Board regulations do not permit us to repurchase our shares during the first year following the completion of this offering except to fund the grants of restricted stock under the stock-based incentive plan or, with prior regulatory approval, under extraordinary circumstances.

The following table presents information regarding our existing employee stock ownership plan and additional shares to be purchased by our employee stock ownership plan. The table below assumes that 306,469,385 shares are outstanding after the offering, and the merger, which includes the sale of 192,625,000 shares in the offering at the maximum of the offering range, the issuance of 70,870,908 shares in exchange for shares of Columbia Financial using an exchange ratio of 2.5340 and the issuance of 42,973,477 shares to Northfield Bancorp stockholders in the merger. It is also assumed that the value of the stock is $10.00 per share.


	Eligible Participants		Number of Shares at Maximum of Offering Range		Estimated Value of Shares		Percentage of Shares Outstanding after the Conversion and Offering
		Employees
Employee Stock Ownership Plan:
Shares purchased in 2018 offering⁽¹⁾				11,511,595	$	115,115,950		3.76	%
Shares to be purchased in this offering				5,778,750		57,787,500		1.89

Total				17,290,345	$	172,903,450		5.64	%

(1)

Represents 4,542,855 shares purchased in Columbia Financial’s 2018 minority stock offering, as adjusted for the 2.5340 exchange ratio at the maximum of the offering range. As of December 31, 2025, approximately 1,511,000 of these shares had been allocated to the accounts of participants and approximately 2,793,000 shares remain unallocated.

Market for Columbia Financial, Inc.’s Common Stock

Columbia Financial’s common stock is currently listed on the Nasdaq Global Select Market (“Nasdaq”) under the trading symbol “CLBK.” We expect the shares of Columbia Financial, Inc. common stock will continue to be listed on the Nasdaq under the symbol “CLBK” upon the completion of the conversion. Once shares of the common stock begin trading, you may contact a stockbroker to buy or sell shares. Persons purchasing the common stock in the offering may not be able to sell their shares at or above the $10.00 offering price. Brokerage firms typically charge commissions related to the purchase or sale of securities.

Subscription Rights are Not Transferable

Applicable regulations prohibit you from transferring your subscription rights. If you order shares of common stock in the subscription offering, you will be required to certify that you are purchasing the common stock for yourself and that you have no agreement or understanding to sell or transfer your subscription rights or the shares that you are purchasing. We intend to take legal action, including reporting persons to federal or state agencies, against anyone who we believe has sold or transferred his or her subscription rights. We will not accept your order if we have reason to believe you have sold or transferred your subscription rights. On the stock order form, you cannot add the names of others for joint stock registration who do not have subscription rights or who qualify only in a lower subscription offering priority than you do. Doing so may jeopardize your subscription rights. You may only add those who were eligible to purchase shares of common stock in the subscription offering on your date of eligibility. In addition, the stock order form requires that you list all accounts, giving all names on each account and the account number at the applicable eligibility date. Failure to provide this information, or providing incomplete or incorrect information, may result in a loss of part or all of your share allocation if there is an oversubscription.

Delivery of Prospectus

To ensure that each person receives a prospectus at least 48 hours before the deadline for orders for common stock, we may not mail prospectuses any later than five days before such date or hand-deliver prospectuses later than two days before that date. Stock order forms may only be delivered if accompanied or preceded by a prospectus. We are not obligated to deliver a prospectus or stock order form by means other than U.S. mail.

We will make reasonable attempts to provide a prospectus and offering materials to holders of subscription rights. The subscription offering and all subscription rights will expire at 2:00 p.m., Eastern time, on June 16, 2026, whether or not we have been able to locate each person entitled to subscription rights.

Once Submitted, Your Stock Purchase Order May Not Be Revoked Except Under Certain Circumstances

Funds that you submit to purchase shares of our common stock in the offering will be held in a segregated account at Columbia Bank, or at our discretion, at another insured depository institution, until the termination or completion of the offering, including any extension of the expiration date. Because completion of the conversion is subject to the receipt of all required regulatory approvals, including an update of the independent appraisal, among other factors, there may be one or more delays in the completion of the conversion. Any orders that you submit to purchase shares of our common stock in the offering are irrevocable, and you will not have access to subscription funds unless the offering is terminated, significantly modified, or extended beyond July 31, 2026 or the number of shares to be sold in the offering is increased to more than 192,625,000 shares or decreased to fewer than 142,375,000 shares or in the event the merger is terminated.

Tax Consequences

As a general matter, (1) the conversion will not be a taxable transaction for purposes of federal or state income taxes to us or to existing stockholders of Columbia Financial who receive Columbia Financial, Inc. common stock in exchange for their Columbia Financial common stock and (2) the conversion will not be a taxable transaction for purposes of federal or state income taxes to us or persons who receive or exercise subscription rights. Existing stockholders of Columbia Financial who receive cash in lieu of fractional share interests in shares of Columbia Financial, Inc. will recognize gain or loss equal to the difference between the cash received and the tax basis of the fractional share. Kilpatrick Townsend & Stockton LLP and Crowe LLP have issued us opinions to this effect, which are summarized under “The Conversion and Offering — Material U.S. Federal Income Tax Consequences of the Conversion and Offering.”

Book Entry Delivery

All shares of common stock sold will be issued in book entry form. Stock certificates will not be issued. A statement reflecting ownership of shares of common stock issued in the subscription and community offerings or in the firm commitment offering will be mailed by our transfer agent to the persons entitled thereto at the registration address noted by them on their stock order forms as soon as practicable following consummation of the conversion and offering. We expect trading in the stock to begin on the day of the completion of the conversion and offering or the next business day. The conversion and offering are expected to be completed as soon as practicable following satisfaction of the conditions described above in “— Conditions to Completing the Conversion and Offering.” It is possible that until a statement reflecting ownership of shares of common stock is available and delivered to purchasers, purchasers might not be able to sell the shares of common stock that they purchased, even though the common stock will have begun trading. Your ability to sell your shares of common stock before receiving your statement will depend on arrangements you may make with a brokerage firm.

Stock Information Center

Our banking office personnel may not, by law, assist with investment-related questions about the offering. If you have any questions regarding the offering, please call our Stock Information Center. The telephone number is [●]. The Stock Information Center is open Monday through Friday between 10:00 a.m. and 4:00 p.m., Eastern time. The Stock Information Center will be closed on weekends and bank holidays.

RISK FACTORS

You should consider carefully the following risk factors in evaluating an investment in the shares of our common stock. An investor should carefully consider the following risk factors before deciding to make an investment decision regarding Columbia Financial, Inc.’s common stock. Consideration should also be given to the other information in this prospectus.

Summary of Risk Factors

Merger Risks:

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If the conversion is not consummated, our merger with Northfield Bancorp will not take place.

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If the merger with Northfield Bancorp does not occur, the conversion and offering would be delayed or terminated.

•

The dilution caused by the issuance of shares of Columbia Financial, Inc.’s common stock in connection with the merger may adversely affect the market price of Columbia Financial, Inc.’s common stock.

•

Combining Columbia Financial, Inc. and Northfield Bancorp may be more difficult, costly or time consuming than expected, and Columbia Financial, Inc. may not realize the anticipated benefits of the acquisition.

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Columbia Financial has incurred, and Columbia Financial, Inc. following the closing of the merger, will incur significant transaction and transaction-related costs in connection with the transactions contemplated by the merger agreement.

•

Regulatory approvals for the merger may not be received, may take longer than expected or may impose conditions that are not currently anticipated or that could have an adverse effect on Columbia Financial, Inc. following the closing.

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The merger agreement may be terminated in accordance with its terms and the merger may not be completed, which could cause the results of Columbia Financial to be adversely affected, the stock prices of Columbia Financial to decline or have a material and adverse effect on the stock price of Columbia Financial and its results of operations.

•

The market price for Columbia Financial, Inc. common stock following the closing of the merger may be affected by factors different from those that historically have affected or currently affect Columbia Financial common stock.

•

The future results of Columbia Financial, Inc. following the closing of the merger may suffer if Columbia Financial, Inc. does not effectively manage its expanded operations.

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Columbia Financial will be subject to business uncertainties and contractual restrictions while the merger is pending.

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Holders of Columbia Financial common stock will have a reduced ownership and voting interest in the surviving corporation after the merger and will exercise less influence over management.

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The merger will not be completed unless important conditions are satisfied or waived, including approval of the merger by Northfield Bancorp stockholders, approval of the merger and the conversion by Columbia Financial stockholders, and approval of the conversion by the members of Columbia Bank MHC.

•

Litigation against Columbia Financial or Northfield Bancorp, or the members of Columbia Financial’s or Northfield Bancorp’s board of directors, could prevent or delay the completion of the merger.

•

The unaudited pro forma condensed combined financial information included in this prospectus is preliminary and the actual financial condition and results of operations of the surviving corporation after the merger may differ materially.

Lending Activities Risks:

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Our multifamily and commercial real estate lending practices expose us to increased lending risks and related loan losses.

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Imposition of limits by the bank regulators on commercial and multifamily real estate lending activities could curtail our growth and adversely affect our earnings.

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Our origination of construction loans exposes us to increased lending risks.

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Our concentration of residential mortgage loans exposes us to increased lending risks.

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Our commercial business lending activities expose us to additional lending risks.

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If our allowance for credit losses is not sufficient to cover actual loan losses, our results of operations would be negatively affected.

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The geographic concentration of our loan portfolio and lending activities makes us vulnerable to a downturn in the New Jersey, metropolitan New York and Philadelphia economies.

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Economic conditions could result in increases in our level of non-performing loans and/or reduce demand for our products and services, which could have an adverse effect on our results of operations.

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Northfield Bancorp’s New York multifamily loan portfolio may continue to be adversely affected by changes in legislation or regulation.

Growth Strategies Risks:

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Our business strategy includes growth, and our financial condition and results of operations could be negatively affected if we fail to grow or fail to manage our growth effectively. Growing our operations could also cause our expenses to increase faster than our revenues.

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We are subject to certain risks in connection with our strategy of growing through mergers and acquisitions.

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We may be required to write down goodwill and other acquisition-related identifiable intangible assets.

General Business and Industry Risks:

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Ineffective liquidity management could adversely affect our financial results and condition.

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Changes in interest rates or the shape of the yield curve may hurt our profits and asset values and our strategies for managing interest rate risk may not be effective.

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The fair value of our investments has declined materially in the past and could decline further due to a variety of factors.

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Financial challenges at other banking institutions could lead to depositor concerns that spread within the banking industry causing disruptive and destabilizing deposit outflows.

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Municipal deposits are an important source of funds for us and a reduced level of such deposits may hurt our profits.

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We are dependent on our information technology and telecommunications systems and third-party service providers; systems failures, interruptions and cybersecurity breaches could have a material adverse effect on us.

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Security breaches and cybersecurity threats could compromise our information and expose us to liability, which would cause our business and reputation to suffer.

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We must keep pace with technological change to remain competitive.

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Our business may be materially affected by the emergence of disruptive new technologies or approaches enabled by the rapid pace of innovation unfolding in the artificial intelligence space.

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Because the nature of the financial services business involves a high volume of transactions, we face significant operational risks.

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The building of market share through our branch office strategy, and our ability to achieve profitability on new branch offices, may increase our expenses and negatively affect our earnings.

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Strong competition within our market area could hurt our profits and slow growth.

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Acts of terrorism and other external events could impact our ability to conduct business.

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Climate change, severe weather, global pandemics, natural disasters, and other external events could significantly impact our business.

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Rapidly evolving economic, social and political conditions or civil unrest in the United States may affect the markets in which we operate, our customers, our ability to provide customer service, and could have a material adverse impact on our business, results of operations, or financial condition.

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Regulation of the financial services industry is intense, and we may be adversely affected by changes in laws and regulations.

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We may be unable to disclose some regulatory restrictions or limitations on our operations imposed by our regulators, even if material to our business.

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As a larger financial institution, we are subject to additional regulation and increased supervision.

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We face significant legal risks, both from regulatory investigations and proceedings, and from potential private actions brought against us.

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Our ability to manage reputational risk is critical to attracting and maintaining customers, investors and employees and to the success of our business, and the failure to do so may materially adversely affect our performance.

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We are subject to environmental, social and governance risks that could adversely affect our reputation and the trading price of our common stock.

Offering Risks:

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The future price of the shares of common stock may be less than the $10.00 purchase price per share in the offering.

•

Various factors may have an adverse effect on our financial performance.

•

Our return on equity may be low following the offering, which could negatively affect the trading price of our shares of common stock.

•

Our stock-based benefit plans will increase our expenses and reduce our income.

•

The implementation of stock-based benefit plans may dilute your ownership interest.

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We have not determined when we will adopt one or more new stock-based benefit plans. Stock-based benefit plans adopted more than 12 months following the completion of the conversion may exceed regulatory restrictions on the size of stock-based benefit plans adopted within 12 months, which would further increase our costs.

•

Various factors may make takeover attempts more difficult to achieve.

•

Our bylaws provide that, subject to limited exceptions, state and federal courts in the State of Maryland are the sole and exclusive forum for certain stockholder litigation matters, which could limit our stockholders’ ability to obtain a favorable judicial forum for disputes with us or our directors, officers, and other employees.

•

The market price of our stock value may be negatively affected by applicable regulations that restrict stock repurchases by Columbia Financial, Inc.

•

You may not revoke your decision to purchase shares of Columbia Financial, Inc. common stock in the subscription or community offerings after you send us your order.

•

The distribution of subscription rights could have adverse income tax consequences.

Risks Related to the Merger

If the conversion is not consummated, our merger with Northfield Bancorp will not take place.

Our acquisition of Northfield Bancorp depends upon our successful conversion from the mutual holding company form of organization to stock form of organization. The conversion requires stockholder and member approvals as well as the approval of the federal banking regulatory authorities, one or more of which we may not obtain in a timely manner, or at all. The conversion also depends upon the successful implementation of our plan of conversion as described in the section entitled “The Conversion.” If we are unable to consummate the conversion, our acquisition of Northfield Bancorp will not take place. Our failure to acquire Northfield Bancorp could effect our ability to generate profits and grow our franchise, which could have a material adverse affect on our pro forma results of operations and financial condition if we determined to terminate the conversion.

If the merger with Northfield Bancorp does not occur, the conversion and offering would be delayed or terminated.

We anticipate simultaneously completing the conversion, the offering and the Northfield Bancorp acquisition in the third quarter of 2026. At this time, we are not aware of any circumstances that are likely to cause the acquisition not to occur. However, certain conditions to the merger have not yet been satisfied, including regulatory approvals and stockholder approvals. Also, a material adverse change in Northfield Bancorp may preclude consummation of the acquisition. If the Northfield Bancorp acquisition were not to occur, we may terminate the conversion or delay the conversion. If the merger is terminated and we determine to terminate the conversion and offering, we will promptly return your funds with interest calculated at Columbia Bank’s statement savings rate and all deposit account withdrawal authorizations would be cancelled. In the event we determined to proceed with the conversion and offering without the acquisition, the timing and manner of the conversion would be subject to significant modifications including an updated appraisal, changes in the use of proceeds from the offering and potential changes in our ongoing business plan given we would be undertaking the conversion on a stand alone basis. The offering documents would be revised and subscribers in the offering would be re-solicited with an amended proxy statement and prospectus. As a result, if we were to proceed with the conversion without the merger the conversion and the offering would be delayed.

The dilution caused by the issuance of the new shares of Columbia Financial, Inc. common stock to Northfield Bancorp stockholders in connection with the payment of the merger consideration may result in fluctuations in the market price of Columbia Financial, Inc. common stock, including a stock price decrease, following the closing of the conversion.

A successful integration of Northfield Bancorp’s business with Columbia Financial, Inc.’s business will depend substantially on the ability to consolidate operations, corporate cultures, systems and procedures and to eliminate redundancies and costs. Columbia Financial, Inc. may not be able to combine each company’s business without encountering difficulties that could adversely affect the ability to maintain relationships with existing clients, customers, depositors and employees, such as:

•

the loss of key employees;

•

the disruption of operations and business;

•

inability to maintain and increase competitive presence;

•

loan and deposit attrition, customer loss and revenue loss;

•

possible inconsistencies in standards, control procedures and policies;

•

additional costs or unexpected problems with operations, personnel, technology and credit; and/or

•

problems with the assimilation of new operations, systems, sites or personnel, which could divert resources from regular banking operations.

Any disruption to the businesses could cause customers to remove their accounts and move their business to a competing financial institution. Integration efforts between the two companies may also divert management attention and resources. Additionally, general market and economic conditions or governmental actions affecting the financial industry generally may inhibit the successful integration of Columbia Financial, Inc. and Northfield Bancorp.

Further, Columbia Financial, Inc. and Northfield Bancorp entered into the merger agreement with the expectation that the acquisition of Northfield Bancorp by Columbia Financial, Inc. will result in various benefits including, among other things, benefits relating to enhanced revenues, a strengthened market position for the surviving corporation, cross selling opportunities, technological efficiencies, cost savings and operating efficiencies. Achieving the anticipated benefits of the transactions contemplated by the merger agreement is subject to a number of uncertainties, including whether the integration is completed in an efficient, effective and timely manner, and general competitive factors in the marketplace. Failure to achieve these anticipated benefits on the anticipated timeframe, or at all, could result in a reduction in the price of Columbia Financial, Inc.’s common stock as well as increased costs, decreases in the amount of expected revenues and diversion of management’s time and energy and could materially and adversely affect Columbia Financial, Inc.’s business, financial condition and operating results. Additionally, upon consummation of the transactions contemplated by the merger agreement, Columbia Financial, Inc. will make fair value estimates of certain assets and liabilities in recording the acquisition. Actual values of these assets and liabilities could differ from such estimates, which could result in Columbia Financial, Inc. not achieving the anticipated benefits of the acquisition. Finally, any cost savings that are realized may be offset by losses in revenues or other charges to earnings.

Columbia Financial and Northfield Bancorp have incurred and Columbia Financial, Columbia Financial, Inc. and Northfield Bancorp expect to incur significant non-recurring costs associated with combining the operations of Columbia Financial, Inc. and Northfield Bancorp. These costs include legal, financial advisory, accounting, consulting and other advisory fees, severance/employment-related costs, public company filing fees and other regulatory fees, printing costs and other related costs. We will also incur significant costs relating to contract termination fees for vendor contracts currently utilized by Northfield Bancorp in its operations. Columbia Financial and Northfield Bancorp have begun collecting information in order to formulate detailed integration plans to deliver anticipated cost savings; however, many of the costs that will be incurred are, by their nature, difficult to estimate accurately. Additional unanticipated costs may be incurred in the integration of the businesses of Columbia Financial and Northfield Bancorp, and there are many factors beyond Columbia Financial’s, Columbia Financial, Inc.’s and Northfield Bancorp’s control that could affect the total amount or timing of integration costs. Although Columbia Financial and Northfield Bancorp expect that the elimination of duplicative costs, as well as the realization of other efficiencies related to the integration of the businesses, may offset incremental transaction and transaction-related costs over time, this net benefit may not be achieved in the near term, or at all.

Whether or not the merger is consummated, Columbia Financial, Columbia Financial, Inc. and Northfield Bancorp will incur substantial expenses in pursuing the merger and may adversely impact Columbia Financial’s, Columbia Financial, Inc.’s and Northfield Bancorp’s earnings. The completion of the merger is conditioned upon customary closing conditions, including the receipt of required governmental authorizations, consents, orders and approvals, including approval by certain federal banking regulators and required approvals from the stockholders of Columbia Financial and Northfield Bancorp. Columbia Financial and Northfield Bancorp intend to pursue all required approvals in accordance with the merger agreement. However, these approvals could be delayed or not obtained at all, and there can be no assurance that such approvals will be obtained without additional cost, on the anticipated timeframe, or at all.

Before the merger and transactions contemplated by the merger agreement may be completed, various approvals, consents and non-objections must be obtained from regulatory authorities. In determining whether to grant these approvals,

regulatory authorities consider a variety of factors, including the regulatory standing of each party. These approvals could be delayed or not obtained at all, including due to any or all of the following: an adverse development in any party’s regulatory standing or any other factors considered by regulators in granting such approvals, governmental, political or community group inquiries, investigations or opposition; changes in legislation or the political environment, including as a result of changes of the U.S. executive administration, or Congressional leadership and regulatory agency leadership.

Even if the approvals are granted, they may impose terms and conditions, limitations, obligations or costs, or place restrictions on the conduct of the surviving corporation’s business or require changes to the terms of the transactions contemplated by the merger agreement. There can be no assurance that regulators will not impose any such conditions, limitations, obligations or restrictions or that such conditions, limitations, obligations or restrictions will not have the effect of delaying the completion of any of the transactions contemplated by the merger agreement, imposing additional material costs on or materially limiting the revenues of Columbia Financial, Inc. following the closing of the merger or will otherwise reduce the anticipated benefits of the merger. In addition, there can be no assurance that any such conditions, limitations, obligations or restrictions will not result in the delay or abandonment of the merger and the transactions contemplated by the merger agreement. Additionally, the completion of the merger is conditioned on the absence of certain orders, injunctions or decrees by any governmental entity of competent jurisdiction that would prohibit or make illegal the completion of the merger and the transactions contemplated by the merger agreement.

Despite the parties’ expected commitment to use their reasonable best efforts to respond to any request for information and resolve any objection that may be asserted by any governmental entity with respect to the merger agreement, neither party is required under the terms of the merger agreement to take any action, commit to take any action, or agree to any condition or restriction in connection with obtaining these approvals, that would reasonably be expected to have a material adverse effect on Columbia Financial, Inc. and its subsidiaries, taken as a whole, after giving effect to the merger (measured on a scale relative only to the size of Northfield Bancorp and its subsidiaries, taken as a whole, without Columbia Financial and its subsidiaries).

If the merger is not completed for any reason, including as a result of Columbia Financial’s failure to complete the conversion, the failure of Columbia Financial’s stockholders to approve the merger or the conversion, or the failure of Northfield Bancorp’s stockholders to approve the merger, there may be various adverse consequences and Columbia Financial may experience negative reactions from the financial markets and from its respective customers and employees. Certain costs related to the transactions contemplated by the merger agreement, such as legal, accounting and certain financial advisory fees, must be paid even if the merger is not completed. Moreover, Columbia Financial may be required to pay a termination fee to Northfield Bancorp upon a termination of the merger agreement in certain circumstances. In addition, if the merger is not completed, whether because of the failure to receive required regulatory approvals in a timely fashion or because one of the parties has breached its obligations in a way that permits termination of the merger agreement, or for any other reason, Columbia Financial’s stock price may decline to the extent that the current market price reflects a market assumption that the merger will be completed.

Subject to the terms and conditions of the merger agreement, at the effective time of the merger, holders of Northfield Bancorp common stock will receive shares of Columbia Financial, Inc. common stock as merger consideration. Columbia Financial, Inc.’s business and financial position will differ from the business and financial position of Columbia Financial and Northfield Bancorp before the completion of the merger and, accordingly, the results of operations of Columbia Financial, Inc. will be affected by some factors that are different from those currently affecting Columbia Financial’s results of operations and those currently affecting the results of operations of Northfield Bancorp. Accordingly, the market price and performance of the surviving corporation’s common stock is likely to be different from the performance of Columbia Financial common stock in the absence of the merger. In addition, general fluctuations in stock markets could have a material adverse effect on the market for, or liquidity of, Columbia Financial, Inc.’s common stock, regardless of actual operating performance.

The future results of Columbia Financial, Inc. following the closing of the merger may suffer if Columbia Financial, Inc. does not effectively manage its expanded operations.

Following the completion of the merger, the size of the business of Columbia Financial, Inc. will increase significantly beyond the current size of Columbia Financial’s business. Columbia Financial, Inc.’s future success will depend, in part,

upon its ability to manage this expanded business, including its expansion into the Staten Island and Brooklyn markets currently served by Northfield Bancorp, which may pose challenges for management, including challenges related to the management and monitoring of new operations and markets, as well as associated increased costs and complexity. Columbia Financial, Inc. may also face increased scrutiny from governmental authorities as a result of the significant increase in the size of its business.

Columbia Financial will be subject to business uncertainties and contractual restrictions while the merger is pending.

Uncertainty about the effect of the merger on employees and customers may have an adverse effect on Columbia Financial and Northfield Bancorp. These uncertainties may impair Columbia Financial’s ability to attract, retain and motivate key personnel until the merger is completed, and could cause customers and others that deal with Columbia Financial to seek to change existing business relationships with Columbia Financial.

Holders of Columbia Financial common stock will have a reduced ownership and voting interest in the surviving corporation after the merger and will exercise less influence over management.

Holders of Columbia Financial common stock currently have the right to vote in the election of the board of directors and on other matters affecting Columbia Financial. Based on the number of shares of Northfield Bancorp common stock outstanding and reserved for issuance as of April 27, 2026, Columbia Financial, Inc. expects to issue approximately 41,800,140 shares of Columbia Financial, Inc. common stock in the merger, assuming the final independent valuation of Columbia Financial is less than $2.3 billion and 30% of the aggregate merger consideration consists of cash. Following the completion of the merger, under such circumstances, former holders of Northfield Bancorp common stock will own approximately 15.4% and existing holders of Columbia Financial common stock (after giving effect to the conversion) will own approximately 84.6% of the common stock of the surviving corporation at the midpoint of the offering range. Additionally, Steven M. Klein and three other legacy Northfield Bancorp directors will join the Columbia Financial, Inc. board of directors as of the effective time of the merger, and the Columbia Financial, Inc. board of directors will be expanded to 13 directors. Because of this, holders of Columbia Financial common stock may have less influence on the management and policies of the surviving corporation than they now have on the management and policies of Columbia Financial.

The merger will not be completed unless important conditions are satisfied or waived, including approval of the merger by Northfield Bancorp stockholders, approval of the merger and the conversion by Columbia Financial stockholders and depositors, and approval of the conversion by the members of Columbia Bank MHC.

Specified conditions set forth in the merger agreement must be satisfied or waived to complete the merger. If the conditions are not satisfied or, subject to applicable law, waived, the Merger will not occur or will be delayed and each of Columbia Financial or Northfield Bancorp may lose some or all of the intended benefits of the merger. The obligations of Columbia Financial, Inc. and Northfield Bancorp to complete the merger are subject to (i) the approval of the merger agreement by the stockholders of each of Columbia Financial and Northfield Bancorp, (ii) the authorization for listing on the Nasdaq Global Select Market of the shares of Columbia Financial, Inc. common stock that will be issued as merger consideration; (iii) the receipt or provision of all non-governmental notices, consents or waivers by non-governmental third parties, except as would not reasonably be expected to have a material adverse effect on Columbia Financial, Columbia Financial, Inc. or Northfield Bancorp; (iv) the effectiveness of the Registration Statement on Form S-4 with respect to the merger and the absence of any stop order by the SEC suspending such effectiveness; (v) the receipt of all required regulatory approvals, in each case without the imposition of any materially burdensome regulatory condition; (vi) no order, injunction or decree issued by any court or governmental entity or other legal restraint or prohibition preventing the completion of the merger; (vii) the deposit of cash and certificates representing sufficient shares of Columbia Financial, Inc. common stock sufficient to pay the merger consideration; (viii) approval of the conversion by the stockholders of Columbia Financial and by the members of Columbia Bank MHC; (ix) the completion of the conversion; (x) the absence of any event that, individually or in the aggregate, has had or will reasonably be likely to have a material adverse effect on Northfield Bancorp or any of its subsidiaries; (xi) the accuracy of the representations and warranties of Columbia Financial, Inc., Columbia Financial, and Northfield Bancorp contained in the merger agreement, both as of the date of the merger agreement and as of the closing of the merger, subject to the materiality standards provided for in the merger agreement; (xii) the performance in all material respects by Columbia Financial, Inc., Columbia Financial and Northfield Bancorp of their respective obligations, covenants and agreements required to be performed under the merger agreement; and (xii) the receipt by each of the parties of an opinion of legal counsel that the merger will qualify as a “reorganization” within the meaning of Section 368(a) of the Code.

Litigation against Columbia Financial or Northfield Bancorp or the members of Columbia Financial’s or Northfield Bancorp’s board of directors, could prevent or delay the completion of the merger.

Columbia Financial stockholders or Northfield Bancorp stockholders may file lawsuits against Columbia Financial, Northfield Bancorp, and/or the boards of directors of either company in connection with the merger. Such legal proceedings

could delay or prevent the merger from being completed in a timely manner. The existence of litigation related to the merger could affect the likelihood of obtaining the required regulatory and stockholders’ approvals. Moreover, any litigation could be time-consuming and expensive and could divert the attention of Columbia Financial’s and Northfield Bancorp’s management attention away from their regular business and their focus on a successful integration of the two companies. Any lawsuit adversely resolved against Columbia Financial, Northfield Bancorp or members of their respective boards of directors could have a material adverse effect on each company’s business, financial condition and results of operations.

Moreover, one of the conditions to the completion of the merger is the absence of any restraining order, injunction or decree issued by a court of competent jurisdiction or other legal restraint or prohibition preventing the consummation of the merger, and that no governmental authority or regulatory authority of competent jurisdiction shall have enacted, promulgated or enforced any statute, rule, regulation, judgment, decree, injunction or other order prohibiting consummation of the transactions contemplated by the merger agreement or making the merger illegal. Consequently, if a settlement or other resolution is not reached in any lawsuit that is filed or any regulatory proceeding and a claimant secures injunctive or other relief or a governmental authority issues an order or other directive restricting, prohibiting or making illegal the consummation of the transactions contemplated by the merger agreement (including the merger), then such injunctive or other relief may prevent the merger from becoming effective in a timely manner or at all.

The unaudited pro forma condensed combined financial information in this prospectus is presented for illustrative purposes only and is not necessarily indicative of what the surviving corporation’s actual financial condition or results of operations would have been had the merger been completed on the dates indicated. The unaudited pro forma condensed combined financial information reflects adjustments, which are based upon preliminary estimates, to record the Northfield Bancorp identifiable assets acquired and liabilities assumed at fair value and the resulting goodwill recognized. The fair value estimates reflected in this prospectus are preliminary, and final amounts will be based upon the actual consideration and the fair value of the assets and liabilities of Northfield Bancorp as of the date of the completion of the merger. Accordingly, the final acquisition accounting adjustments may differ materially from the pro forma adjustments reflected in this Prospectus. For more information, see “Pro Forma Data.”

Risks Related to Our Lending Activities

Our multifamily and commercial real estate lending practices expose us to increased lending risks and related loan losses.

At December 31, 2025, our multifamily and commercial real estate loan portfolios totaled $4.2 billion, or 50.9% of our total loan portfolio. Our current business strategy is to continue our originations of multifamily and commercial real estate loans. These loans generally expose a lender to greater risk of non-payment and loss than one-to-four family residential mortgage loans because repayment of the loans often depends on the successful operation of the properties and the income stream of the borrowers. These loans involve larger loan balances to single borrowers or groups of related borrowers compared to one-to-four family residential mortgage loans. Further, we may increase our loans to individual borrowers, which would result in larger loan balances. To the extent that borrowers have more than one multifamily or commercial real estate loan outstanding, an adverse development with respect to one loan or one credit relationship could expose us to a significantly greater risk of loss compared to an adverse development with respect to a one-to-four family residential real estate loan. Moreover, if loans that are collateralized by multifamily or commercial real estate properties become troubled and the value of the real estate has been significantly impaired, then we may not be able to recover the full contractual amount of principal and interest that we anticipated at the time we originated the loan, which could cause us to increase our provision for credit losses and adversely affect our earnings and financial condition.

Imposition of limits by the bank regulators on commercial and multifamily real estate lending activities could curtail our growth and adversely affect our earnings.

The OCC, the Federal Deposit Insurance Corporation (the “FDIC”) and the Federal Reserve Board (collectively, the “Agencies”) previously issued joint guidance entitled “Concentrations in Commercial Real Estate Lending, Sound Risk Management Practices” (the “CRE Guidance”). Although the CRE Guidance does not establish specific lending limits, it provides that a bank’s commercial real estate lending exposure could receive increased supervisory scrutiny where total non-owner-occupied commercial real estate loans, including loans secured by apartment buildings, investor commercial real estate, and construction and land loans, represent 300% or more of an institution’s total risk-based capital, and the outstanding balance of the commercial real estate loan portfolio has increased by approximately 50% during the preceding 36 months. The balance of these real estate loans represented 350.9% of Columbia Bank’s total risk-based capital at December 31, 2025, and our commercial real estate loan portfolio increased by 4.5% during the preceding 36 months.

In 2015, the Agencies released a new statement on prudent risk management for commercial real estate lending (the “2015 Statement”). In the 2015 Statement, the Agencies, among other things, indicate the intent to continue “to pay special attention” to commercial real estate lending activities and concentrations going forward. If the OCC, our primary federal regulator, were to impose restrictions on the amount of commercial real estate loans we can hold in our portfolio, for reasons noted above or otherwise, our earnings would be adversely affected.

Following completion of the merger of Northfield Bank into Columbia Bank, on a pro forma basis, at December 31, 2025, commercial real estate loans would represent approximately 269% and 212% of Columbia Bank’s total risk-based capital at the adjusted minimum and midpoint of the offering range, respectively.

Our origination of construction loans exposes us to increased lending risks.

We originate commercial construction loans, including speculative construction loans, primarily to professional builders for the construction and acquisition of personal residences, apartment buildings, retail, industrial/warehouse, office buildings and special purpose facilities. Speculative construction loans are loans made to builders who have not identified a buyer for the completed property at the time of loan origination. At December 31, 2025, $469.4 million, or 5.7%, of our loan portfolio, consisted of construction loans, of which $218.4 million or 46.5% consisted of speculative construction loans. In addition, we originate residential construction loans primarily on a construction-to-permanent basis with such loans converting to an amortizing loan following the completion of the construction phase. Our construction loans present a greater level of risk than loans secured by improved, occupied real estate due to: (1) the increased difficulty at the time the loan is made of estimating the building costs and the selling price of the property to be built; (2) the increased difficulty and costs of monitoring the loan; (3) the higher degree of sensitivity to increases in market rates of interest; and (4) the increased difficulty of working out loan problems. In addition, with respect to speculative construction loans, repayment often depends on the successful construction or development and ultimate sale of the property and, possibly, unrelated cash needs of the borrowers. Further, construction costs may exceed original estimates as a result of increased materials, labor or other costs. Construction loans also often involve the disbursement of funds with repayment dependent, in part, on the success of the project and the ability of the borrower to sell or lease the property or refinance the indebtedness.

Our concentration of residential mortgage loans exposes us to increased lending risks.

At December 31, 2025, $2.6 billion or 31.0%, of our loan portfolio was secured by one-to-four family real estate, a significant majority of which is located in the State of New Jersey, and to a lesser extent New York and Pennsylvania. One-to-four family residential mortgage lending is generally sensitive to regional and local economic conditions that significantly impact the ability of borrowers to meet their loan payment obligations, making loss levels difficult to predict. A decline in residential real estate values as a result of a downturn in the local housing market or in the markets in neighboring states in which we originate residential mortgage loans could reduce the value of the real estate collateral securing these types of loans. Declines in real estate values could cause some of our residential mortgages to be inadequately collateralized, which would expose us to a greater risk of loss if we seek to recover on defaulted loans by selling the real estate collateral.

Our commercial business lending activities expose us to additional lending risks.

We make commercial business loans in our market area to a variety of professionals, sole proprietorships, partnerships and corporations. Unlike residential mortgage loans, which generally are made on the basis of the borrower’s ability to make repayment from his or her employment or other income, and which are secured by real property, the value of which tends to be more easily ascertainable, commercial business loans are of higher risk and typically are made on the basis of the borrower’s ability to make repayment from the cash flow of the borrower’s business. As a result, the availability of funds for the repayment of commercial business loans may depend substantially on the success of the business itself. Further, any collateral securing such loans may depreciate over time, may be difficult to appraise, may fluctuate in value and may depend on the borrower’s ability to collect receivables. We have increased our focus on commercial business lending in recent years and intend to continue to focus on this type of lending in the future.

If our allowance for credit losses is not sufficient to cover actual loan losses, our results of operations would be negatively affected.

In determining the amount of the allowance for credit losses, we evaluate loans individually and establish credit loss allowances for specifically identified impairments. For loans not individually analyzed, we estimate losses and establish reserves based on reasonable and supportable forecasts and adjustments for qualitative factors. If the assumptions used in our calculated methodology are inaccurate, our allowance of credit losses may not be sufficient to cover losses inherent in our loan portfolio, which may require additions to our allowance and may decrease our net income. Our emphasis on commercial loan growth and on increasing our portfolio, as well as any future credit deterioration, will require us to increase our allowance further in the future.

In addition, our banking regulators periodically review our allowance for credit losses and may require us to increase our provision for credit losses. Any increase in our allowance for credit losses or loan charge-offs as required by regulatory authorities may have a material adverse effect on our results of operations and financial condition.

The geographic concentration of our loan portfolio and lending activities makes us vulnerable to a downturn in the New Jersey and metropolitan New York and Philadelphia economies.

While there is not a single employer or industry in our market area on which a significant number of our customers are dependent, a substantial portion of our loan portfolio is comprised of loans secured by property located throughout New Jersey and in metropolitan New York and Philadelphia. In addition, following the completion of our merger with Northfield Bancorp, a significant portion of the combined company’s loan portfolio will also be comprised of loans secured by property located in Staten Island and Brooklyn. This makes us vulnerable to a downturn in the regional economy and real estate markets. Adverse conditions in the local economy such as unemployment, recession, a catastrophic event or other factors beyond our control could impact the ability of our borrowers to repay their loans, which could impact our net interest income. Decreases in regional real estate values caused by economic conditions, recent changes in tax laws or other events could adversely affect the value of the property used as collateral for our loans, which could cause us to realize a loss in the event of a foreclosure. Further, deterioration in regional economic conditions could drive the level of loan losses beyond the level we have provided for in our allowance for credit losses, which in turn could necessitate an increase in our provision for credit losses and a resulting reduction to our earnings and capital.

Economic conditions could result in increases in our level of non-performing loans and/or reduce demand for our products and services, which could have an adverse effect on our results of operations.

Prolonged deteriorating economic conditions could significantly affect the markets in which we do business, the value of our loans and securities, and our ongoing operations, costs and profitability. Further, declines in real estate values and sales volumes and elevated unemployment levels may result in higher loan delinquencies, increases in our non-performing and classified assets and a decline in demand for our products and services. These events may cause us to incur losses and may adversely affect our financial condition and results of operations. Reduction in problem assets can be slow, and the process can be exacerbated by the condition of the properties securing non-performing loans and lengthy foreclosure processes. To the extent that we must work through the resolution of assets, economic problems may cause us to incur losses and adversely affect our capital, liquidity, and financial condition.

Northfield Bancorp’s New York multifamily loan portfolio may continue to be adversely affected by changes in legislation or regulation.

At the effective time of the merger, we will acquire Northfield Bancorp and its loan portfolio. At December 31, 2025, Northfield Bancorp had approximately $418.8 million of New York multifamily loans that have some form of rent stabilization or rent control. Pro forma for the merger, this portfolio will initially represent 3.5% of our total loan portfolio. In 2019, the New York State legislature passed the Housing Stability and Tenant Protection Act of 2019, impacting about one million rent regulated apartment units. Among other things, the legislation: (i) curtails rent increases from material capital improvements and individual apartment improvements; (ii) all but eliminates the ability for apartments to exit rent regulation; (iii) does away with vacancy decontrol and high-income deregulation; and (iv) repealed the 20% vacancy bonus. This legislation generally limits a landlord’s ability to increase rents on rent-regulated apartments and makes it more difficult to convert rent regulated apartments to market rate apartments. For example, the New York City Rent Guidelines Board established that on certain apartments, for a one-year lease beginning on or after September 30, 2024, the maximum rent increase is 3.0%, even when the overall inflation rate has increased at a higher rate.

The recent election of Zohran Mamdani as Mayor of New York City introduces potential policy changes that could affect the city’s multifamily housing market. The administration has expressed support for rent freezes and expanded tenant protections, which, if enacted, may reduce rental income and property values across multifamily properties. These market dynamics could adversely impact the credit quality of our borrowers. Lower property cash flows may impair borrowers’ ability to service existing debt. In addition, a sustained decline in collateral values could elevate loan-to-value ratios and reduce recovery prospects in the event of foreclosure.

Risks Related to Our Growth Strategies

Our business strategy includes growth in assets and deposits and the scale of our operations. Achieving such growth will require us to attract customers that currently bank at other financial institutions in our market area. Our ability to successfully

grow will depend on a variety of factors, including our ability to attract and retain experienced bankers, the continued availability of desirable business opportunities, competition from other financial institutions in our market area and our ability to manage our growth. Growth opportunities may not be available, or we may not be able to manage our growth successfully. If we do not manage our growth effectively, our financial condition and operating results could be negatively affected. Furthermore, there can be considerable costs involved in expanding deposit and lending capacity that generally require a period of time to generate the necessary revenues to offset their costs, especially in areas in which we do not have an established presence and that require alternative delivery methods. Accordingly, any such business expansion can be expected to negatively impact our earnings for some period of time until certain economies of scale are reached. Our expenses could be further increased if we encounter delays in modernizing existing facilities, opening new branches or deploying new services.

We are subject to certain risks in connection with our strategy of growing through mergers and acquisitions.

Mergers and acquisitions are currently a component of our business model and growth strategy. Since 2019, we have acquired Atlantic Stewardship Bank, Roselle Bank, Freehold Bank and RSI Bank. It is possible that we could acquire other banking institutions following our acquisition of Northfield Bancorp, other financial services companies or branches of banks in the future. Acquisitions typically involve the payment of a premium over book and trading values and, therefore, may result in the dilution of our tangible book value per share. Our ability to engage in future mergers and acquisitions depends on various factors, including: (1) our ability to identify suitable merger partners and acquisition opportunities; (2) our ability to finance and complete transactions on acceptable terms and at acceptable prices; and (3) our ability to receive the necessary regulatory and, when required, stockholder approvals. Our inability to engage in an acquisition or merger for any of these reasons could have an adverse impact on the implementation of our business strategies. Furthermore, mergers and acquisitions involve a number of risks and challenges, including (1) our ability to achieve planned synergies and to integrate the branches and operations we acquire, and the internal controls and regulatory functions into our current operations; (2) the integration process could adversely affect our ability to maintain relationships with existing customers; (3) the diversion of management’s attention from existing operations, which may adversely affect our ability to successfully conduct our business and negatively impact our financial results and (4) our ability to identify potential asset quality issues or contingent liabilities during the due diligence process.

We may be required to write down goodwill and other acquisition-related identifiable intangible assets.

When we acquire a business, a portion of the purchase price of the acquisition typically is allocated to goodwill and other identifiable intangible assets. The excess of the purchase price over the fair value of the net identifiable tangible and intangible assets acquired determines the amount of the purchase price that is allocated to goodwill acquired. As of December 31, 2025, goodwill and other identifiable intangible assets were $117.7 million. Under current accounting guidance, if we determine that goodwill or intangible assets are impaired, we would be required to write down the value of these assets. We conduct an annual review to determine whether goodwill and other identifiable intangible assets are impaired. We conduct a quarterly review for indicators of impairment of goodwill and other identifiable intangible assets. Our management recently completed these reviews and concluded that no impairment charge was necessary for the year ended December 31, 2025. We cannot provide assurance whether we will be required to take an impairment charge in the future. Any impairment charge would have a negative effect on our stockholders’ equity and financial results and may cause a decline in our stock price.

Risks Related to Our Business and Industry Generally

Ineffective liquidity management could adversely affect our financial results and condition.

Effective liquidity management is essential for the operation of our business. We require sufficient liquidity to meet customer loan requests, customer deposit maturities/withdrawals, payments on our debt obligations as they come due and other cash commitments under both normal operating conditions and other unpredictable circumstances causing industry or general financial market stress. Our access to funding sources in amounts adequate to finance our activities on terms that are acceptable to us could be impaired by factors that affect us specifically or the financial services industry or economy generally. Factors that could detrimentally impact our access to liquidity sources include a downturn in the geographic markets in which our loans and operations are concentrated or difficult credit markets. Our access to deposits may also be affected by the liquidity needs of our depositors. In particular, a majority of our liabilities are checking accounts and other liquid deposits, which are payable on demand or upon several days’ notice, while by comparison, a substantial majority of our assets are loans, which cannot be called or sold in the same time frame. Although we have historically been able to replace maturing deposits and advances as necessary, we might not be able to replace such funds in the future, especially if a large number of our depositors seek to withdraw their accounts, regardless of the reason. A failure to maintain adequate liquidity could materially and adversely affect our business, results of operations or financial condition.

Changes in interest rates or the shape of the yield curve may hurt our profits and asset values and our strategies for managing interest rate risk may not be effective.

We are subject to significant interest rate risk as a financial institution with a high percentage of fixed rate loans and certificates of deposit on our balance sheet. Our interest-bearing liabilities reprice or mature more quickly than our interest-earning assets. Changes in the general level of interest rates can affect our net interest income by affecting the difference between the weighted-average yield earned on our interest-earning assets and the weighted-average rate paid on our interest-bearing liabilities, or interest rate spread, and the average life of our interest-earning assets and interest-bearing liabilities. Changes in interest rates also can affect: (1) our ability to originate loans; (2) the value of our interest-earning assets and our ability to realize gains from the sale of such assets; (3) our ability to obtain and retain deposits in competition with other available investment alternatives; and (4) the ability of our borrowers to repay their loans, particularly adjustable or variable rate loans. Interest rates are highly sensitive to many factors, including government monetary policies, domestic and international economic and political conditions and other factors beyond our control.

The fair value of our investments has declined materially in the past and could decline further due to a variety of factors.

Most of our investment securities portfolio is designated as available-for-sale. Accordingly, unrealized gains and losses, net of tax, in the estimated fair value of the available-for-sale portfolio is recorded as other comprehensive income, a separate component of stockholders’ equity. Due to increases in interest rates in 2022 and 2023, the fair value of our investment portfolio declined, causing a corresponding decline in stockholders’ equity. Future increases in interest rates could lead to a corresponding decline in stockholders’ equity. Management believes that several factors will affect the fair values of the investment portfolio, including, but not limited to, changes in interest rates or expectations of changes, the degree of volatility in the securities markets, inflation rates or expectations of inflation and the slope of the interest rate yield curve. In addition, any adverse development in the factors used to assess credit related impairment could require us to recognize an impairment in the value of our investment securities portfolio, which could have an adverse effect on our results of operations in future periods

Financial challenges at other banking institutions could lead to depositor concerns that spread within the banking industry causing disruptive and destabilizing deposit outflows.

In 2023, Silicon Valley Bank and Signature Bank experienced large deposit outflows coupled with insufficient liquidity to meet withdrawal demands, resulting in the institutions being placed into Federal Deposit Insurance Corporation (“FDIC”) receivership. Additionally, in 2023, First Republic Bank experienced similar circumstances which resulted in the institution being placed in FDIC receivership. In the aftermath of these events, there has been substantial market disruption and concerns that diminished depositor confidence could spread across the banking industry, leading to deposit outflows that could destabilize other institutions. To strengthen public confidence in the banking system, the FDIC took action to protect funds held in uninsured deposit accounts at Silicon Valley Bank and Signature Bank following the placement of those institutions into receivership. However, the FDIC has not committed to protecting uninsured deposits in other institutions that experience outsized withdrawal demands. At December 31, 2025, the aggregate amount of our uninsured deposits (deposits in amounts greater than or equal to $250,000, which is the maximum amount for federal deposit insurance) was $3.3 billion. This amount included municipal deposits of $944.6 million, which are collateralized, and intercompany deposits of $42.6 million. At December 31, 2025, we had approximately $3.1 billion in available liquidity, including $340.8 million in cash and cash equivalents, which was sufficient to cover the majority of our uninsured deposits. Notwithstanding our significant liquidity, large deposit outflows could adversely affect our financial condition and results of operations and could result in the closure of Columbia Bank. Furthermore, the recent bank failures may result in strengthening of capital and liquidity rules which, if the revised rules apply to us, could adversely affect our financial condition and results of operations.

Municipal deposits are an important source of funds for us and a reduced level of such deposits may hurt our profits.

Municipal deposits are an important source of funds for our lending and investment activities. At December 31, 2025, $1.0 billion, or 11.6% of our total deposits were comprised of municipal deposits, including public funds deposits from local government entities primarily domiciled in the State of New Jersey. Given our use of these high-average balance municipal deposits as a source of funds, our inability to retain such funds could have an adverse effect on our liquidity. In addition, our municipal deposits are primarily demand deposit accounts or short-term deposits and therefore are more sensitive to changes in interest rates. If we are forced to pay higher rates on our municipal deposits to retain those funds, or if we are unable to retain those funds and we are forced to turn to borrowing sources for our lending and investment activities, the interest expense associated with such borrowings may be higher than the rates we are paying on our municipal deposits, which could adversely affect our net income. On a pro forma basis, following our acquisition of Northfield Bancorp, our combined municipal deposits would be $2.0 billion, or approximately 16.1% of our total deposits, at December 31, 2025.

Our business is dependent on the successful and uninterrupted functioning of our information technology and telecommunications systems and third-party service providers. The failure of these systems, or the termination of a third-party software license or service agreement on which any of these systems is based, could interrupt our operations. Because our information technology and telecommunications systems interface with and depend on third-party systems, we could experience service denials if demand for such services exceeds capacity, or such third-party systems fail or experience interruptions. If significant, sustained or repeated, a system failure or service denial could compromise our ability to operate effectively, damage our reputation, result in a loss of customer business, and/or subject us to additional regulatory scrutiny and possible financial liability, any of which could have a material adverse effect on us.

Our third-party service providers may be vulnerable to unauthorized access, computer viruses, phishing schemes and other security breaches. We likely will expend additional resources to protect against the threat of such security breaches and computer viruses, or to alleviate problems caused by such security breaches or viruses. To the extent that the activities of our third-party service providers or the activities of our customers involve the storage and transmission of confidential information, security breaches and viruses could expose us to claims, regulatory scrutiny, litigation costs and other possible liabilities.

Security breaches and cybersecurity threats could compromise our information and expose us to liability, which would cause our business and reputation to suffer.

In the ordinary course of our business, we collect and store sensitive data, including our proprietary business information and that of our customers, suppliers and business partners, as well as personally identifiable information about our customers and employees. The secure processing, maintenance and transmission of this information is critical to our operations and business strategy. We, our customers, and other financial institutions with which we interact, are subject to ongoing, continuous attempts to penetrate key systems by individual hackers, organized criminals, and in some cases, state-sponsored organizations.

While we have established policies and procedures to prevent or limit the impact of cyber attacks, there can be no assurance that such events will not occur or will be adequately addressed if they do. In addition, we also outsource certain cybersecurity functions, such as penetration testing to third party service providers, and the failure of these service providers to adequately perform such functions could increase our exposure to security breaches and cybersecurity threats. Despite our security measures, our information technology and infrastructure may be vulnerable to attacks by hackers or breached due to employee error, malfeasance or other malicious code and cyber attacks that could have an impact on information security. Any such breach or attacks could compromise our networks and the information stored could be accessed, publicly disclosed, lost or stolen. Any such unauthorized access, disclosure or other loss of information could result in legal claims or proceedings, liability under laws that protect the privacy of personal information, and regulatory penalties; disrupt our operations and the services we provide to customers; damage our reputation; and cause a loss of confidence in our products and services, all of which could adversely affect our financial condition and results of operations.

We must keep pace with technological change to remain competitive.

Financial products and services have become increasingly technology-driven. Our ability to meet the needs of our customers competitively, and in a cost-efficient manner, is dependent on the ability to keep pace with technological advances and to invest in new technology as it becomes available, as well as related essential personnel. In addition, technology has lowered barriers to entry into the financial services market and made it possible for financial technology companies and other non-bank entities to offer financial products and services traditionally provided by banks. The ability to keep pace with technological change is important, and the failure to do so, due to cost, proficiency or otherwise, could have a material adverse impact on our business and therefore on our financial condition and results of operations.

Our business may be materially affected by the emergence of disruptive new technologies or approaches enabled by the rapid pace of innovation unfolding in the artificial intelligence space.

The safe and responsible integration of artificial intelligence, or “AI,” functionality as it rapidly evolves presents emerging ethical and legal challenges, and the use of such technologies may result in diminished brand trust and reputational harm. As with many innovations, AI presents risks and challenges that could significantly disrupt our business model. In addition, the use of AI by bad actors presents increasingly complex and sophisticated security threats to our confidential customer and employee data as well as confidential data of our company, and we must make additional efforts to maintain network security.

The regulatory landscape surrounding AI technologies is evolving, and the ways in which these technologies will be regulated by governmental authorities, self-regulatory institutions, or other regulatory authorities remains uncertain and may be inconsistent from jurisdiction to jurisdiction. Certain jurisdictions in which we operate are considering or have proposed or enacted legislation and policies regulating AI and non-personal data. Such regulations may result in operational costs to modify, maintain, or align our business practices, or constrain our ability to develop, deploy, or maintain these technologies.

Because the nature of the financial services business involves a high volume of transactions, we face significant operational risks.

We operate in diverse markets and rely on the ability of our employees and systems to process a high number of transactions. Operational risk is the risk of loss resulting from our operations, including but not limited to, the risk of fraud by employees or outside persons, the execution of unauthorized transactions by employees, errors relating to transaction processing and technology, breaches of our internal control system and compliance requirements, and business continuation and disaster recovery. Insurance coverage may not be available for such losses, or where available, such losses may exceed insurance limits. This risk of loss also includes the potential legal actions that could arise as a result of an operational deficiency or as a result of noncompliance with applicable regulations, adverse business decisions or their implementation, and customer attrition due to potential negative publicity. Although our control testing has not identified any significant deficiencies in our internal control system, a breakdown in our internal control system, improper operation of our systems or improper employee actions could result in material financial loss to us, the imposition of regulatory action, and damage to our reputation.

The building of market share through our branch office strategy, and our ability to achieve profitability on new branch offices, may increase our expenses and negatively affect our earnings.

We believe there are branch expansion opportunities within our market area and adjacent markets, including other states, and we will seek to grow our deposit base by adding branches to our existing branch network. There are considerable costs involved in opening branch offices, especially in light of the capabilities needed to compete in today’s environment. Moreover, new branch offices generally require a period of time to generate sufficient revenues to offset their costs, especially in areas in which we do not have an established presence. Accordingly, new branch offices could negatively impact our earnings and may do so for some period of time. Our investments in products and services, and the related personnel required to implement new policies and procedures, take time to earn returns and can be expected to negatively impact our earnings for the foreseeable future. The profitability of our expansion strategy will depend on whether the income that we generate from the new branch offices will offset the increased expenses resulting from operating these branch offices.

Strong competition within our market area could hurt our profits and slow growth.

Our profitability depends upon our continued ability to compete successfully in our market area. We face intense competition both in making loans and attracting deposits. We continue to face stiff competition for one-to-four family residential loans from other financial service providers, including large national residential lenders and local community banks. Other competitors for one-to-four family residential loans include credit unions and mortgage brokers which keep overhead costs and mortgage rates down by selling loans and not holding or servicing them. Our competitors for commercial real estate and multifamily loans include other community banks, commercial lenders and insurance companies, some of which are larger than us and have greater resources and lending limits than we have and offer services that we do not provide, along with government agencies such as the Federal Home Loan Mortgage Corporation (“Freddie Mac”), the Federal National Mortgage Association (“Fannie Mae”) and the Government National Mortgage Association (“Ginnie Mae”). Price competition for loans and deposits might result in us earning less on our loans and paying more on our deposits, which reduces net interest income. We expect competition to remain strong in the future.

In addition, competition with non-banks, including technology companies, to provide financial products and services is intensifying. In particular, the activity of fintechs has grown significantly over recent years and is expected to continue to grow. Fintechs have and may continue to offer bank or bank-like products. Federal and state bank regulatory agencies have demonstrated a willingness to charter non-traditional bank charter applicants, such as fintechs, which increases competition in the industry. In addition, other fintechs, through commercials relationships with existing banks, in effect offer deposit products to their customers under current and proposed interagency guidelines on third-party relationships. In addition to fintechs, the large technology companies have begun to make efforts toward providing financial services directly to their customers and are expected to continue to explore new ways to do so. Many of these companies, including our competitors, have fewer regulatory constraints, and some have lower cost structures, in part due to lack of physical locations and regulatory compliance costs. Some of these companies also have greater resources to invest in technological improvements than we currently have.

Acts of terrorism and other external events could impact our ability to conduct business.

Financial institutions have been and continue to be targets of terrorist threats aimed at compromising operating and communication systems. Additionally, the metropolitan New York area and northern New Jersey remain central targets for potential acts of terrorism. Such events could cause significant damage, impact the stability of our facilities and result in additional expenses, impair the ability of our borrowers to repay their loans, reduce the value of collateral securing repayment of our loans, and result in the loss of revenue. The occurrence of any such event could have a material adverse effect on our business, operations and financial condition.

Climate change, severe weather, global pandemics, natural disasters, and other external events could significantly impact our business.

Natural disasters, including severe weather events, global pandemics, and other adverse external events could have a significant impact on our ability to conduct business or upon third parties who perform operational services for us. Such events could affect the stability of our deposit base, impair the ability of borrowers to repay outstanding loans, impair the value of collateral securing loans, cause significant property damage, result in lost revenue, or cause us to incur additional expenses.

Rapidly evolving economic, social and political conditions or civil unrest in the United States, may affect the markets in which we operate, our customers, our ability to provide customer service, and could have a material adverse impact on our business, results of operations, or financial condition.

Our business may be adversely affected by instability, disruption or destruction in the markets in which we operate, regardless of cause, including tariffs, government shutdowns, war, terrorism, riot, civil insurrection or social unrest, and natural or man-made disasters, including storms, or other events beyond our control. Such events can increase levels of political and economic unpredictability, result in property damage and business closures within our markets and increase the volatility of the financial markets. Any of these effects could have a material and adverse impact on our business and results of operations. These events also pose significant risks to Columbia Financial’s personnel and to physical facilities, transportation and operations, which could materially adversely affect Columbia Financial’s financial results.

Regulation of the financial services industry is intense, and we may be adversely affected by changes in laws and regulations.

We are subject to extensive government regulation, supervision and examination. Such regulation, supervision and examination govern the activities in which we may engage and are intended primarily for the protection of the federal deposit insurance fund and Columbia Bank’s depositors. Any future legislative or regulatory changes could have a material impact on our profitability, the value of assets held for investment or the value of collateral for loans. Future legislative changes could also require changes to business practices and potentially expose us to additional costs, liabilities, enforcement action and reputational risk. Federal regulatory agencies also have the ability to take strong supervisory actions against financial institutions that have experienced increased loan production and losses and other underwriting weaknesses or have compliance weaknesses. These actions include entering into formal or informal written agreements and cease and desist orders that place certain limitations on their operations, and/or they can impose fines. If we were to become subject to a regulatory action, such action could negatively impact our ability to execute our business plan, and result in operational restrictions, as well as our ability to grow, pay dividends, repurchase stock or engage in mergers and acquisitions. See “—Regulation and Supervision — Federal Banking Regulations-Capital Requirements” for a discussion of regulatory capital requirements.

We may be unable to disclose some regulatory restrictions or limitations on our operations imposed by our regulators, even if material to our business.

As part of our regular examination process, our regulators may advise us to operate under various restrictions as a prudential matter. Any such actions or restrictions, if and in whatever manner imposed, could adversely affect our costs and revenues. Moreover, efforts to comply with any such nonpublic supervisory actions or restrictions may require material investments in additional resources and systems, as well as a significant commitment of managerial time and attention. As a result, such supervisory actions or restrictions, if and in whatever manner imposed, could have a material adverse effect on our business and results of operations; and, in certain instances, we may not be able to publicly disclose these matters, even if material to our business.

As a larger financial institution, we are subject to additional regulation and increased supervision.

Columbia Financial’s assets totaled $11.0 billion as of December 31, 2025. Financial institutions with assets in excess of $10 billion are subject to requirements imposed by the Dodd-Frank Act and its implementing regulations including being

subject to the examination authority of the Consumer Financial Protection Bureau to assess our compliance with federal consumer financial laws, the imposition of higher FDIC premiums, reduced debit card interchange fees, and enhanced risk management frameworks, all of which increase operating costs and reduce earnings. We have been subject to such requirements since 2022.

As we continue to grow in size through our acquisition of Northfield Bancorp and through organic growth, we can expect greater regulatory scrutiny and expectations requiring us to invest significant management attention and make additional investments in staff and other resources to comply with applicable regulatory expectations. While we cannot predict what effect any presently contemplated or future changes in the laws or regulations or their interpretations may have on us, these changes could be material. The increased regulatory costs resulting from Columbia Financial being a larger financial institution may negatively impact Columbia Financial’s revenue and earnings.

Changes resulting from updated regulations and laws could include increased regulatory oversight, higher capital requirements or changes in the way regulatory capital is calculated, and the impositions of additional restrictions through regulatory changes or supervisory or enforcement activities, each of which could have a material impact on our business.

We face significant legal risks, both from regulatory investigations and proceedings, and from potential private actions brought against us.

As a financial services company, many aspects of our business involve substantial risk of legal liability. From time to time, customers and others make claims and take legal action pertaining to the performance of our responsibilities. In addition, at any given time, we are involved in a number of legal and regulatory examinations and investigations as a part of reviews conducted by regulators and other parties, which may involve banking, securities, consumer protection, employment, tort, and numerous other laws and regulations. Whether customer claims or legal and/or regulatory action related to the performance of our responsibilities are founded or unfounded, they may result in significant expenses, attention from management and financial liability, even if they are resolved in a manner favorable to us. Any financial liability or reputational damage could have a material adverse effect on our business, which, in turn, could have a material adverse effect on our financial condition and results of operations. There is no assurance that litigation with private parties will not increase in the future. In addition, regulatory actions or investigations may result in judgments, settlements, fines, penalties or other results adverse to us, which could materially adversely affect our business, financial condition or results of operations, or cause reputational harm to us.

As a bank with strong local and community relationships, our reputation is a valuable component of our business. A key component of our business strategy is to rely on our reputation for customer service and knowledge of local markets to expand our presence by capturing new business opportunities in our market area. We strive to conduct our business in a manner that enhances our reputation. This is done, in part, by recruiting, hiring and retaining employees who share our core values of being an integral part of the communities we serve, delivering superior service to our customers and caring about our customers and associates. If our reputation is negatively affected by the actions of our employees, by our inability to conduct our operations in a manner that is appealing to current or prospective customers, or by events beyond our control, our business and operating results may be adversely affected.

Threats to our reputation can come from many sources, including adverse sentiment about financial institutions generally, the perception of unethical practices, employee misconduct, failure to deliver minimum standards of service or quality, compliance deficiencies, cybersecurity breaches and questionable or fraudulent activities of our customers. We have policies and procedures in place to protect our reputation and promote ethical conduct, but these policies and procedures may not be fully effective. Negative publicity regarding our business, employees, or customers, with or without merit, may result in the loss of customers and employees, costly litigation and increased governmental regulation, all of which could adversely affect our operating results.

Social media may exacerbate the risk of negative publicity, including by amplifying and accelerating the dissemination of rumors and disinformation. The Financial Stability Board, an international body that monitors and makes recommendations about the global financial system, released a report in October 2024 acknowledging the potential for social media to facilitate or accelerate deposit runs through the propagation of information, including rumors or false information. In its report, the Financial Stability Board noted that the repetition of information in social media, which users experience through the re-posting or liking of other individuals’ posts, can reinforce a message and may make the message more believable.

We are subject to environmental, social and governance risks that could adversely affect our reputation and the trading price of our common stock.

We are subject to a variety of environmental, social and governance risks that arise out of the set of concerns that together comprise what have become commonly known as “ESG matters.” Risks arising from ESG matters may adversely affect, among other things, our reputation and the trading price of our common stock.

We have multiple stakeholders, among them stockholders, customers, employees, federal and state regulatory authorities, and political entities. Often those stakeholders have differing, and sometimes conflicting, priorities and expectations regarding ESG issues. In addition, certain federal and state laws and regulations related to ESG issues may include provisions that conflict with other laws and regulations, which may increase our costs or limit our ability to conduct business in certain jurisdictions. For example, there is an increasing number of state-level anti-ESG initiatives in the U.S. that may conflict with other regulatory requirements or our various stakeholders’ expectations. In addition, beginning in 2025, corporate diversity, equity and inclusion practices have come under increasing scrutiny and the current Administration issued a number of executive orders, including orders focused on affirmative action programs of federal contractors, which indicate increased scrutiny of diversity, equity and inclusion initiatives at private, non-governmental entities, including publicly traded companies.

The federal executive branch agencies are expected to continue their focus on such programs and policies, including to further define what may constitute an “illegal” program or policy. Such divergent, sometimes conflicting views on ESG-related matters increase the risk that any action or lack thereof by us on such matters will be perceived negatively by some stakeholders. Failing to comply with expectations and standards from investors, customers, regulators, policymakers and other stakeholders regarding ESG-related issues, or taking action in conflict with one or another of those stakeholders’ expectations, could also lead to loss of business, adverse publicity, an adverse impact on our reputation, customer complaints, or public protests.

Any adverse publicity or adverse impact on our reputation in connection with ESG, any shifts in investing priorities among investors, or any loss of business resulting from any of the foregoing, may result in adverse effects on the trading price of our common stock and/or our business, operations and earnings.

Risks Related to the Offering

The future price of the shares of common stock may be less than the $10.00 purchase price per share in the offering.

If you purchase shares of common stock in the offering, you may not be able to sell them later at or above the $10.00 purchase price in the offering. In many cases, shares of common stock issued by newly converted savings institutions or mutual holding companies have traded below the initial offering price. The aggregate purchase price of the shares of common stock sold in the offering will be based on an independent appraisal. The independent appraisal is not intended, and should not be construed, as a recommendation of any kind as to the advisability of purchasing shares of common stock. The independent appraisal is based on certain estimates, assumptions and projections, all of which are subject to material change from time to time. After the shares begin trading, the trading price of our common stock will be determined by the marketplace, and may be influenced by many factors, including prevailing interest rates, the overall performance of the economy, changes in federal tax laws, new federal and/or state laws and regulations, investor perceptions of Columbia Financial, Inc., our success after the merger in integrating the business of Northfield Bancorp, and the outlook for the financial services industry in general. Price fluctuations in our common stock may be unrelated to our operating performance.

Various factors may have an adverse effect on our financial performance.

We intend to contribute 50% of the net proceeds from the offering to Columbia Bank’s capital. The remaining net proceeds from the offering will be used in part to fund a loan to employee stock ownership plan to finance its purchase of shares in the offering (or possibly, after the offering, in open market purchases), approximately $179.1 million will be used to finance the cash portion of the merger consideration at the midpoint of the offering range, and the balance will be retained by Columbia Financial, Inc. We may use the remaining net proceeds to invest in short-term investments and for general corporate purposes, including, subject to regulatory limitations, the repurchase of shares of common stock and the payment of dividends. Columbia Bank may use the net proceeds it receives to fund new loans, expand its retail banking franchise by establishing or acquiring new branches or by acquiring other financial institutions or other financial services companies, or for other general corporate purposes. Except as noted in this prospectus, we have not allocated specific amounts of the net proceeds for any of these purposes, and we will have significant flexibility in determining the amount of the net proceeds we apply to different uses and when we apply or reinvest such proceeds. We have not established a timetable for reinvesting the net proceeds, and we cannot predict how long we will be required to reinvest the net proceeds. Our failure to utilize these funds effectively would reduce our profitability and may adversely affect the value of our common stock.

Our return on equity may be low following the offering, which could negatively affect the trading price of our shares of common stock.

Net income divided by average stockholders’ equity, known as “return on equity,” is a ratio many investors use to compare the performance of financial institutions. Our return on equity may be low until we are able to leverage the additional capital we receive from the offering. Our return on equity will be negatively affected by added expenses associated with our employee stock ownership plan and the stock-based benefit plans we intend to adopt after the offering. Until we can increase our net interest income and non-interest income, achieve cost efficiency in the merger and leverage the capital raised in the offering, we expect our return on equity to be low, which may reduce the market price of our shares of common stock.

Our stock-based benefit plans will increase our expenses and reduce our income.

We intend to adopt one or more new stock-based benefit plans after the conversion and the offering, subject to stockholder approval, which will increase our annual compensation and benefit expenses related to the stock options and stock awards granted to participants under the new stock-based benefit plans. The actual amount of these new stock-related compensation and benefit expenses will depend on the number of options and stock awards actually granted under the plans, the fair market value of our stock or options on the date of grant, the vesting period, and other factors which we cannot predict at this time. In the event we adopt stock-based benefit plans within 12 months following the conversion, the total shares of common stock reserved for issuance pursuant to awards of restricted stock and grants of options under such plans would be limited to 2.45% and 6.20%, respectively, of the total shares of our common stock sold in the offering. If we award restricted shares of common stock or grant options in excess of these amounts under stock-based benefit plans adopted more than 12 months after the completion of the conversion, our costs would increase further.

In addition, we will recognize compensation expense for our employee stock ownership plan when shares are committed to be released to participants’ accounts, and we will recognize compensation expense for restricted stock awards and stock options over the vesting period of awards made to recipients. We anticipate that in the first full fiscal year following the offering, our incremental compensation expense for employee stock ownership plan (“ESOP”) shares purchased in the offering and for our new stock-based benefit plans will significantly increase our overall compensation expense as compared to 2025. For further discussion of our proposed stock-based plans, please refer to the section of this prospectus titled “Executive and Director Compensation—Benefits to be Considered Following Completion of the Offering.”

The implementation of stock-based benefit plans may dilute your ownership interest.

One or more new stock-based benefit plans that we adopt following the offering may be funded either through open market purchases or from the issuance of authorized but unissued shares of common stock. Our ability to repurchase shares of common stock to fund these plans will be subject to many factors, including applicable regulatory restrictions on stock repurchases, the availability of stock in the market, the trading price of the stock, our capital levels, alternative uses for our capital and our financial performance. Although our intention is to fund the new stock-based benefit plans through open market purchases, stockholders would experience a 5.16% dilution in ownership interest at the maximum of the offering range in the event newly issued shares of our common stock are used to fund stock options and shares of restricted common stock in amounts equal to 6.20% and 2.45%, respectively, of the shares sold in the offering. In the event we adopt the plans more than 12 months following the conversion, new stock-based benefit plans would not be subject to these limitations, and stockholders could experience greater dilution.

Although the implementation of new stock-based benefit plans would be subject to stockholder approval, historically, the overwhelming majority of stock-based benefit plans adopted by banks and their holding companies following mutual-to-stock conversions have been approved by stockholders.

We currently expect that the number of shares available for grants of common stock and stock options will not exceed 2.45% and 6.20%, respectively, of the number of shares of common stock sold in the offering, regardless of when those plans are adopted. If, however, we adopt stock-based benefit plans more than 12 months following the completion of the offering, we would be permitted under applicable regulations to adopt equity plans under which we could grant shares of common stock or stock options exceeding these amounts. If we adopt stock-based benefit plans that provide for awards in excess of these amounts, our expenses associated with those plans would exceed the amounts estimated in the section of this prospectus titled “Pro Forma Data.” Stock-based benefit plans that provide for awards in excess of these amounts could also result in dilution to stockholders in excess of that described in the section of this prospectus titled “Executive and Director Compensation — Benefits to be Considered Following Completion of the Offering.” Although the implementation of stock-based benefit plans would be subject to stockholder approval, the timing of the implementation of such plans will be at the discretion of our board of directors.

Various factors may make takeover attempts more difficult to achieve.

Certain provisions of our articles of incorporation and bylaws and state and federal banking laws, including regulatory approval requirements, could make it more difficult for a third party to acquire control of Columbia Financial, Inc. without our board of directors’ approval. Under regulations applicable to the conversion, for a period of three years following completion of the conversion, no person may offer to acquire or acquire beneficial ownership of more than 10% of our common stock without the prior approval of the Federal Reserve Board. Under federal law, subject to certain exemptions, a person, entity or group must obtain the approval of the Federal Reserve Board before acquiring control of a savings and loan company. There are also provisions in our articles of incorporation and bylaws that we may use to delay or block a takeover attempt, including a provision that prohibits any person from voting more than 10% of our outstanding shares of common stock. Furthermore, shares of restricted stock and stock options that we may grant to employees and directors, stock ownership by our management and directors, including through our employee stock ownership plan, and other factors may make it more difficult for companies or persons to acquire control of Columbia Financial, Inc. without the consent of our board of directors. Taken as a whole, these statutory provisions and provisions in our articles of incorporation and bylaws could result in our being less attractive to a potential acquirer and thus could adversely affect the market price of our common stock. For additional information, see “Restrictions on Acquisition of Columbia Financial, Inc.”

The bylaws of Columbia Financial, Inc. provide that, unless Columbia Financial, Inc. consents in writing to the selection of an alternative forum, the sole and exclusive forum for (i) any derivative action or proceeding brought on behalf of Columbia Financial, Inc. (ii) any action asserting a claim of breach of a fiduciary duty owed to Columbia Financial, Inc.’s or Columbia Financial, Inc.’s stockholders, by any director, officer or other employee of Columbia Financial, Inc. (iii) any action asserting a claim arising pursuant to any provision of Maryland General Corporation Law, or (iv) any action asserting a claim governed by the internal affairs doctrine shall be a state or federal court located within the State of Maryland. This exclusive forum provision does not apply to claims arising under the federal securities laws. This exclusive forum provision may limit a stockholder’s ability to bring a claim in a judicial forum it believes is more favorable for disputes with Columbia Financial, Inc. and its directors, officers, and other employees or may cause a stockholder to incur additional expense by having to bring a claim in a judicial forum that is distant from where the stockholder resides, or both. In addition, if a court were to find this exclusive forum provision to be inapplicable or unenforceable in a particular action, we may incur additional costs associated with resolving the action in another jurisdiction, which could have a material adverse effect on our financial condition and results of operations.

The market price of our stock value may be negatively affected by applicable regulations that restrict stock repurchases by Columbia Financial, Inc.

Applicable regulations restrict us from repurchasing our shares of common stock during the first year following the offering except to fund the grants of restricted stock under the stock-based incentive plan or unless extraordinary circumstances exist and may limit us from repurchasing our shares of common stock during the first three years following the offering. Stock repurchases are a capital management tool that can enhance the value of a company’s stock, and our inability to repurchase our shares of common stock during the first year following the offering and any limitations on our ability to repurchase our shares of common stock during the first three years following the offering may negatively affect our stock price.

You may not revoke your decision to purchase shares of Columbia Financial, Inc. common stock in the subscription or community offerings after you send us your order.

Funds submitted or withdrawals authorized in connection with the purchase of shares of common stock in the subscription and community offerings will be held by us until the completion or termination of the offering, including any extension of the expiration date. Because completion of the offering will be subject to regulatory approvals and an update of the independent appraisal prepared by RP Financial, among other factors, there may be one or more delays in completing the offering. Orders submitted in the subscription and community offerings are irrevocable, and purchasers will have no access to their funds unless the offering is terminated, significantly modified, or extended beyond July 31, 2026, or the number of shares to be sold in the offering is increased to more than 192,625,000 shares or decreased to fewer than 142,375,000 shares.

The distribution of subscription rights could have adverse income tax consequences.

If the subscription rights granted to certain current or former depositors and certain borrowers of Columbia Bank are deemed to have an ascertainable value, receipt of such rights may be taxable in an amount equal to such value. Whether

subscription rights are considered to have ascertainable value is an inherently factual determination. We have received a letter from RP Financial, our independent appraiser, which states its belief, without having undertaken any independent investigation of state or federal law or the position of the Internal Revenue Service, that as a factual matter the subscription rights will have no ascertainable market value; however, such letter is not binding on the Internal Revenue Service.

A WARNING ABOUT FORWARD-LOOKING STATEMENTS

This prospectus contains forward-looking statements, which can be identified by the use of words such as “believes,” “expects,” “anticipates,” “estimates” or similar expressions. Forward-looking statements include, but are not limited to:

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statements of our goals, intentions and expectations;

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statements regarding our business plans, prospects, growth and operating strategies;

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statements regarding the quality of our loan and securities portfolios; and

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estimates of our risks and future costs and benefits.

These forward-looking statements are subject to significant risks and uncertainties. Actual results may differ materially from those contemplated by the forward-looking statements due to, among other things, the following factors:

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failure to complete the conversion;

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failure to successfully integrate our business with that of Northfield Bancorp, or to integrate them in a timely manner;

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failure to achieve anticipated cost savings, or to achieve cost savings in a timely manner;

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costs, customer loss and business disruption in connection with the acquisition or the integration of our companies that may be greater than expected;

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failure to receive governmental approvals without adverse regulatory conditions;

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failure to obtain required stockholder and member approvals;

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general economic conditions, either nationally or in our market area, that are worse than expected, including recessionary conditions;

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changes in the interest rate environment that reduce our net interest margin, reduce the fair value of financial instruments or reduce the demand for our loan products;

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increased competitive pressures among financial services companies;

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changes in consumer spending, borrowing and savings habits;

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changes in the quality and composition of our loan or securities portfolios;

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changes in real estate market values in our market area;

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decreased demand for loan products, deposit flows, competition, or demand for financial services in our market area;

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major catastrophes such as earthquakes, floods or other natural or human disasters and pandemics and infectious disease outbreaks, the related disruption to local, regional and global economic activity and financial markets, and the impact that any of the foregoing may have on us and our customers and other constituencies;

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legislative or regulatory changes that adversely affect our business or changes in the monetary and fiscal policies of the U.S. government, including policies of the U.S. Treasury and the Federal Reserve Board;

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the effect of the imposition of tariffs and any retaliatory responses;

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the impact of any federal government shutdowns;

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the effect of war, terrorism, riots, civil insurrection or social unrest, or other events beyond our control;

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our ability to enter new markets successfully and capitalize on growth opportunities;

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our ability to grow our franchise through acquisitions and to successfully integrate any acquired entities;

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technological changes that may be more difficult or expensive than expected, and our inability to respond to emerging technological trends in a timely manner could have a negative impact on our revenue;

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success or consummation of new business initiatives may be more difficult or expensive than expected;

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adverse changes in the securities markets;

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cyber attacks, computer viruses and other technological risks that may breach the security of our systems and allow unauthorized access to confidential information;

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the inability of third party service providers to perform;

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the impact of legal, judicial and regulatory proceedings or investigations, and

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changes in accounting policies and practices, as may be adopted by bank regulatory agencies or the Financial Accounting Standards Board, the Public Company Accounting Oversight Board and the Securities and Exchange Commission.

Any of the forward-looking statements that we make in this prospectus and in other public statements we make may later prove incorrect because of inaccurate assumptions, the factors illustrated above or other factors that we cannot foresee. Consequently, no forward-looking statements can be guaranteed. Except as required by applicable law or regulation, we do not undertake, and we specifically disclaim any obligation, to release publicly the result of any revisions that may be made to any forward-looking statements to reflect events or circumstances after the date of the statements or to reflect the occurrence of anticipated or unanticipated events.

Further information on other factors that could affect us are included in the section captioned “Risk Factors.”

SELECTED CONSOLIDATED FINANCIAL AND OTHER DATA

OF COLUMBIA FINANCIAL AND SUBSIDIARIES

The summary financial information presented below is derived in part from Columbia Financial’s consolidated financial statements. The following is only a summary and you should read it in conjunction with the consolidated financial statements and notes beginning on page F-1. The information as of December 31, 2025 and 2024 and for the years ended December 31, 2025, 2024 and 2023 is derived in part from the audited consolidated financial statements that appear in this prospectus. The information at December 31, 2023, 2022 and 2021, and for the years ended December 31, 2022 and 2021, is derived in part from our audited financial statements that do not appear in this prospectus. The information presented below reflects Columbia Financial on a consolidated basis and does not include the financial condition, results of operations or other data of Columbia Bank MHC.


	At and For the Year Ended December 31,
	2025		2024			2023		2022		2021
	(Dollars in thousands, except share and per share data)
Financial Condition Data:
Total assets	$	11,018,793	$	10,475,493		$	10,645,568	$	10,408,169	$	9,224,097
Total and cash equivalents		340,806		289,223			423,249		179,228		70,963
Debt securities available-for-sale		1,122,017		1,025,946			1,093,557		1,328,634		1,703,847
Debt securities held-to-maturity		396,233		392,840			401,154		421,523		429,734
Equity securities		6,802		6,673			4,079		3,384		2,710
Loans receivable, net		8,224,809		7,856,970			7,819,441		7,624,761		6,297,912
Deposits		8,444,079		8,096,149			7,846,556		8,001,159		7,570,216
Federal Home Loan Bank advances		64,604		60,387			81,022		58,114		23,141
Stockholders’ equity		1,160,728		1,080,376			1,040,335		1,053,595		1,079,081

Operating Data:
Interest income		470,951		451,426			394,978		309,670		270,150
Interest expense		249,317		273,444			189,102		42,893		37,016
Net interest income		221,634		177,982			205,876		266,777		233,134
Provision for (reversal of) credit losses		9,822		14,451			4,787		5,485		(9,953	)
Net interest income after provision for (reversal of) credit losses		211,812		163,531			201,089		261,292		243,087
Non-interest income		37,069		1,894			27,379		30,400		38,831
Non-interest expense		180,982		181,335			182,417		174,816		155,737
Income (loss) before income tax expense (benefit)		67,989		(15,910	)		46,051		116,876		126,181
Income tax expense (benefit)		16,223		(4,257	)		9,965		30,703		34,132
Net income (loss)		51,766		(11,653	)		36,086		86,173		92,049
Weighted average common shares outstanding — basic		101,810,752		101,676,758			102,656,388		105,580,823		104,156,112
Weighted average common shares outstanding — diluted		101,810,752		101,839,507			102,894,969		106,193,161		104,156,112


	At and For the Year Ended December 31,
	2025			2024			2023			2022			2021
Performance Ratios:
Return on average assets		0.48	%		(0.11	)%		0.35	%		0.88	%		1.01	%
Return on average equity		4.63			(1.11	)		3.29			8.09			8.98
Interest rate spread⁽¹⁾		1.63			1.17			1.62			2.82			2.62
Net interest margin⁽²⁾		2.24			1.82			2.16			2.98			2.76
Non-interest expense to average assets		1.70			1.73			1.80			1.74			1.71
Efficiency ratio⁽³⁾		69.92			100.81			78.20			58.63			57.26
Average interest-earning assets/average interest-bearing liabilities		124.37			124.02			125.32			130.79			133.17
Average equity to average assets		10.37			9.88			10.59			10.93			11.26

Capital Ratios:⁽⁴⁾
Total capital (to risk-weighted assets)		14.09			14.41			14.02			14.12			15.39
Tier 1 capital (to risk-weighted assets)		13.20			13.56			13.22			13.32			14.38
Common equity Tier 1 capital (to risk-weighted assets)		13.20			13.56			13.22			13.32			14.38
Core (Tier 1) capital (to adjusted total assets)		9.67			9.64			9.48			9.74			9.80


	At and For the Year Ended December 31,
	2025			2024			2023			2022			2021
Asset Quality Ratios:
Allowance for loan losses as a percent of gross loans		0.82	%		0.76	%		0.70	%		0.69	%		0.99	%
Allowance for loan losses as a percent of non-performing loans		176.84			276.29			436.65			785.64			1,591.50
Net charge-offs to average outstanding loans during the period		0.07			0.07			0.01			—			0.03
Non-performing loans as a percent of gross loans⁽⁵⁾		0.46			0.28			0.16			0.09			0.06
Non-performing assets as a percent of total assets⁽⁵⁾		0.34			0.22			0.12			0.06			0.04
Other Data:
Number of offices		71			69			67			67			64

(1)	Represents the difference between the weighted average yield on average interest-earning assets and the weighted average cost of average interest-bearing liabilities.

(2)	Represents net interest income as a percent of average interest-earning assets.

(3)	Represents non-interest expense divided by the sum of net interest income and non-interest income.

(4)	Ratios are for Columbia Bank.

(5)	Non-performing loans include loans on non-accrual, accruing loans past due 90 days or more and non-performing assets include non-performing loans and other real estate owned.

SELECTED CONSOLIDATED FINANCIAL AND OTHER DATA

OF NORTHFIELD BANCORP AND SUBSIDIARIES

The summary financial information presented below is derived in part from Northfield Bancorp’s consolidated financial statements. The following is only a summary and you should read it in conjunction with the consolidated financial statements and notes beginning on page F-79. The information as of December 31, 2025 and 2024 and for the years ended December 31, 2025, 2024 and 2023 is derived in part from the audited consolidated financial statements of Northfield Bancorp that appear in this prospectus. The information at December 31, 2023, 2022 and 2021, and for the years ended December 31, 2022 and 2021, is derived in part from audited financial statements of Northfield Bancorp that do not appear in this prospectus.


	At December 31,
	2025			2024			2023			2022			2021
	(Dollars in thousands)
Selected Financial Condition Data:
Total assets	$	5,754,010		$	5,666,378		$	5,598,396		$	5,601,293		$	5,430,542
Cash and cash equivalents		163,951			167,744			229,506			45,799			91,068
Trading securities		15,215			13,884			12,549			10,751			13,461
Debt securities available-for-sale, at estimated fair value		1,412,419			1,100,817			795,464			952,173			1,208,237
Debt securities held-to-maturity, at amortized cost		8,339			9,303			9,866			10,760			5,283
Equity securities		5,000			14,261			10,629			10,443			5,342
Loans held-for-sale		—			4,897			—			—			—
Loans held-for-investment, net		3,856,773			4,022,224			4,203,654			4,243,693			3,806,617
Allowance for credit losses		(38,144	)		(35,183	)		(37,535	)		(42,617	)		(38,973	)

Net loans held-for-investment		3,818,629			3,987,041			4,166,119			4,201,076			3,767,644
Bank-owned life insurance		182,828			175,759			171,543			167,912			164,500
Federal Home Loan Bank of New York stock, at cost		46,568			35,894			39,667			30,382			22,336
Operating lease right-of-use assets		25,789			27,771			30,202			34,288			33,943
Goodwill		—			41,012			41,012			41,012			41,012
Total liabilities		5,063,951			4,961,682			4,898,951			4,899,903			4,690,659
Deposits		4,015,809			4,138,477			3,878,435			4,150,219			4,169,334
Borrowed funds		900,216			666,402			859,272			583,859			421,755
Subordinated debentures, net of issuance costs		61,665			61,442			61,219			60,996			—
Operating lease liabilities		29,643			32,209			35,205			39,790			39,851
Total stockholders’ equity		690,059			704,696			699,445			701,390			739,883


	Years Ended December 31,
	2025		2024		2023		2022		2021
	(Dollars in thousands, except share and per share data)
Selected Operating Data:
Interest income	$	249,096	$	237,908	$	208,795	$	179,688	$	172,298
Interest expense		111,730		123,423		84,128		21,382		16,649

Net interest income before provision for credit losses		137,366		114,485		124,667		158,306		155,649
Provision (benefit) for credit losses		7,402		4,281		1,353		4,482		(6,184	)

Net interest income after provision for credit losses		129,964		110,204		123,314		153,824		161,833
Non-interest income		16,950		16,822		11,896		7,983		14,453
Non-interest expense		129,863		86,525		83,450		76,948		79,159

Income before income taxes		17,051		40,501		51,760		84,859		97,127
Income tax expense		16,255		10,556		14,091		23,740		26,473

Net income	$	796	$	29,945	$	37,669	$	61,119	$	70,654

Net income per common share — basic	$	0.02	$	0.72	$	0.86	$	1.32	$	1.46
Net income per common share — diluted	$	0.02	$	0.72	$	0.86	$	1.32	$	1.45
Weighted average basic shares outstanding		40,116,839		41,567,370		43,560,844		46,234,122		48,416,495
Weighted average diluted shares outstanding		40,173,403		41,628,660		43,638,616		46,438,119		48,754,263


	At or For the Years Ended December 31,
	2025			2024			2023			2022			2021
Selected Financial Ratios and Other Data:
Performance Ratios:
Return on assets (ratio of net income to average total assets)^{(1)(2)(3)(4)(5)}		0.01	%		0.52	%		0.68	%		1.09	%		1.29	%
Return on equity (ratio of net income to average equity)^{(1)(2)(3)(4)(5)}		0.11			4.30			5.45			8.57			9.42
Interest rate spread⁽⁶⁾		1.92			1.45			1.82			2.82			2.89
Net interest margin⁽⁷⁾		2.55			2.10			2.35			2.97			3.01
Dividend payout ratio⁽⁸⁾		NM			72.89			60.51			39.48			34.39
Efficiency ratio^(9)(10)		84.15			65.90			61.11			46.27			46.54
Non-interest expense to average total assets		2.29			1.51			1.50			1.38			1.44
Average interest-earning assets to average interest-bearing liabilities		130.14			128.77			133.01			137.82			135.63
Average equity to average total assets		12.57			12.14			12.44			12.75			13.69
Asset Quality Ratios:
Non-performing assets to total assets		0.28			0.36			0.20			0.18			0.15
Non-performing loans to total loans^(11)(12)		0.42			0.51			0.27			0.24			0.21
Allowance for credit losses to total non-performing loans⁽¹³⁾		236.42			227.72			328.30			416.26			486.80
Allowance for credit losses to total loans held-for-investment, net⁽¹⁴⁾		0.99			0.87			0.89			1.00			1.02
Capital Ratio:
Tier 1 capital (to adjusted assets)		12.24			12.11			12.58			12.64			12.93
Other Data:
Number of full service offices		37			37			39			38			38
Full time equivalent employees		372			359			401			400			385

(1)	The year ended December 31, 2025, included a $41.0 million non-cash, non-tax deductible goodwill impairment charge and $580,000 additional tax expense related to options that expired in May 2025.

(2)	The year ended December 31, 2024, included a $2.4 million, after tax, gain on the sale of property, $795,000 additional tax expense related to options that expired in June 2024, and $492,000, after tax, of severance costs.

(3)	The year ended December 31, 2023, included $317,000, after tax, of severance costs and $96,000, after tax, of gains on loans sold.

(4)	The year ended December 31, 2022, included $925,000, after tax, of net interest income generated from accelerated accretion of fees related to the forgiveness of PPP loans and $326,000, after-tax, in gains on loans sold.

(5)

The year ended December 31, 2021, included: (i) $4.0 million, after tax, of net interest income generated from accelerated accretion of fees related to the forgiveness of PPP loans; (ii) $1.4 million, after tax, of accretable income related to the payoff of PCD loans; (iii) $1.0 million, after tax, in gains on loans sold; and (iv) $677,000 of tax-exempt income from bank-owned life insurance proceeds in excess of the cash surrender value of the policies.

(6)	The interest rate spread represents the difference between the weighted-average yield on interest-earning assets and the weighted-average costs of interest-bearing liabilities.

(7)	The net interest margin represents net interest income as a percent of average interest-earning assets for the period.

(8)	Dividend payout ratio is calculated as total dividends declared for the year divided by net income for the year.

(9)	The efficiency ratio represents non-interest expense divided by the sum of net interest income and non-interest income.

(10)

The year ended December 31, 2025, included a $41.0 million non-cash, non-tax deductible goodwill impairment charge. The year ended December 31, 2024, included a $3.4 million, pre-tax, gain on the sale of property, and $683,000, pre-tax, of severance expense. The year ended December 31, 2023, includes $440,000, pre-tax, of severance expense.

(11)	Non-performing loans consist of non-accruing loans and loans 90 days or more past due and still accruing (excluding PCD loans), included in total loans held-for-investment, net, and non-performing loans held-for-sale, included in loans held-for-sale.

(12)	Includes originated loans held-for-investment, PCD loans, acquired loans, and loans held-for-sale.

(13)	Excludes non-performing loans held-for-sale.

(14)	Includes originated loans held-for-investment, PCD loans and acquired loans (and related allowance for credit losses).

RECENT DEVELOPMENTS OF COLUMBIA FINANCIAL

The summary financial information presented below is derived in part from Columbia Financial’s consolidated financial statements. The following is only a summary and you should read it in conjunction with the consolidated financial statements and notes beginning on page F-1. The information as of December 31, 2025 is derived in part from the audited consolidated financial statements that appear in this prospectus. The financial condition data at March 31, 2026 and the operating data for the three months ended March 31, 2026 and 2025 are not audited but, in the opinion of management, reflects all adjustments necessary for a fair presentation. All such adjustments are normal and recurring and are the only adjustments reflected in the financial data presented below. The information presented below reflects Columbia Financial on a consolidated basis and does not include the financial condition, results of operations or other data of Columbia Bank MHC. KPMG LLP has not audited or reviewed the following financial condition and operating data. Accordingly, KPMG LLP does not express an opinion or any other form of assurance with respect thereto.


	At March 31, 2026		At December 31, 2025
	(Unaudited)
	(In thousands)
Selected Financial Condition Data:

Total assets	$	11,010,507	$	11,018,793
Cash and cash equivalents		276,947		340,806
Debt securities available for sale		1,198,870		1,122,017
Debt securities held to maturity		377,847		396,233
Loans receivable, net		8,190,917		8,224,809
Deposits		8,372,014		8,444,079
Borrowings		1,243,462		1,183,472
Stockholders’ equity		1,173,722		1,160,728


	For the Three Months Ended March 31,
	2026		2025
	(Unaudited)
	(In thousands)
Selected Operating Data:
Interest income	$	118,871	$	112,163
Interest expense		58,480		61,838
Net interest income		60,391		50,325
Provision for credit losses		956		2,933
Net interest income after provision for credit losses		59,435		47,392
Non-interest income		6,747		8,471
Non-interest expense		47,487		43,845
Income before income tax expense		18,695		12,018
Income tax expense		5,596		3,118
Net income		13,099		8,900

Weighted average shares outstanding — basic		101,266,942		101,816,716
Weighted average shares outstanding — diluted		101,453,090		101,816,716


	At or For the Three Months Ended March 31,
	2026			2025
	(Unaudited)
Performance Ratios:
Return on average assets		0.48	%		0.34	%
Return on average equity		4.55			3.31
Interest rate spread⁽¹⁾		1.84			1.48
Net interest margin⁽²⁾		2.42			2.11
Non-interest expense to average assets		1.75			1.68
Efficiency ratio⁽³⁾		70.73			74.57
Average interest-earning assets to average interest-bearing liabilities		124.59			123.96
Average equity to average assets		10.58			10.33


	At or For the Three Months Ended March 31,
	2026			2025
	(Unaudited)
Capital Ratios:⁽⁴⁾
Total capital (to risk-weighted assets)		15.14			14.12
Tier 1 capital (to risk-weighted assets)		14.23			13.30
Common equity Tier 1 capital (to risk-weighted assets)		14.14			13.21
Core (Tier 1) capital (to adjusted total assets)		10.40			10.29

Asset Quality Ratios:
Allowance for loan losses as a percent of gross loans		0.84	%		0.78	%
Allowance for loan losses as a percent of non-performing loans		166.19			249.57
Net (recoveries) charge-offs to average outstanding loans during the period		(0.03	)		0.04
Non-performing loans as a percent of total gross loans⁽⁵⁾		0.50			0.31
Non-performing assets as a percent of total assets⁽⁵⁾		0.43			0.25
Other Data:
Number of offices		70			69
Number of full-time equivalent employees		785			738

(1)	Represents the difference between the weighted average yield on average interest-earning assets and the weighted average cost of average interest-bearing liabilities.

(2)	Represents net interest income as a percent of average interest-earning assets.

(3)	Represents non-interest expense divided by the sum of net interest income and non-interest income.

(4)	Ratios are for Columbia Bank.

(5)	Non-performing loans include loans on non-accrual, accruing loans past due 90 days or more. Non-performing assets include non-performing loans and other real estate owned.

Comparison of Financial Condition at March 31, 2026 and December 31, 2025

Total assets decreased $8.3 million, or 0.1%, with a balance of $11.0 billion at both March 31, 2026 and December 31, 2025. The decrease in total assets was primarily attributable to decreases in cash and cash equivalents of $63.9 million, debt securities held to maturity of $18.4 million, and loans receivable, net, of $33.9 million, partially offset by an increase in debt securities available for sale of $76.9 million, an increase in Federal Home Loan Bank and Federal Reserve Bank stock of $18.3 million and an increase in other real estate owned of $5.9 million, representing one non-performing construction loan transferred to other real estate owned in March 2026.

Cash and cash equivalents decreased $63.9 million, or 18.7%, to $276.9 million at March 31, 2026 from $340.8 million at December 31, 2025. The decrease was primarily attributable to purchases of securities of $138.2 million, the purchase of Federal Reserve Bank of New York Stock, the origination of loans receivable, and a decrease in total deposits of $72.1 million, partially offset by principal repayments on securities of $20.9 million, calls and maturities on securities of $54.9 million, repayments on loans receivable and an increase in borrowings of $60.0 million.

Debt securities available for sale increased $76.9 million, or 6.8%, to $1.2 billion at March 31, 2026 from $1.1 billion at December 31, 2025. The increase was attributable to purchases of securities of $138.2 million, consisting primarily of U.S. government obligations and mortgage-backed securities, partially offset by an increase in the gross unrealized loss on securities of $4.8 million, calls and maturities on securities of $40.0 million, and repayments on securities of $17.1 million.

Debt securities held to maturity decreased $18.4 million, or 4.6%, to $377.8 million at March 31, 2026 from $396.2 million at December 31, 2025. The decrease was primarily attributable to maturities on securities of $14.9 million and repayments on securities of $3.8 million.

Loans receivable, net, decreased $33.9 million, or 0.4%, with a balance of $8.2 billion at both March 31, 2026 and December 31, 2025. One-to-four family loans, multifamily loans, commercial real estate loans, commercial business loans, and home equity loans and advances decreased $14.7 million, $8.4 million, $40.3 million, $14.5 million, and $5.6 million, respectively, partially offset by an increase in construction loans of $51.3 million. The allowance for credit losses for loans increased $1.6 million to $68.8 million at March 31, 2026 from $67.2 million at December 31, 2025, primarily due to an increase in qualitative loss rates based on the evaluation of current and projected economic conditions.

Total liabilities decreased $21.3 million, or 0.2%, to $9.8 billion at March 31, 2026 from $9.9 billion at December 31, 2025. The decrease was primarily attributable to a decrease in total deposits of $72.1 million, or 0.9%, and a decrease in

accrued expenses and other liabilities of $11.3 million, partially offset by an increase in borrowings of $60.0 million, or 5.1%. The decrease in total deposits primarily consisted of decreases in non-interest-bearing demand deposits, interest-bearing demand deposits and money market accounts of $9.4 million, $102.9 million, and $13.8 million, respectively, partially offset by increases in savings and club accounts and certificates of deposits of $1.6 million and $52.4 million, respectively. The decrease in accrued expenses and other liabilities related to the payout of benefit related accrued expenses coupled with a decrease in outstanding checks. The $60.0 million increase in borrowings was driven by a net increase in short-term borrowings of $35.0 million, coupled with new long-term borrowings of $40.0 million, partially offset by repayments of $15.0 million in maturing long-term borrowings.

Total stockholders’ equity increased $13.0 million, or 1.1%, with a balance of $1.2 billion at both March 31, 2026 and December 31, 2025, primarily attributable to net income of $13.1 million.

Comparison of Operating Results for the Three Months Ended March 31, 2026 and March 31, 2025

General. Net income of $13.1 million was recorded for the quarter ended March 31, 2026, an increase of $4.2 million, compared to net income of $8.9 million for the quarter ended March 31, 2025. The increase in net income was primarily attributable to a $10.1 million increase in net interest income, and a $2.0 million decrease in provision for credit losses, partially offset by a $1.7 million decrease in non-interest income, a $3.6 million increase in non-interest expense, and a $2.5 million increase in income tax expense.

Interest Income. Total interest income was $118.9 million for the quarter ended March 31, 2026, an increase of $6.7 million, or 5.98%, from $112.1 million for the quarter ended March 31, 2025. The increase in interest income was primarily due to an increase in the average balance of loans and securities coupled with an increase in average yields on loans. The average yield on loans for the quarter ended March 31, 2026 increased 12 basis points to 5.01%, as compared to 4.89% for the quarter ended March 31, 2025. The average yield on securities for the quarter ended March 31, 2026 decreased 7 basis points to 3.38%, as compared to 3.45% for the quarter ended March 31, 2025. Interest income on securities increased due to an increase in the average balance of securities which more than offset a decrease in the average yield. The average yield on other interest-earning assets for the quarter ended March 31, 2026 decreased 97 basis points to 4.78%, as compared to 5.75% for the quarter ended March 31, 2025, mainly due to a 165 basis point decrease in the dividend rate received on Federal Home Loan Bank stock.

Interest Expense. Total interest expense was $58.5 million for the quarter ended March 31, 2026, a decrease of $3.4 million, or 5.4%, from $61.8 million for the quarter ended March 31, 2025. The decrease in interest expense was primarily attributable to a 30 basis point decrease in the average cost of interest-bearing deposits coupled with a 32 basis point decrease in the average cost of borrowings, partially offset by an increase in both the average balance of interest-bearing deposits and borrowings. Interest expense on deposits decreased $3.8 million, or 7.6% due to the decrease in the average cost of deposits. Interest expense on borrowings increased $476,000, or 4.1%, for the quarter ended March 31, 2026 as compared to the quarter ended March 31, 2025, due to the increase in the average balance of borrowings, which more than offset the decrease in the average cost.

Provision for Credit Losses. The provision for credit losses for the quarter ended March 31, 2026 was $1.0 million, a decrease of $2.0 million, or 67.4%, from $2.9 million for the quarter ended March 31, 2025. The decrease in provision for credit losses was primarily attributable to a decrease in net charge-offs, with net recoveries on loans of $604,000 for the quarter ended March 31, 2026, as compared to net charge-offs on loans of $857,000 for the quarter ended March 31, 2025, and a decrease in the balance of loans receivable.

Non-Interest Income. Non-interest income was $6.7 million for the quarter ended March 31, 2026, a decrease of $1.7 million, or 20.4%, from $8.5 million for the quarter ended March 31, 2025. The decrease was primarily attributable to a decrease in the change in fair value of equity securities of $1.5 million, and a decrease of $379,000 in other non-interest income, mainly related to interest rate swaps.

Non-Interest Expense. Non-interest expense was $47.5 million for the quarter ended March 31, 2026, an increase of $3.6 million, or 8.3%, from $43.8 million for the quarter ended March 31, 2025. The increase was primarily attributable to an increase in compensation and employee benefits expense of $2.5 million, and an increase in merger-related expenses of $1.8 million, partially offset by a decrease of $1.1 million in professional fees. The increase in compensation and employee benefits expense was due to normal annual increases and an increase in the number of employees.

Income Tax Expense. Income tax expense was $5.6 million for the quarter ended March 31, 2026, an increase of $2.5 million, as compared to income tax expense of $3.1 million for the quarter ended March 31, 2025, mainly due to higher pre-tax income. Columbia Financial’s effective tax rate was 29.9% and 25.9% for the quarters ended March 31, 2026 and 2025, respectively. The increase in the 2026 effective tax rate was due to the 2026 period including non-deductible merger-related expenses.

Asset Quality

Columbia Financial’s non-performing loans at March 31, 2026 totaled $41.4 million, or 0.50% of total gross loans, as compared to $38.0 million, or 0.46% of total gross loans, at December 31, 2025. The $3.4 million increase in non-performing loans was primarily attributable to one $10.6 million commercial real estate loan on a six-story mixed use building which includes apartments and commercial/storage space designated as non-performing during the 2026 period, partially offset by a decrease in non-performing commercial business loans of $1.6 million, and a decrease in non-performing construction loans of $5.9 million. The decrease in non-performing construction loans was due to one loan secured by a mixed use five-story building with both commercial space and apartments, being transferred to other real estate owned in March 2026.


	At March 31, 2026		At December 31, 2025
	(In thousands)
Non-accrual loans:
One-to-four family	$	9,330	$	9,787
Multifamily		—		—
Commercial real estate		16,962		5,766
Construction		—		5,923
Commercial business loans		14,250		15,281
Home Equity loans and advances		833		1,243

Total non-accrual loans	$	41,375	$	38,000

RECENT DEVELOPMENTS OF NORTHFIELD BANCORP

The summary financial information presented below is derived in part from Northfield Bancorp’s consolidated financial statements. The following is only a summary and you should read it in conjunction with the consolidated financial statements and notes beginning on page F-79. The financial condition data at December 31, 2025 are derived from the audited consolidated financial statements of Northfield Bancorp included elsewhere in this prospectus. The financial condition data at March 31, 2026 and the operating data for the three months ended March 31, 2026 and 2025 are not audited but, in the opinion of management, reflects all adjustments necessary for a fair presentation. All such adjustments are normal and recurring and are the only adjustments reflected in the financial data presented below. Crowe LLP has not audited or reviewed the following financial condition and operating data. Accordingly, Crowe LLP does not express an opinion or any other form of assurance with respect thereto.


	At March 31, 2026			At December 31, 2025
	(Unaudited)
	(Dollars in thousands)
Selected Financial Condition Data:
Total assets	$	5,735,202		$	5,754,010
Cash and cash equivalents		239,607			163,951
Trading securities		13,831			15,215
Debt securities available-for-sale, at estimated fair value		1,378,502			1,412,419
Debt securities held-to-maturity, at amortized cost		8,278			8,339
Equity securities		5,000			5,000
Loans held-for-investment, net		3,807,957			3,856,773
Allowance for credit losses		(37,034	)		(38,144	)

Net loans held-for-investment		3,770,923			3,818,629
Bank-owned life insurance		184,718			182,828
Federal Home Loan Bank of New York stock, at cost		42,195			46,568
Operating lease right-of-use assets		24,588			25,789
Total liabilities		5,040,512			5,063,951
Deposits		4,088,617			4,015,809
Borrowed funds		802,185			900,216
Subordinated debentures, net of issuance costs		61,721			61,665
Operating lease liabilities		28,348			29,643
Total stockholders’ equity		694,690			690,059


	For the Three Months Ended March 31,
	2026		2025
	(Unaudited)
	(Dollars in thousands, except share and per share data)
Selected Operating Data:
Interest income	$	62,908	$	60,092
Interest expense		25,945		28,301

Net interest income before provision for credit losses		36,963		31,791
Provision for credit losses		247		2,582

Net interest income after provision for credit losses		36,716		29,209
Non-interest income		3,412		3,022
Non-interest expense		23,259		21,435

Income before income taxes		16,869		10,796
Income tax expense		5,026		2,920
Net income	$	11,843	$	7,876

Net income per common share — basic	$	0.30	$	0.19
Net income per common share — diluted	$	0.30	$	0.19
Weighted average basis shares outstanding		39,785,507		40,864,529
Weighted average diluted shares outstanding		39,922,591		40,922,829


	At or For the Three Months Ended March 31,
	2026			2025
	(Unaudited)
Selected Financial Ratios and Other Data:
Performance Ratios:
Return on assets (ratio of net income to average total assets)⁽¹⁾		0.85	%		0.56	%
Return on equity (ratio of net income to average equity)⁽¹⁾		6.93			4.52
Interest rate spread⁽²⁾		2.17			1.76
Net interest margin⁽¹⁾⁽³⁾		2.76			2.38
Dividend payout ratio⁽⁴⁾		44.59			68.40
Efficiency ratio⁽⁵⁾		57.61			61.57
Non-interest expense to average total assets⁽¹⁾		1.66			1.53
Average interest-earning assets to average interest-bearing liabilities		130.15			129.42
Average equity to average total assets		12.20			12.43
Asset Quality Ratios:
Non-performing assets to total assets		0.37			0.34
Non-performing loans to total loans⁽⁶⁾⁽⁷⁾		0.56			0.48
Allowance for credit losses to total non-performing loans⁽⁸⁾		172.93			242.73
Allowance for credit losses to total loans held-for-investment, net⁽⁹⁾		0.97			0.87
Capital Ratio:
Northfield Bank Community Bank Leverage Ratio (CBLR)		13.08			12.62
Northfield Bancorp CBLR		12.34			12.08

Other Data:
Number of full service offices		37			37
Full-time equivalent employees		369			371

(1)	Annualized

(2)	The interest rate spread represents the difference between the weighted-average yield on interest-earning assets and the weighted-average costs of interest-bearing liabilities.

(3)	The net interest margin represents net interest income as a percent of average interest-earning assets for the period.

(4)	Dividend payout ratio is calculated as total dividends declared for the year divided by net income for the period.

(5)	The efficiency ratio represents non-interest expense divided by the sum of net interest income and non-interest income.

(6)	Non-performing loans consist of non-accruing loans and loans 90 days or more past due and still accruing (excluding PCD loans), included in total loans held-for-investment, net, and non-performing loans held-for-sale, included in loans held-for-sale.

(7)	Includes originated loans held-for-investment, PCD loans, acquired loans, and loans held-for-sale.

(8)	Excludes non-performing loans held-for-sale.

(9)	Includes originated loans held-for-investment, PCD loans and acquired loans (and related allowance for credit losses).

Comparison of Financial Condition at March 31, 2026 and December 31, 2025

Total assets decreased by $18.8 million, or 0.3%, to $5.74 billion at March 31, 2026, from $5.75 billion at December 31, 2025. The decrease was primarily due to decreases in loans held-for-investment, net, of $48.8 million, or 1.3%, available-for-sale debt securities of $33.9 million, or 2.4%, other assets of $7.1 million, or 20.2%, and Federal Home Loan Bank of New York stock of $4.4 million, or 9.4%, partially offset by an increase in cash and cash equivalents of $75.7 million, or 46.1%.

Cash and cash equivalents increased by $75.7 million, or 46.1%, to $239.6 million at March 31, 2026, from $164.0 million at December 31, 2025. Balances fluctuate based on the timing of receipt of security and loan repayments and the redeployment of cash into higher-yielding assets such as loans and securities, or the funding of deposit outflows or borrowing maturities.

Loans held-for-investment, net, decreased by $48.8 million, or 1.3%, to $3.81 billion at March 31, 2026 from $3.86 billion at December 31, 2025, primarily due to a decrease in multifamily real estate loans. The decrease in multifamily loan balances reflects our continued strategic focus on managing concentration risk within our commercial and multifamily real estate loan portfolios, while maintaining disciplined loan pricing. Multifamily loans decreased $47.3 million, or 2.0%, to $2.31 billion at March 31, 2026 from $2.36 billion at December 31, 2025. Commercial real estate loans decreased $9.8 million, or 1.1%, to $901.6 million at March 31, 2026 from $911.4 million at December 31, 2025. Home equity and lines of credit decreased $2.9 million, or 1.4%, to $195.7 million at March 31, 2026 from $198.6 million at December 31,

2025. One-to-four family residential loans decreased $901,000, or 0.5%, to $164.2 million at March 31, 2026 from $165.1 million at December 31, 2025. Partially offsetting these decreases were increases in commercial and industrial loans of $6.8 million, or 4.1%, to $173.0 million at March 31, 2026 from $166.2 million at December 31, 2025, as a result of an increase in originations related to new lenders. Construction and land loans increased $5.6 million, or 12.7%, to $50.2 million at March 31, 2026 from $44.5 million at December 31, 2025, primarily attributable to advances on existing loans.

Our available-for-sale debt securities portfolio decreased by $33.9 million, or 2.4%, to $1.38 billion at March 31, 2026, from $1.41 billion at December 31, 2025. The decrease was primarily attributable to paydowns and maturities. At March 31, 2026, $1.33 billion of the portfolio consisted of residential mortgage-backed securities issued or guaranteed by Fannie Mae, Freddie Mac, or Ginnie Mae. In addition, we held $47.8 million in corporate bonds, substantially all of which were investment grade, $614,000 in municipal bonds and $540,000 in U.S. Government agency securities at March 31, 2026. Unrealized losses, net of tax, on available-for-sale debt securities and held-to-maturity securities approximated $10.8 million and $244,000, respectively, at March 31, 2026, and $10.5 million and $206,000, respectively, at December 31, 2025.

Equity securities were $5.0 million at both March 31, 2026 and December 31, 2025, respectively. Equity securities are comprised of an investment in a Small Business Administration Loan Fund. This investment is utilized by Northfield Bank as part of its Community Reinvestment Act program.

Other assets decreased by $7.1 million, or 20.2%, to $28.1 million at March 31, 2026, from $35.2 million at December 31, 2025. The decrease was primarily attributable to a decrease in tax assets (deferred and receivables) and proceeds due from broker.

Total liabilities decreased $23.4 million, or 0.5%, to $5.04 billion at March 31, 2026, from $5.06 billion at December 31, 2025. The decrease was primarily attributable to a decrease in borrowings of $98.0 million, partially offset by an increase in deposits of $72.8 million. We routinely utilize brokered deposits and borrowed funds to manage interest rate risk, the cost of interest-bearing liabilities, and funding needs related to loan originations and deposit activity.

Deposits, excluding brokered deposits, increased $83.3 million, or 2.1%, to $4.06 billion at March 31, 2026 as compared to $3.98 billion at December 31, 2025. The increase in deposits, excluding brokered deposits, was primarily attributable to an increase of $99.8 million in transaction accounts and $13.7 million in savings accounts, partially offset by decreases of $20.1 million in time deposits, and $10.1 million in money market accounts. Growth in transaction and savings accounts was primarily the result of our focus on growing low/no cost checking deposits. We do not to compete with high rate time deposits offered by competitors, which accounted for the decrease in that product category.

Borrowed funds decreased to $863.9 million at March 31, 2026, from $961.9 million at December 31, 2025. The decrease in borrowings was primarily due to a $40.0 million decrease in borrowings under an overnight line of credit, and a $58.0 million decrease in other borrowings. We were able to reduce our reliance on borrowings due to an increase in deposits. Management utilizes borrowings to mitigate interest rate risk, for short-term liquidity, and to a lesser extent from time to time, as part of leverage strategies.

Total stockholders’ equity increased by $4.6 million to $694.7 million at March 31, 2026, from $690.1 million at December 31, 2025. The increase was attributable to net income of $11.8 million for the three months ended March 31, 2026, and a $500,000 increase in equity award activity, partially offset by $5.3 million in dividend payments, and a $2.4 million increase in accumulated other comprehensive loss associated with a decrease in the estimated fair value of our debt securities available-for-sale portfolio.

Comparison of Operating Results for the Three Months Ended March 31, 2026 and March 31, 2025

General. Net income was $11.8 million and $7.9 million for the three months ended March 31, 2026 and March 31, 2025, respectively. Significant variances from the comparable prior year period are as follows: a $5.2 million increase in net interest income, a $2.3 million decrease in the provision for credit losses on loans, a $390,000 increase in non-interest income, a $1.8 million increase in non-interest expense, and a $2.1 million increase in income tax expense.

Net Interest Income. Net interest income for the three months ended March 31, 2026, increased $5.2 million, or 16.3%, to $37.0 million, from $31.8 million for the three months ended March 31, 2025, due to a $2.8 million increase in interest income and a $2.4 million decrease in interest expense. The increase in interest income was primarily due to a 19 basis point increase in the yield on interest-earning assets, which increased to 4.69% for the three months ended March 31, 2026, from 4.50% for the three months ended March 31, 2025, due to higher yields on loans and mortgage-backed securities, and a $27.1 million, or 0.5%, increase in the average balance of interest-earning assets. The increase in the average balance of

interest-earning assets was primarily due to increases in the average balance of mortgage-backed securities of $218.6 million and the average balance of interest-earning deposits in financial institutions of $52.4 million, partially offset by decreases in the average balance of loans of $180.4 million and the average balance of other securities of $67.4 million. The decrease in interest expense was primarily due to a decrease in the cost of interest-bearing liabilities, which decreased by 22 basis points to 2.52% for the three months ended March 31, 2026, from 2.74% for the three months ended March 31, 2025, and a decrease in the average balance of interest-bearing liabilities of $2.4 million, or 0.1%. The decrease in the cost of interest-bearing liabilities was driven primarily by a 34 basis point decrease in the cost of interest-bearing deposits to 2.17% from 2.51%, attributable to a shift to lower cost deposit sources such as negotiable orders of withdrawal and savings accounts, partially offset by an 11 basis point increase in the cost of borrowed funds to 3.78% from 3.67%, attributable to increased utilization of short-term Federal Home Loan Bank advances. The average balance of interest-bearing liabilities decreased primarily due to an $84.5 million, or 2.5%, decrease in the average balance of interest-bearing deposits, primarily in certificates of deposit, partially offset by an $82.0 million, or 11.8%, increase in the average balance of borrowed funds.

Net interest margin increased by 38 basis points to 2.76% for the three months ended March 31, 2026, from 2.38% for the three months ended March 31, 2025. The increase in net interest margin was primarily due to higher yields on loans and mortgage-backed securities, coupled with a decrease in the cost of interest-bearing liabilities. We accreted interest income related to purchased credit-deteriorated (“PCD”) loans of $224,000 for the three months ended March 31, 2026, as compared to $223,000 for the three months ended March 31, 2025. Net interest income for the three months ended March 31, 2026, also included loan prepayment income of $74,000 as compared to $245,000 for the three months ended March 31, 2025.

Provision for Credit Losses. The provision for credit losses on loans decreased by $2.3 million to $247,000 for the three months ended March 31, 2026, compared to $2.6 million for the three months ended March 31, 2025, primarily due to a decrease in general reserves, partially offset by an increase in specific reserves. The decrease in general reserves was related to a decline in loan balances and lower net charge-offs, partially offset by an increase in qualitative reserves in our multifamily portfolio. The increase in specific reserves was related to one collateral-dependent commercial real estate loan. Net charge-offs were $1.4 million for the three months ended March 31, 2026, as compared to $2.8 million for the three months ended March 31, 2025, and included charge-offs of $1.3 million and $2.4 million on small business unsecured commercial and industrial loans for the three months ended March 31, 2026 and 2025, respectively. Management continues to closely monitor the small business unsecured commercial and industrial loan portfolio, which totaled $17.6 million at March 31, 2026.

Non-interest Income. Non-interest income increased by $390,000, or 12.9%, to $3.4 million for the three months ended March 31, 2026, compared to $3.0 million for the three months ended March 31, 2025. The increase was primarily due to an increase in income on bank-owned life insurance of $252,000 and an $89,000 increase in fees and service charges for customer services.

Non-interest Expense. Non-interest expense increased by $1.8 million, or 8.5%, to $23.3 million for the three months ended March 31, 2026, compared to $21.4 million for the three months ended March 31, 2025. The increase was primarily due to a $1.7 million increase in merger expenses related to the pending merger with Columbia Financial, Inc., and an $898,000 increase in employee compensation and benefits, primarily due to higher salary expense related to annual merit increases. Partially offsetting the increases were a $381,000 decrease in professional fees, primarily attributable to lower outsourced consulting and recruitment fees, a $170,000 decrease in credit loss expense/(benefit) for off-balance sheet exposure, and a $143,000 decrease in other non-interest expense. The decrease in credit loss expense/(benefit) for off-balance sheet exposure was due to a benefit of $67,000 recorded during the three months ended March 31, 2026, as compared to a provision of $103,000 recorded during the three months ended March 31, 2025, due to a decrease in the pipeline of loans committed and awaiting closing.

Income Tax Expense. We recorded income tax expense of $5.0 million for the three months ended March 31, 2026, compared to $2.9 million for the three months ended March 31, 2025. The effective tax rate for the three months ended March 31, 2026, was 29.8% compared to 27.0% for the three months ended March 31, 2025.

Asset Quality. Non-performing loans at March 31, 2026 totaled $21.4 million, or 0.56% of total loans, as compared to $16.1 million, or 0.42% of total loans, at December 31, 2025. The increase was primarily due to an increase in non-accrual commercial mortgage loans, primarily due to one loan with an outstanding balance of $6.5 million that was placed on non-accrual as it was 90 days past due at March 31, 2026. As of March 31, 2026, the loan is considered well secured by collateral property in New York with an appraised value of $13.1 million and is in the process of collection.


	At March 31,		At December 31,
	2026		2025
	(In thousands)
Non-accrual loans:
Held-for-investment
Real estate loans:
Multifamily	$	3,230	$	3,688
Commercial mortgage		11,485		5,012
Home equity and lines of credit		1,752		1,778
Commercial and industrial		4,494		4,732

Total non-accrual loans	$	20,961	$	15,210

HOW WE INTEND TO USE THE PROCEEDS OF THE OFFERING

Although we cannot determine what the actual net proceeds from the sale of the shares of common stock in the offering will be until the offering is completed, we anticipate that the net proceeds will be between $966.0 million and $1.9 billion. See the section of this prospectus entitled “Pro Forma Data” for the assumptions used to arrive at these amounts.

We intend to distribute the net proceeds as follows:


	Adjusted Minimum of Offering Range						Minimum of Offering Range						Midpoint of Offering Range						Maximum of Offering Range
	142,375,000 Shares at $10.00 Per Share			Percent of Net Proceeds			142,375,000 Shares at $10.00 Per Share			Percent of Net Proceeds			167,500,000 Shares at $10.00 Per Share			Percent of Net Proceeds			192,625,000 Shares at $10.00 Per Share			Percent of Net Proceeds
Gross offering proceeds	$	1,423,750					$	1,423,750					$	1,675,000					$	1,926,250
Less: offering expenses		(39,779	)					(36,311	)					(38,623	)					(43,070	)
Net offering proceeds		1,383,971						1,387,439						1,636,377						1,883,180
Merger shares used to complete offering (1)		(418,001	)					—						—						—

Net cash proceeds		965,970			100.00	%		1,387,439			100.00	%		1,636,377			100.00	%		1,883,180			100.00	%
Less:
Proceeds contributed to Columbia Bank		(482,985	)		50.00	%		(693,720	)		50.00	%		(818,189	)		50.00	%		(941,590	)		50.00	%
Proceeds used for loan to employee stock ownership plan		(42,713	)		4.42	%		(42,713	)		3.08	%		(50,250	)		3.07	%		(57,788	)		3.07	%
Cash merger consideration (2)		(179,143	)		18.55	%		(179,143	)		12.91	%		(179,143	)		10.95	%		(184,172	)		9.78	%

Proceeds remaining for Columbia Financial, Inc.	$	261,128			27.03	%	$	471,863			34.01	%	$	588,795			35.98	%	$	699,630			37.15	%

(1)

The number of shares of Columbia Financial, Inc. sold for cash at the adjusted minimum the offering will vary depending on the amount of the merger consideration that is paid in shares of Columbia Financial, Inc. This column assumes that 70% of the merger consideration will be shares of Columbia Financial, Inc., which would result in 100,574,860 shares that would need to be sold in the offering to satisfy the minimum offering requirement. If instead, 100% of the merger consideration is paid in shares of Columbia Financial, Inc., the number of shares required to be sold for cash to satisfy the minimum offering requirement would decrease at the adjusted minimum from 100,574,860 shares to 82,660,515 shares and the resulting net cash proceeds would be less than the amount shown in the table above. See “The Conversion and Offering — Shares Outstanding at Completion of Offering.”

(2)

Payments for shares of common stock made through withdrawals from existing deposit accounts will not result in the receipt of new funds for investment but will result in a reduction of Columbia Bank’s deposits. The net proceeds may vary because total expenses relating to the offering may be more or less than our estimates. For example, our expenses would increase if more than 30% of the shares are sold in a firm commitment underwritten offering.

We initially intend to invest the proceeds retained from the offering at Columbia Financial, Inc. after financing the cash portion of the merger consideration to acquire Northfield Bancorp in short-term investments, such as U.S. treasury and government agency securities, government agency mortgage-backed securities and cash and cash equivalents. The actual amounts to be invested in different instruments will depend on the interest rate environment and Columbia Financial, Inc.’s liquidity requirements. In the future, Columbia Financial, Inc. may liquidate its investments and use those funds:

•

to pay dividends to stockholders;

•

to repurchase shares of its common stock, subject to regulatory restrictions;

•

to finance the possible acquisition of financial institutions or other businesses that are related to banking as opportunities arise, primarily in or adjacent to our existing market areas, although we do not currently have any agreements or understandings regarding any specific acquisition transaction other than our pending merger with Northfield Bancorp; and

•

for other general corporate purposes, including to support our business strategies and contributing additional capital to Columbia Bank.

See “Our Dividend Policy” for a discussion of our expected dividend policy following the completion of the conversion. Under current federal regulations, we are not permitted to repurchase shares of our common stock during the first year following the completion of the conversion, except when extraordinary circumstances exist and with prior regulatory approval, or except to fund the granting of restricted stock awards (which would require notification to the Federal Reserve Board) or tax-qualified employee stock benefit plans.

Columbia Bank may use the net proceeds it receives from the offering:

•

to fund new loans;

•

to enhance existing products and services and to support growth;

•

to invest in investment-grade securities;

•

for the possible future expansion of our branch office network by establishing or acquiring additional branch offices;

•

for the possible acquisition of fee-based businesses; and

•

for other general corporate purposes.

We may need regulatory approvals to engage in some of the activities listed above.

We have not determined specific amounts of the net proceeds that would be used for the purposes described above. The use of the proceeds outlined above may change based on many factors, including, but not limited to, changes in interest rates, equity markets, laws and regulations affecting the financial services industry, the attractiveness and availability of potential acquisitions to expand our operations, and overall market conditions. The use of the proceeds may also change depending on our ability to receive regulatory approval to establish new branches or acquire other financial institutions.

Our return on equity may be low until we are able to effectively reinvest the additional capital raised in the offering. Until we can increase our net interest income and non-interest income, we expect our return on equity to be below the industry average, which may negatively affect the value of our common stock. See “Risk Factors — Risks Related to the Offering — Our return on equity may be low following the offering, which could negatively affect the trading price of our shares of common stock.”

OUR DIVIDEND POLICY

Columbia Financial has not paid dividends to its minority stockholders due to restrictions contained in Federal Reserve Board regulations applicable to mutual holding companies.

After the completion of the conversion and offering, we intend to pay cash dividends on a quarterly basis. Initially, we expect the quarterly dividends to be $0.05 per share, which equals $0.20 per share on an annualized basis and a 2.0% yield based on a price of $10.00 per share. The initial dividend and continued payment of dividends will depend on a number of factors, including our financial condition and results of operations, tax considerations, capital requirements, alternative uses for capital, the number of shares issued in the offering, industry standards and economic conditions.

There can be no assurance that we will pay dividends in the future, or that any such dividends will not be reduced or eliminated in the future.

Columbia Financial, Inc. will not be permitted to pay dividends on its common stock if its stockholders’ equity would be reduced below the amount of the liquidation account established by Columbia Financial, Inc. in connection with the conversion. The source of dividends will depend on the net proceeds retained by Columbia Financial, Inc. and earnings thereon, and dividends from Columbia Bank. In addition, Columbia Financial, Inc. will be subject to state law limitations and federal bank regulatory policy on the payment of dividends. Maryland law generally limits dividends if the corporation would not be able to pay its debts in the usual course of business after giving effect to the dividend or if the corporation’s total assets would be less than the corporation’s total liabilities plus the amount needed to satisfy the preferential rights upon dissolution of stockholders whose preferential rights on dissolution are superior to those receiving the distribution.

Under OCC regulations, capital distributions by federal savings associations generally include cash dividends and other transactions charged to the capital account of a federal savings association. A federal savings association must file an application with the OCC for approval of the capital distribution if the total capital distributions for the applicable calendar year exceeds the sum of the institution’s net income for that year to date plus the institution’s retained net income for the preceding two years that is still available for dividend; the institution would not be at least adequately capitalized following the distribution; the distribution would violate any applicable statute, regulation, written agreement or regulatory condition; or the institution is not eligible for expedited review of its filings (i.e., generally, institutions that do not have safety and soundness, compliance and Community Reinvestment Act ratings in the top two categories or that fail a capital requirement).

Pursuant to Federal Reserve Board regulations, Columbia Financial, Inc. may not make a distribution that would constitute a return of capital during the three years following the completion of the conversion and offering.

MARKET FOR THE COMMON STOCK

Columbia Financial’s common stock is listed on the Nasdaq Global Select Market under the symbol “CLBK.” Upon completion of the conversion, the shares of common stock of Columbia Financial, Inc. will be exchanged for the existing shares of Columbia Financial and are expected to be listed on the Nasdaq Global Select Market under the symbol “CLBK.”

As of the close of business on April 30, 2026 there were 104,142,951 shares of Columbia Financial common stock outstanding, including 28,126,427 publicly held shares (shares held by stockholders other than Columbia Bank MHC), and on that date Columbia Financial had approximately 3,038 stockholders of record.

As of February 25, 2026 Columbia Financial had approximately 26 registered market makers in its common stock. Keefe, Bruyette & Woods, Inc., Piper Sandler & Co. and Brean Capital, LLC have advised us that they intend to make a market in our common stock following the offering, but none of them is under any obligation to do so.

On January 30, 2026, the business day immediately preceding the public announcement of the conversion and the acquisition of Northfield Bancorp, and on April 30, 2026, the date of this prospectus, the closing prices of Columbia Financial common stock as reported on the Nasdaq Global Select Market were $16.27 per share and $19.23 per share, respectively. On the effective date of the conversion, all publicly held shares of Columbia Financial common stock, including shares of common stock held by our officers and directors, will be converted automatically into and become the right to receive a number of shares of Columbia Financial, Inc. common stock determined pursuant to the exchange ratio. See “The Conversion and Offering — Share Exchange Ratio for Current Stockholders.”

Persons purchasing the common stock may not be able to sell their shares at or above the $10.00 price per share in the offering. Purchasers of our common stock should recognize that there are risks involved in their investment.

HISTORICAL AND PRO FORMA REGULATORY CAPITAL COMPLIANCE

At December 31, 2025, Columbia Financial and Columbia Bank exceeded all regulatory capital requirements. The following tables presents Columbia Financial’s regulatory capital position relative to the regulatory capital requirements at December 31, 2025, on a historical basis, Columbia Financial, Inc.’s regulatory capital position relative to the regulatory capital requirements at December 31, 2025, on a pro forma basis, and Columbia Bank’s regulatory capital position relative to the regulatory capital requirements at December 31, 2025, on a historical and a pro forma basis, with each pro forma basis assuming completion of the proposed merger and the offering. For a discussion of the assumptions underlying the pro forma capital calculations presented below, see “How We Intend to Use the Proceeds of the Offering,” “Capitalization” and “Pro Forma Unaudited Condensed Consolidated Financial Statements Giving Effect to the Conversion and Proposed Merger.” For a discussion of the capital standards applicable to Columbia Financial, Columbia Bank, Northfield Bancorp and Northfield Bank, see “Regulation and Supervision — Federal Banking Regulations.”


						Pro forma (giving effect to the offering and acquisition) at December 31, 2025
(Dollars in thousands)	Columbia Financial					Adjusted Minimum of Offering Range 142,375,000 Shares at $10.00 per share⁽²⁾					Minimum of Offering Range 142,375,000 Shares at $10.00 per share⁽²⁾					Midpoint of Offering Range 167,500,000 Shares at $10.00 per share⁽²⁾					Maximum of Offering Range 192,625,000 Shares at $10.00 per share⁽²⁾
	Amount		Percent of Assets⁽¹⁾			Amount		Percent of Assets⁽²⁾			Amount		Percent of Assets⁽²⁾			Amount		Percent of Assets⁽²⁾			Amount		Percent of Assets⁽²⁾
Capital under generally accepted accounting principals	$	1,160,728		10.53	%	$	2,490,582		14.30	%	$	2,912,052		16.33	%	$	3,153,453		17.45	%	$	3,387,835		18.50	%
Common equity Tier 1 risk- based capital	$	1,117,785		13.94	%	$	2,394,156		19.08	%	$	2,815,625		22.29	%	$	3,057,026		24.11	%	$	3,291,408		25.87	%
Common equity Tier 1 risk- based requirement		521,223		6.50			815,569		6.50			821,048		6.50			824,186		6.50			826,979		6.50	%

Excess	$	596,562		7.44	%	$	1,578,587		12.58	%	$	1,994,578		15.79	%	$	2,232,840		17.61	%	$	2,464,429		19.37	%

Tier 1 risk-based capital	$	1,125,002		14.03	%	$	2,401,373		19.14	%	$	2,822,842		22.35	%	$	3,064,243		24.17	%	$	3,298,625		25.93	%
Tier 1 risk-based requirement		641,506		8.00			1,003,777		8.00			1,010,520		8.00			1,014,383		8.00			1,017,820		8.00	%

Excess	$	483,496		6.03	%	$	1,397,596		11.14	%	$	1,812,322		14.35	%	$	2,049,861		16.17	%	$	2,280,805		17.93	%

Total risk-based capital	$	1,196,057		14.92	%	$	2,472,428		19.71	%	$	2,893,897		22.91	%	$	3,135,298		24.73	%	$	3,369,680		26.49	%
Total risk-based requirement		801,882		10.00			1,254,721		10.00			1,263,150		10.00			1,267,978		10.00			1,272,275		10.00	%

Excess	$	394,175		4.92	%	$	1,217,707		9.71	%	$	1,630,747		12.91	%	$	1,867,320		14.73	%	$	2,097,405		16.49	%

Tier 1 leverage capital	$	1,125,002		10.27	%	$	2,401,373		13.95	%	$	2,822,842		16.01	%	$	3,064,243		17.15	%	$	3,298,625		18.22	%
Tier 1 leverage capital requirement		547,576		5.00			860,457		5.00			881,531		5.00			893,601		5.00			905,320		5.00

Excess	$	577,426		5.27	%	$	1,540,915		8.95	%	$	1,941,311		11.01	%	$	2,170,642		12.15	%	$	2,393,305		13.22	%

(1)	Shown as a percent of assets under generally accepted accounting principles and total assets for leverage ratio and risk-based ratio requirements.

(2)	Reconciliation of capital adjustment for Columbia Financial:


(In thousands)	Adjusted Minimum			Minimum			Midpoint			Maximum
Gross offering proceeds	$	1,423,750		$	1,423,750		$	1,675,000		$	1,926,250
Less: fair value of offering shares issued to Northfield Bancorp stockholders^(a)		(418,001	)		—			—			—
Less: fair value of shares acquired by ESOP		(42,713	)		(42,713	)		(50,250	)		(57,788	)
Less: offering expenses		(39,779	)		(36,311	)		(38,623	)		(43,070	)

Net conversion proceeds		923,257			1,344,726			1,586,127			1,825,392
Disallowed tangible assets as adjusted minimum
Less: increase in disallowed intangible assets relative to level at adjusted minimum		—			—			—			(14,047	)

Increase in Tier 1 capital	$	923,257		$	1,344,726		$	1,586,127		$	1,811,345

Net increase in GAAP assets	$	923,257		$	1,344,726		$	1,586,127		$	1,825,302
Net increase in leverage assets	$	923,257		$	1,344,726		$	1,586,127		$	1,825,392
Net increase risk-based assets^(b)	$	184,651		$	268,945		$	317,225		$	365,078
Total disallowed intangible assets	$	172,392		$	172,392		$	172,392		$	172,392

(a)	Assumes 41,800,140 shares of Columbia Financial, Inc. are issued as merger consideration at the adjusted minimum.

(b)	Assumes proceeds initial invested in assets with 20% risk weight.


						Pro forma (giving effect to the offering and acquisition) at December 31, 2025
(Dollars in thousands)	Columbia Bank					Adjusted Minimum of Offering Range 142,375,000 Shares at $10.00 per share⁽²⁾					Minimum of Offering Range 142,375,000 Shares at $10.00 per share⁽²⁾					Midpoint of Offering Range 167,500,000 Shares at $10.00 per share⁽²⁾					Maximum of Offering Range 192,625,000 Shares at $10.00 per share⁽²⁾
	Amount		Percent of Assets⁽¹⁾			Amount		Percent of Assets⁽²⁾			Amount		Percent of Assets⁽²⁾			Amount		Percent of Assets⁽²⁾			Amount		Percent of Assets⁽²⁾
Capital under generally accepted accounting principals	$	1,102,652		10.01	%	$	2,162,626		11.96	%	$	2,373,361		12.97	%	$	2,490,293		13.52	%	$	2,606,302		14.05	%
Common equity Tier 1 risk- based capital	$	1,058,518		13.20	%	$	2,065,008		16.53	%	$	2,275,743		18.15	%	$	2,392,675		19.05	%	$	2,508,684		19.93	%
Common equity Tier 1 risk- based requirement		521,247		6.50			812,201		6.50			814,941		6.50			816,559		6.50			818,172		6.50	%

Excess	$	537,271		6.70	%	$	1,252,807		10.03	%	$	1,460,802		11.65	%	$	1,576,116		12.55	%	$	1,690,512		13.43	%

Tier 1 risk-based capital	$	1,058,518		13.20	%	$	2,065,008		16.53	%	$	2,275,743		18.15	%	$	2,392,675		19.05	%	$	2,508,684		19.93	%
Tier 1 risk-based requirement		641,534		8.00			999,632		8.00			1,003,004		8.00			1,004,995		8.00			1,006,981		8.00	%

Excess	$	416,984		5.20	%	$	1,065,376		8.53	%	$	1,272,739		10.15	%	$	1,387,680		11.05	%	$	1,501,703		11.93	%

Total risk-based capital	$	1,129,573		14.09	%	$	2,136,063		17.09	%	$	2,346,798		18.72	%	$	2,463,730		19.61	%	$	2,579,739		20.49	%
Total risk-based requirement		801,918		10.00			1,249,540		10.00			1,253,755		10.00			1,256,244		10.00			1,258,727		10.00	%

Excess	$	327,655		4.09	%	$	886,523		7.09	%	$	1,093,043		8.72	%	$	1,207,486		9.61	%	$	1,321,012		10.49	%

Tier 1 leverage capital	$	1,058,518		9.67	%	$	2,065,008		12.18	%	$	2,275,743		13.26	%	$	2,392,675		13.84	%	$	2,508,684		14.41	%
Tier 1 leverage capital requirement		547,536		5.00			847,364		5.00			857,901		5.00			864,124		5.00			870,302		5.00	%

Excess	$	510,982		4.67	%	$	1,217,644		7.18	%	$	1,417,842		8.26	%	$	1,528,551		8.84	%	$	1,638,382		9.41	%

(1)	Shown as a percent of assets under generally accepted accounting principles and total assets for leverage ratio and risk-based ratio requirements.

(2)	Reconciliation of capital adjustment for Columbia Bank:


(In thousands)	Adjusted Minimum			Minimum			Midpoint			Maximum
Gross offering proceeds	$	1,423,750		$	1,423,750		$	1,675,000		$	1,926,250
Less: fair value of offering shares issued to Northfield Bancorp stockholders^(a)		(418,001	)		—			—			—
Less: offering expenses		(39,779	)		(36,311	)		(38,623	)		(43,070	)

Net conversion proceeds		965,970			1,387,439			1,636,377			1,883,180
Equity adjustments
Infused into Columbia Bank (50% of net proceeds)		482,985			693,720			818,189			941,590
Less: ESOP adjustment at bank		(42,713	)		(42,713	)		(50,250	)		(57,788	)

Net increase from offering		440,272			651,007			767,939			883,802
Increase in GAAP capital		440,272			651,007			767,939			883,802
Less: increase in disallowed intangible assets relative to level at adjusted minimum		—			—			—			(14,047	)

Increase in Tier 1 capital	$	440,272		$	651,007		$	767,939		$	869,755

Net increase in GAAP assets	$	482,985		$	693,720		$	818,189		$	941,590
Net increase in leverage assets	$	482,985		$	693,720		$	818,189		$	941,590
Net increase risk-based assets^(b)	$	96,597		$	138,744		$	163,638		$	188,318
Total disallowed intangible assets	$	172,392		$	172,392		$	172,392		$	172,392

(a)	Assumes 41,800,140 shares of Columbia Financial, Inc. are issued as merger consideration at the adjusted minimum.

(b)	Assumes proceeds initial invested in assets with 20% risk weight.

PRO FORMA UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS GIVING EFFECT TO THE CONVERSION AND PROPOSED MERGER

The following pro forma unaudited condensed consolidated statements of financial condition and the pro forma unaudited condensed consolidated statements of income give effect to the proposed offering and the proposed merger, based on the assumptions set forth below. As a result, the pro forma data assumes the completion of the offering and the proposed merger. The condensed pro forma unaudited consolidated financial statements are based, in part, on the audited consolidated financial statements of Columbia Financial for the year ended December 31, 2025 and Northfield Bancorp for the year ended December 31, 2025, respectively. The proforma unaudited condensed consolidated financial statements give effect to the offering at historical cost and the proposed merger using the purchase method of accounting as required by accounting principles generally accepted in the United States of America.

The pro forma adjustments in the tables assume the sale of 167,500,000 shares in the offering, which is the midpoint of the offering range, the issuance of 61,626,877 shares to Columbia Financial’s public stockholders, the issuance of 41,800,140 shares to Northfield Bancorp common stockholders in the merger, and that Northfield Bancorp stockholders will receive $179,143,450 in cash for their shares of Northfield Bancorp. For a more detailed discussion of how many shares will be issued in connection with the offering, see “The Conversion and Offering — Shares Outstanding at Completion of the Offering.”

Pro Forma Unaudited Condensed Consolidated Statement of Financial Condition

As of the Year Ended December 31, 2025 for Historical Data


(In thousands)	Columbia Historical Financial			Offering Adjustments⁽¹⁾			Columbia Financial Pro Forma as Converted			Northfield Bancorp Historical			ESOP Adjustment⁽²⁾			Merger Adjustments⁽³⁾			Columbia Financial Pro Forma
	(Dollars in Thousands)
Assets
Cash and due from banks	$	340,695		$	1,545,089	⁽⁴⁾	$	1,885,784		$	12,051		$	13,860	⁽¹⁰⁾	$	(221,398	)⁽¹¹⁾	$	1,690,297
Interest-earning cash and short-term investments		111			—			111			151,900			—			—			152,011
Trading securities		—			—			—			15,215			—			—			15,215
Debt securities available for sale		1,122,017			—			1,122,017			1,412,419			—			—			2,534,436
Debt securities held to maturity		396,233			—			396,233			8,339			—			(348	)⁽¹²⁾		404,257
Equity securities at fair value		6,802			—			6,802			5,000			—			—			11,802
Federal Home Loan Bank stock, at cost		64,604			—			64,604			46,568			—			—			111,172
Loans receivable net		8,224,809			—			8,224,809			3,818,629			—			(180,110	)⁽¹³⁾		11,863,328
Accrued interest receivable		41,490			—			41,490			20,118			—			—			61,608
Office properties and equipment & ROU asset, net		82,985			—			82,985			45,727			—			—			128,712
Bank-owned life insurance		283,094			—			283,094			182,828			—			—			465,922
Goodwill		110,715			—			110,715			—			—			—	⁽¹⁴⁾		110,715
Core deposit intangible		6,946			—			6,946			—			—			73,265	⁽¹⁵⁾		80,211
Other assets		338,292			—			338,292			35,216			1,444	⁽¹⁰⁾		28,615	⁽¹⁶⁾		403,567

Total assets	$	11,018,793		$	1,545,089		$	12,563,882		$	5,754,010		$	15,304		$	(299,977	)	$	18,033,220

Liabilities
Deposits	$	8,444,079		$	—		$	8,444,079		$	4,015,809		$	—		$	(1,362	)⁽¹⁷⁾	$	12,458,526
Borrowings		1,183,472			—	⁽⁵⁾		1,183,472			961,881			—			151	⁽¹⁸⁾		2,145,504
Advance payments by borrowers for taxes and insurance		45,792			—			45,792			20,276			—			—			66,068
Accrued interest and other liabilities		184,722			—			184,722			65,985			—			—			250,707

Total liabilities		9,858,065			—			9,858,065			5,063,951			—			(1,211	)		14,920,805

Stockholders’ equity
Common stock		1,316			975	⁽⁶⁾		2,291			648			—			(230	)⁽¹⁹⁾		2,709
Additional paid in capital		806,581			1,159,269	⁽⁷⁾		1,965,850			592,473			7,481			(182,371	)⁽¹⁹⁾		2,383,433
Retained earnings		933,717			—			933,717			420,405			(3,905	)⁽¹⁰⁾		(427,904	)⁽²⁰⁾		922,313
Accumulated other comprehensive loss		(75,972	)		—			(75,972	)		(4,220	)		—			4,220	⁽¹⁹⁾		(75,972	)
Treasury stock, at cost		(476,133	)		476,133	⁽⁷⁾		—			(307,519	)		—			307,519	⁽¹⁹⁾		—
Employee stock ownership plan		(27,935	)		(50,250	)⁽⁸⁾		(78,185	)		(11,728	)		11,728	⁽¹⁰⁾		—			(78,185	)
Stock held by Rabbi Trust		(3,479	)		(41,038	)⁽⁹⁾		(44,517	)		—			—			—			(44,517	)
Deferred compensation obligation		2,633			—			2,633			—			—			—			2,633

Total equity		1,160,728			1,545,089			2,705,817			690,059			15,304			(298,766	)		3,112,415

Total liabilities and equity	$	11,018,793		$	1,545,089		$	12,563,882		$	5,754,010		$	15,304		$	(299,977	)	$	18,033,220

(1)

Shows the effect of the second-step conversion of Columbia Financial, assuming gross proceeds of $1.675 billion at the midpoint of the valuation range, offering expenses of $38.6 million, extension of a second loan to the Columbia Bank Employee Stock Ownership Plan (the “Columbia Bank ESOP”) and establishment of a stock-based benefit plan that will acquire 3.0% and 2.45% of total shares sold in the offering, respectively. The Columbia Bank ESOP will purchase its shares in the offering and possibly in open market purchases. The stock-based benefit plan will purchase shares in the open market after receiving stockholder approval to adopt the plan. Open market purchases by the Columbia Bank ESOP stock-based benefit plan are assumed at $10.00 per share.

(2)	Impact of terminating the Northfield Bank ESOP at closing assuming an acquisition price of $14.25 in cash and stock merger consideration.

(3)	Reflects the purchase accounting and acquisition adjustments related to the acquisition of Northfield Bancorp for a price of $14.25 in cash and stock merger consideration.

(4)	Calculated as follows (in thousands):


Gross proceeds of offering	$	1,675,000
Estimated expenses		(38,623	)
Common stock acquired by ESOP		(50,250	)
Common stock acquired by stock-based benefit plan		(41,038	)

Pro forma adjustment	$	1,545,089

(5)	The ESOP loan is funded internally with a loan from Columbia Financial, thus no borrowing liability is recorded on the consolidated balance sheet of Columbia Financial.

(6)	Par value $0.01 per share on shares issued by Columbia Financial, Inc. in the second step conversion offering (in thousands).


Total shares issued in second-step conversion (including exchange shares issued to Columbia Financial public stockholders)		229,126,877
Par Value of $0.01 per share	$	2,291
Less: Historical Par Value		(1,316	)

Pro forma Adjustment	$	975

(7)	Calculated as follows (in thousands):


Net cash proceeds of second-step conversion	$	1,634,086
Less: Eliminate treasury stock balance		(476,133	)
Plus: Historical par value		1,316

Pro forma adjustment	$	1,159,269

(8)	Contra-equity account established to reflect the obligation to repay the loan to the ESOP.

(9)	Contra-equity account established to reflect the stock-based benefit plan.

(10)	Reflects the termination of the Northfield Bancorp’s ESOP (in thousands).


Adjustment to assets
Cash received from termination of ESOP at closing	$	13,860
Deferred tax asset recorded with the compensation expense of termination of the ESOP		1,444

Net impact to total assets	$	15,304

Adjustments to stockholders’ equity
Compensation expense to record after-tax expense of ESOP termination	$	(3,905	)
Plus: Addition to paid-in capital		7,481
Plus: Elimination of ESOP contra-equity account		11,728

Net impact to stockholders’ equity	$	15,304

(11)	Includes the cash consideration paid to stockholders of Northfield Bancorp, assuming 30% of the merger consideration is paid in cash, non-tax deductible transaction expenses and tax deductible transaction expenses (in thousands).


Cash merger consideration	$	179,143
Columbia merger costs expenses (after tax)		35,904
Northfield Bancorp merger costs included in goodwill (after tax)		6,351

Total cash adjustment	$	221,398

(12)	Reflects the fair value adjustments on held-to-maturity investments.

(13)

Reflects the reversal of the December 31, 2025 allowance for credit losses of Northfield Bancorp and a fair value adjustment applied to the acquired loans (in thousands). The fair value adjustment includes a credit component and a yield component. The credit component includes the estimated credit losses embedded in the acquired loans as of December 31, 2025. The yield component reflects the differences between market and portfolio yields as of December 31, 2025. The fair value adjustment attributable to the yield component will be accreted into income over the lives of the related loans.


Reversal of Northfield Bancorp allowances	$	38,144
Fair value adjustment — yield component		(137,254	)
Fair value adjustment — credit component		(81,000	)

Pro forma adjustment	$	(180,110	)

(14)	Based on the transaction characteristics, Columbia Financial, Inc. will record a bargain purchase gain (no goodwill) calculated as follows (in thousands, except share amounts):


	Adjustments to Net Assets Acquired			Estimate of Bargain Purchase Gain
Purchase price per share				$	14.25
Number of Northfield shares acquired					41,904,902
Purchase price, net				$	597,145
Acquired stockholders’ equity	$	690,059
Plus: After tax impact of ESOP termination		15,304
Northfield merger costs (after-tax)		(6,351	)
Taxable purchase accounting adjustments:
Fair value adjustment for held-to-maturity investments		(348	)
Fair value adjustment for acquired loans (yield)		(137,254	)
Fair value adjustment for acquired loans (credit)		(81,000	)
Reverse allowance for credit losses		38,144
Core deposit intangible adjustment		73,265
Fair value adjustment for acquired CDs		1,362
Fair value adjustment for acquired borrowed funds		379
Fair value adjustment for acquired subordinated debt		(228	)
Tax effect at the marginal tax rate at 27%		28,615

Less: fair value of net assets					621,645

Pro forma goodwill/(negative goodwill)				$	(24,500	)
Bargain purchase gain recorded to retained earnings on recognition of negative goodwill				$	24,500

(15)

Core deposit intangible asset representing the economic value of the acquired Northfield Bancorp core deposit base, calculated as the present value benefit of funding operations with the acquired core deposit base versus using an alternative wholesale funding source. The core deposit intangible asset is amortized into expense over the estimated life of the core deposit base.

(16)	Deferred tax entry consists of fair value adjustment at a 27% effective tax rate.

(17)

Fair value adjustment to reflect the difference between portfolio costs and market rates as of December 31, 2025 for time deposits acquired in the merger. Yield adjustment is estimated using present value analysis and the fair value adjustment is amortized into expense over the lives of the related time deposits.

(18)

Fair value adjustment to reflect the difference between portfolio costs and market rates as of December 31, 2025 for borrowed funds acquired in the merger (in thousands). Yield adjustment is estimated using present value analysis and the fair value adjustment is amortized into expense over the lives of the related time deposits.


Record fair value adjustment on borrowed funds	$	379
Record fair value adjustment on subordinated debt		(228	)

Net adjustment to borrowed funds	$	151

(19)	Adjustment to eliminate the historical Northfield Bancorp capital account entries and additional paid in capital from stock issued as merger consideration (in thousands).


Adjustment to common stock
Eliminate Northfield Bancorp’s historical paid in capital	$	(648	)
Paid in capital on shares issued as merger consideration		418

Net adjustment to common stock				$	(230	)
Adjustment to paid in capital
Eliminate Northfield Bancorp’s historical common stock	$	(592,473	)
Plus: Value of stock issued as merger consideration to Northfield Bancorp^(a)		418,001
Less: Paid in capital from termination of Northfield Bank ESOP		(7,481	)
Less: Amounts ascribed to paid in capital (see adjustment above)		(418	)

Net adjustment to paid in capital				$	(182,371	)
Adjustment to eliminate Northfield Bancorp’s accumulated other comprehensive loss				$	4,220
Adjustment to eliminate Northfield Bancorp’s Treasury stock, at cost				$	307,519

(a)	Assumes 70% of the merger consideration is paid in shares of Columbia Financial, Inc.

(20)	Adjustments to retained earnings as follows (in thousands):


Eliminate historical Northfield Bancorp retained earnings	$	(420,405	)
Eliminate retained earnings from Northfield Bancorp ESOP termination		3,905
Record bargain purchase gain realized by Columbia Financial		24,500
Record Columbia Financial after tax merger costs		(35,904	)

Net adjustment to retained earnings	$	(427,904	)

Pro Forma Unaudited Condensed Consolidated Statement of Income

For the Year Ended December 31, 2025 for Historical Data


	Columbia Historical Financial			Offering Adjustments⁽¹⁾			Columbia Financial Pro Forma as Converted			Northfield Bancorp Historical⁽³⁾			Merger Adjustments⁽⁴⁾			Columbia Financial Pro Forma
	(Dollars in thousands)
Interest and dividend income	$	470,951		$	—		$	470,951		$	249,096		$	35,533	⁽⁵⁾	$	755,580
Interest expense		(249,317	)		—			(249,317	)		(111,730	)		(417	)⁽⁶⁾		(361,464	)

Net interest income		221,634			—			221,634			137,366			35,116			394,116
Provision for loan losses		(9,822	)		—			(9,822	)		(7,402	)		—			(17,224	)

Net interest income after provision for loan losses		211,812			—			211,812			129,964			35,116			376,892
Noninterest income		37,069			—			37,069			16,950			(942	)⁽⁷⁾		53,077
Noninterest expense		(180,892	)		(2,010	)⁽²⁾		(182,902	)		(129,863	)		(12,147	)⁽⁸⁾		(324,912	)

Income before income taxes		67,989			2,010			65,979			17,051			22,027			105,057
Income tax expense		(16,223	)		543			(15,680	)		(16,255	)		(6,052	)⁽⁹⁾		(37,987	)

Net income	$	51,766		$	(1,467	)	$	50,299		$	796		$	15,975		$	67,070

Basic shares outstanding		101,810,752			—			224,339,992						—			261,316,132
Diluted shares outstanding		101,810,752			—			224,339,992						—			261,316,132
Basic EPS⁽⁹⁾	$	0.51		$	—		$	0.22		$	0.02		$	—		$	0.26
Diluted EPS⁽⁹⁾	$	0.51		$	—		$	0.22		$	0.02		$	—		$	0.26

(1)

Shows the effect of the second-step conversion of Columbia Financial, assuming gross proceeds of $1.675 billion, at the midpoint of the offering range, offering expenses of $38.6 million, and extension of a second loan to the Columbia Bank ESOP, which will acquire 3.0% of the offering. The Columbia Bank ESOP will purchase shares in the offering and in open market purchases. The loan taken out by the Columbia Bank ESOP will be amortized over 25 years on a straight-line basis. The ESOP expense shown reflects the estimated amortization expense on a pretax basis for the period shown. Columbia Financial, Inc. also intends to adopt a stock-based benefit plan that will purchase 2.45% of the offering. The stock-based benefit plan will purchase shares in the open market after receiving stockholder approval. Open market purchases are assumed at $10 per share. Columbia Financial, Inc. also intends to adopt a stock option plan that will include 6.20% of the offering plus foundation shares issued in the transaction Pursuant to an application of the Black-Scholes option pricing model, the stock options are assumed to have a value of $3.20 per option. The option value is assumed to be expensed over the seven-year vesting period for the options and 25% of the option expense is assumed to be deductible for income tax purposes. The stock option plan is subject to stockholder approval. Adjustments to record estimated stock-based benefit plan expense, stock option plan expense, and interest income to be earned on net proceeds of the offering will be recorded as incurred. Since these estimates are speculative, they are not reflected in the calculations of pro forma income. The estimated interest income, assuming net cash proceeds of $1.545 billion from the offering are invested at an average pre-tax yield of 3.73% for the year ended December 31, 2025 would be approximately $57.6 million on a pre-tax basis. The yield utilized approximates the yield on a five-year U.S. Treasury security as of December 31, 2025. The estimated expense for the stock-based benefit plan assuming gross proceeds of $1.675 billion is $5.9 million pretax for the year ended December 31, 2025. The estimated expense for the stock option plan assuming gross proceeds of $1.675 billion is $5.1 million pre-tax for the year ended December 31, 2025. The ESOP loan is amortized over 25 years on a straight-line basis assumed marginal rate of 27.0%. No expenses are included for merger-related charges, all of which are one-time expenses.

(2)

ESOP loan with a balance of $50.25 million and an amortization period of 25 years, straight line. ESOP loan is assumed to be funded internally, so no interest expense is recorded on the consolidated income statement for Columbia Financial. ESOP expense thus reflects only the amortization of principal for the period shown.

(3)	Northfield Bancorp’s historical earnings includes a non-cash goodwill impairment charge of $41.0 million.

(4)	Reflects the purchase accounting and acquisition adjustments related to the acquisition of Northfield Bancorp for a price of $ 14.25 in cash and stock.

(5)

Adjustment to interest income is the accretion of the fair value adjustment on the Northfield Bancorp loans and investments resulting from acquisition accounting. Interest income to be foregone as a result of funding the cash portion of the merger consideration and expenses of the acquisition will be recorded as incurred. Because they are non-recurring, these expenses are not reflected in the pro forma income statements. The estimated reduction in interest income assuming funding requirements of $207.5 million for the merger and related expenses, assuming such cash costs were funded with investments yielding 3.73% for the year ended December 31, 2025 would be approximately $7.7 million. The interest cost approximates the yield on the five-year U.S. Treasury security as of December 31, 2025.

(6)	Adjustment to interest expense is the amortization of the fair value adjustment on deposits and borrowed funds.

(7)	Reduction of fee income as Northfield Bancorp historical fee income is limited by the Durbin Amendment limitations on fee income.

(8)	Adjustment to non-interest expense is the amortization of the core deposit intangible over 10 years using the sum of the years’ digits amortization method net of a $1.174 million annual pre-tax reduction in Northfield Bank ESOP expense resulting from the termination of the Northfield Bank ESOP.

(9)

Assumes a marginal tax rate of 27.0% on pre-tax income. The adjustment also includes the estimated impact of the loss of a portion of the real estate investment trust tax benefit realized by Northfield Bancorp on a historical basis owing to the increase in total assets in excess of $8 billion estimated to equal $0.144 million annually on a pre-tax basis.

CAPITALIZATION

The following table presents the historical capitalization of Columbia Financial and Northfield Bancorp at December 31, 2025 and the capitalization of Columbia Financial, Inc. after giving effect to the receipt of the offering proceeds and the proposed merger (referred to as “pro forma” information). The table depicts adjustments to capitalization resulting first from the offering and then from the proposed merger only at the minimum of the offering range and then depicts Columbia Financial, Inc.’s capitalization following the offering and the proposed merger at the adjusted minimum, minimum, midpoint and maximum of the offering range. The pro forma capitalization gives effect to the assumptions listed under “Pro Forma Unaudited Condensed Consolidated Financial Statements Giving Effect to the Conversion and the Proposed Merger.”


																			Pro Forma Capitalization Based Upon the Sale of
(Dollars in thousands)	Columbia Financial, Inc.			Offering Adjustments: 142,375,000 at Minimum of Offering Range			Columbia Financial, Inc. Post-offering			Northfield Bancorp			ESOP Adjustment			Merger Adjustments			Adjusted Minimum 142,375,000 Shares at $10.00 per share			Minimum 142,375,000 Shares at $10.00 per share			Midpoint 167,500,000 Shares at $10.00 per share			Maximum 192,625,000 Shares at $10.00 per Share
Deposits⁽¹⁾	$	8,444,079		$	—		$	8,444,079		$	4,015,809		$	—		$	(1,362	)	$	12,458,526		$	12,458,526		$	12,458,526		$	12,458,526
Borrowings		1,183,472			—			1,183,472			961,881			—			151			2,145,504			2,145,504			2,145,504			2,145,506

Total deposits and borrowed funds	$	9,627,551		$	—		$	9,627,551		$	4,977,690		$	—		$	(1,211	)	$	14,604,030		$	14,604,030		$	14,604,030		$	14,604,030

Stockholders’ equity:
Preferred stock	$	—		$	—		$	—		$	—		$	—		$	—		$	—		$	—		$	—		$	—
Common stock⁽²⁾		1,316			632			1,948			648			7,481			(648	)		1,948			2,366			2,709			3,065
Additional paid-in capital		806,581			489,205			1,295,786			592,473			(3,905	)		(181,953	)		1,713,787			2,134,838			2,383,433			2,624,997
Retained earnings		933,717			—			933,717			420,405			—			(427,904	)		922,313			922,313			922,313			922,313
Accumulated other comprehensive income (loss)		(75,972	)		—			(75,972	)		(4,220	)		—			4,220			(75,972	)		(75,972	)		(75,972	)		(75,972	)
Less: treasury stock		(476,133	)		476,133			—			(307,519	)		—			307,519			—			—			—			—
Less: common stock owned by employee stock ownership plan		(27,935	)		—			(27,935	)		—			—			—			(27,935	)		(27,935	)		(27,935	)		(27,935	)
Less: common stock acquired by employee stock ownership plan⁽³⁾		—			(42,713	)		(42,713	)		(11,728	)		11,728			—			(42,713	)		(42,713	)		(50,250	)		(57,788	)
Less: common stock held by Rabbi Trust		(3,479	)		—			(3,479	)		—			—			—			(3,479	)		(3,479	)		(3,479	)		(3,479	)
Less: common stock acquired by restricted stock-based benefit plan⁽⁴⁾		—			(34,882	)		(34,882	)		—			—			—			(34,882	)		(34,882	)		(41,038	)		(47,193	)
Less: deferred compensation obligation		2,633			—			2,633			—			—			—			2,633			2,633			2,633			2,633

Total stockholders’ equity	$	1,160,728		$	888,375		$	2,049,103		$	690,059		$	15,304		$	(298,766	)	$	2,455,700		$	2,877,170		$	3,112,415		$	3,340,642

Proforma shares outstanding:
Shares offered for sale in the second step conversion		—			100,574,860			100,574,860			—			—			—			100,574,860			142,375,000			167,500,000			192,625,000
Exchange shares issued to Columbia Financial stockholders		—			52,382,845			52,382,845			—			—			—			52,382,845			52,382,845			61,626,877			70,870,908
Shares issued to stockholders of Northfield Bancorp in the offering⁽⁵⁾		—			41,800,140			41,800,140			—			—			—			41,800,140			—			—			—
Shares issued to stockholders of Northfield Bancorp		—			—			—			—			—			—			—			41,800,140			41,800,140			42,973,477


																Pro Forma Capitalization Based Upon the Sale of
(Dollars in thousands)	Columbia Financial, Inc.			Offering Adjustments: 142,375,000 at Minimum of Offering Range		Columbia Financial, Inc. Post-offering			Northfield Bancorp			ESOP Adjustment		Merger Adjustments		Adjusted Minimum 142,375,000 Shares at $10.00 per share			Minimum 142,375,000 Shares at $10.00 per share			Midpoint 167,500,000 Shares at $10.00 per share			Maximum 192,625,000 Shares at $10.00 per Share
Total shares outstanding					194,757,845		194,757,845			—			—		—		194,757,845			236,557,985			270,972,017			306,469,385
Total stockholders’ equity as a percentage of pro forma total assets		10.53	%		—		17.21	%		11.99	%		—		—		14.13	%		16.17	%		17.26	%		18.29	%
Tangible stockholders’ equity as a percentage of pro forma tangible assets		9.57	%		—		16.38	%		11.99	%		—		—		13.18	%		15.26	%		16.37	%		17.43	%

(1)	Does not reflect withdrawals from deposit accounts Columbia Bank to purchase common stock in the offering. These withdrawals will reduce pro forma deposits by the amounts of the withdrawals.

(2)

No effect has been given to the issuance of additional shares of common stock pursuant to the exercise of options under a stock-based benefit plan. If the plan is implemented within the first year after the closing of the offering, an amount up to 6.20% of the shares of common stock of Columbia Financial, Inc. offered in the offering will be reserved for issuance upon the exercise of options under the plans.

(3)

Assumes that 3.0% of the shares of common stock of Columbia Financial, Inc. offered in the offering will be acquired by the Columbia Bank ESOP financed by a loan from Columbia Financial, Inc. The loan will be repaid principally from Columbia Bank’s contributions to the employee stock ownership plan. Since Columbia Financial, Inc. will finance the ESOP debt, this debt will be eliminated through consolidation and no liability will be reflected on Columbia Financial, Inc.’s consolidated balance sheet. Accordingly, the number of shares of common stock acquired by the Columbia Bank ESOP is shown in this table as a reduction of total stockholders’ equity.

(4)

Assumes a number of shares of common stock equal to 2.45% of the shares of common stock of Columbia Financial, Inc. offered in the offering and at the completion of the offering will be purchased for grant by a stock-based benefit plan. The funds to be used by such plan to purchase shares will be provided by Columbia Financial, Inc. The dollar amount of common stock to be purchased is based on the $10.00 per share offering price and represents unearned compensation. This amount does not reflect possible increases or decreases in the value of common stock relative to the offering price. Columbia Financial, Inc. will accrue compensation expense to reflect the vesting of shares granted pursuant to such stock-based benefit plan and will credit capital in an amount equal to the charge to operations. Implementation of such plan will require stockholder approval.

(5)	Assumes 41,800,140 shares of Columbia Financial, Inc. are issued as merger consideration at the adjusted minimum.

PRO FORMA DATA

The following table illustrates the pro forma impact of the conversion and offering on our net income and stockholders’ equity based on the sale of common stock at the adjusted minimum, minimum, the midpoint and the maximum of the offering range. The actual net proceeds from the sale of the common stock cannot be determined until the offering is completed. Net proceeds indicated in the following tables are based upon the following assumptions, although actual expenses may vary from these estimates:

•

The pro forma data incorporates the following assumptions as to the sale of stock in the subscription, community and firm commitment underwritten offerings as a percentage of the total stock sold in the offerings.


	Shares Sold in the Offering
Shares Sold	Adjusted Minimum			Minimum			Midpoint			Maximum
Shares sold to insiders and benefit plans⁽¹⁾		3.18	%		3.18	%		3.15	%		3.13	%
Subscription offering⁽²⁾		37.47	%		61.82	%		61.85	%		61.87	%
Community offering⁽³⁾		29.36	%		5.00	%		5.00	%		5.00	%
Firm commitment underwritten offering		30.00	%		30.00	%		30.00	%		30.00	%

Total common shares issued in the offering⁽³⁾		100.00	%		100.00	%		100.00	%		100.00	%

(1)	Includes shares sold to the employee stock ownership plan, tax-qualified or stock-based compensation plans or to our officers, directors and employees or members of their immediate families.

(2)	Excludes shares sold to insiders and benefit plans as described in footnote (1).

(3)	Includes 41,800,140 merger shares issued to Northfield Bancorp stockholders at the adjusted minimum of the offering range.

•

Our employee stock ownership plan will purchase a number of shares equal to 3.0% of the shares sold in the offering with a loan from Columbia Financial, Inc. that will be repaid in equal installments over 25 years.

•

We will pay Keefe, Bruyette & Woods, Inc. a success fee equal to 1.0% of the aggregate amount of common stock sold in the subscription offering, except that no fee will be paid with respect to shares purchased by our employee stock ownership plan, tax-qualified or stock based compensation plans or similar and by our officers, directors and employees or members of their immediate families and we will pay a fee equal to 2.0% of the aggregate purchase price of common stock sold in the community offering, including any merger shares issued in connection with the adjusted minimum.

•

We will pay Keefe, Bruyette & Woods, Inc. and others participating in the syndicate of registered broker dealers who sell stock in a firm commitment underwritten offering a fee as a percentage of the gross proceeds of stock sold in the firm commitment underwritten offering equal to 5.0% if the transaction proceeds are less than $300 million, 4.0% if the transaction proceeds is between $300 million and $500 million, 3.5% if the transaction proceeds is between $500 million and $700 million, and 3.15% if the transaction process in excess of $700 million.

•

Total expenses of the offering, excluding selling agent commissions and expenses, will be approximately $8.45 million.

We calculated pro forma consolidated net income for the year ended December 31, 2025 as if the estimated net investable proceeds had been invested at an assumed interest rate of 3.73% (2.72% on an after-tax basis using an assumed tax rate of 27%). This represents the yield on the five-year United States Treasury Note at December 31, 2025 which, in light of current market interest rates, we consider to more accurately reflect the pro forma reinvestment rate than the arithmetic average of the weighted average yield earned on our interest-earning assets and the weighted average rate paid on our deposits, which is the reinvestment rate generally required by federal banking regulators.

We calculated historical and pro forma per share amounts by dividing historical and pro forma consolidated net income and stockholders’ equity by the indicated number of shares of common stock. We computed per share amounts as if the shares of common stock were outstanding at the beginning of the period, but we did not adjust per share historical or pro forma stockholders’ equity to reflect the earnings on the estimated net proceeds.

The pro forma table gives effect to the implementation of a new stock-based benefit plan. We have assumed that the stock-based benefit plan will acquire for restricted stock awards a number of shares of common stock equal to 2.45% of the shares of common stock sold in the offering at the same price for which they were sold in the offering. We have assumed that awards of common stock granted under such plan will vest ratably over a seven-year period.

We also have assumed that options will be granted under stock-based benefit plan to acquire shares of common stock equal to 6.20% of the shares of common stock sold in the offering. In preparing the table below, we assumed that stockholder

approval was obtained, that the exercise price of the stock options and the market price of the stock at the date of grant were $10.00 per share and that the stock options had a term of ten years and vested over seven years. We applied the Black-Scholes option pricing model to estimate a grant-date fair value of $3.20 for each option.

As discussed under “How We Intend to Use the Proceeds of the Offering,” we intend to contribute 50% of the net offering proceeds to Columbia Bank, and we will retain the remainder of the net proceeds from the offering. We will use a portion of the proceeds we retain to fund a loan to the employee stock ownership plan and retain the rest of the proceeds for future use.

The pro forma table does not give effect to:

•

withdrawals from deposit accounts to purchase shares of common stock in the offering;

•

our results of operations after the offering; or

•

changes in the market price of the shares of common stock after the offering.

The following pro forma information may not be representative of the financial effects of the offering at the date on which the offering actually occurs, and should not be taken as indicative of future results of operations. Pro forma consolidated stockholders’ equity represents the difference between the stated amounts of our assets and liabilities. The pro forma stockholders’ equity is not intended to represent the fair market value of the shares of common stock and may be different than the amounts that would be available for distribution to stockholders if we liquidated. Moreover, pro forma stockholders’ equity per share does not give effect to the liquidation accounts to be established in the conversion or, in the unlikely event of a liquidation of Columbia Bank, to the tax effect of the recapture of the bad debt reserve. See “The Conversion and Offering — Liquidation Rights.”


	At or for the Year Ended December 31, 2025 Based upon the Sale at $10.00 Per Share of
(Dollars in thousands)	Adjusted Minimum 142,375,000 Shares			Minimum 142,375,000 Shares			Midpoint 167,500,000 Shares			Maximum 192,625,000 Shares
Gross proceeds of offering	$	1,423,750		$	1,423,750		$	1,675,000		$	1,926,250
Plus: market value of shares issued in the exchange		523,828			523,828			616,269			708,709
Plus: fair value of shares issued in merger		418,001			418,001			418,001			429,735
Less: fair value of offering shares issued to Northfield Bancorp stockholders		(418,001	)		—			—			—

Pro forma value including merger shares	$	1,947,578		$	2,365,580		$	2,709,270		$	3,064,694

Gross proceeds of offering	$	1,423,750		$	1,423,750		$	1,675,000		$	1,926,250
Less: estimated expenses		(39,779	)		(36,311	)		(38,623	)		(43,070	)
Less: fair value of offering shares issued to Northfield Bancorp stockholders		(418,001	)		—			—			—

Estimated net proceeds		965,970			1,387,439			1,636,377			1,883,180
Less: common stock acquired by employee stock ownership plan⁽¹⁾		(42,712	)		(42,712	)		(50,250	)		(57,788	)
Less: common stock to be acquired by stock-based benefit plan⁽²⁾		(34,882	)		(34,882	)		(41,038	)		(47,193	)

Net investable proceeds from offering	$	888,376		$	1,309,845		$	1,545,089		$	1,778,199

Funds required to effect the merger	$	(207,538	)	$	(207,538	)	$	(207,538	)	$	(212,567	)
Consolidated pro forma net income
Pro forma net income
Historical Columbia Financial	$	51,766		$	51,766		$	51,766		$	51,766
Pro forma income on net investable proceeds		24,190			35,666			42,071			48,419
Pro forma impact of funding the merger		(5,651	)		(5,651	)		(5,651	)		(5,788	)
Pro forma employee stock ownership plan adjustments⁽¹⁾		(1,247	)		(1,247	)		(1,467	)		(1,687	)
Pro forma restricted stock award expense⁽²⁾		(3,638	)		(3,638	)		(4,280	)		(4,922	)
Pro forma stock option expense⁽³⁾		(3,763	)		(3,763	)		(4,427	)		(5,091	)
Estimated merger adjustments		16,771			16,771			16,771			16,771

Pro forma net income	$	78,428		$	89,904		$	94,783		$	99,468


	At or for the Year Ended December 31, 2025 Based upon the Sale at $10.00 Per Share of
(Dollars in thousands)	Adjusted Minimum 142,375,000 Shares			Minimum 142,375,000 Shares			Midpoint 167,500,000 Shares			Maximum 192,625,000 Shares
Pro forma net income per share
Historical Columbia Financial	$	0.28		$	0.23		$	0.21		$	0.19
Pro forma income on net investable proceeds		0.13			0.16			0.16			0.16
Pro forma impact of funding the merger		(0.03	)		(0.02	)		(0.02	)		(0.02	)
Pro forma employee stock ownership plan adjustments⁽¹⁾		(0.01	)		(0.01	)		(0.01	)		(0.01	)
Pro forma restricted stock award expense⁽²⁾		(0.02	)		(0.02	)		(0.02	)		(0.02	)
Pro forma stock option expense⁽³⁾		(0.02	)		(0.02	)		(0.02	)		(0.02	)
Estimated merger adjustments		0.09			0.07			0.06			0.06

Pro forma net income	$	0.42		$	0.39		$	0.36		$	0.34

Offering price as a multiple of proforma net income per share		23.81x			25.64x			27.78x			29.41x

Number of shares used to calculate pro forma net income per share^(4)(5)(6)		186,580,957			228,381,097			261,316,132			295,414,323


	At or for the Year Ended December 31, 2025 Based upon the Sale at $10.00 Per Share of
(Dollars in thousands)	Adjusted Minimum 142,375,000 Shares			Minimum 142,375,000 Shares			Midpoint 167,500,000 Shares			Maximum 192,625,000 Shares
Pro forma stockholders’ equity:
Historical Columbia Financial	$	1,160,728		$	1,160,728		$	1,160,728		$	1,160,728
Estimated net proceeds		965,970			1,387,439			1,636,377			1,883,180
Less: common stock acquired by employee stock ownership plan⁽¹⁾		(42,712	)		(42,712	)		(50,250	)		(57,788	)
Less: common stock acquired by stock-based benefit plan⁽²⁾		(34,882	)		(34,882	)		(41,038	)		(47,193	)
Estimated merger adjustments		406,598			406,598			406,598			401,715

Pro forma stockholders’ equity		2,455,701			2,877,170			3,112,415			3,340,642
Intangible assets		(190,926	)		(190,926	)		(190,926	)		(190,926	)

Pro forma tangible stockholders’ equity	$	2,264,776		$	2,686,245		$	2,921,489		$	3,149,716

Pro forma stockholders’ equity per share:
Historical Columbia Financial	$	5.96		$	4.90		$	4.29		$	3.79
Estimated net proceeds		4.96			5.87			6.04			6.14
Less: common stock acquired by employee ownership plan⁽¹⁾		(0.22	)		(0.18	)		(0.19	)		(0.19	)
Less: common stock acquired by stock-based benefit plan⁽²⁾		(0.18	)		(0.15	)		(0.15	)		(0.15	)
Estimated merger adjustments		2.09			1.72			1.50			1.31

Pro forma stockholders’ equity per share		12.61			12.16			11.49			10.90
Intangible assets		(0.98	)		(0.80	)		(0.71	)		(0.62	)

Pro forma tangible stockholders’ equity per share	$	11.63		$	11.36		$	10.78		$	10.28

Offering price as a percentage of pro forma equity per share		79.30	%		82.24	%		87.03	%		91.74	%
Offering price as a percentage of pro forma tangible equity per share		85.98	%		88.03	%		92.76	%		97.28	%
Shares used for pro forma stockholders’ equity per share^(4)(5)(6)		194,757,845			236,557,985			270,927,017			306,469,385

(1)

Assumes that 3.0% of the shares of common stock sold in the offering will be purchased by the Columbia Bank ESOP. For purposes of this table, the funds used to acquire these shares are assumed to have been borrowed by the employee stock ownership plan from Columbia Financial, Inc. Columbia Bank intends to make annual contributions to the Columbia Bank ESOP in an amount at least equal to the required principal and interest payments on the debt. Columbia Bank’s total annual payments on the employee stock ownership plan debt are based upon 25 equal annual installments of principal and interest. Financial Accounting Standards Board Accounting Standards Codification (“ASC”) 718-40, “Compensation — Stock Compensation — Employee Stock Ownership Plans” (“ASC 718-40”) requires that an employer record compensation expense equal to the fair value of the shares committed to be released to employees. The pro forma adjustments assume that the Columbia Bank ESOP shares are allocated in equal annual installments based on the number of loan repayment installments assumed to be paid by Columbia Bank, the fair value of the common stock remains equal to the subscription price and the employee stock ownership plan expense reflects an effective combined federal and state tax rate of 27.0%. The unallocated Columbia Bank ESOP shares are reflected as a reduction of stockholders’ equity. No reinvestment is assumed on proceeds contributed to fund the Columbia Bank ESOP. In accordance with ASC 718-40, only the Columbia Bank ESOP shares committed to be released during the period were considered outstanding for net income per share calculations.

(2)

Assumes that a new stock-based benefit plan purchases an aggregate number of shares of common stock equal to 2.45% of the shares to be sold in the offering. Stockholder approval of the plan and purchases by the plan may not occur earlier than six months after the completion of the conversion. The shares may be acquired directly from Columbia Financial, Inc. or through open market purchases. Shares in the stock-based benefit plan are assumed to vest over a period of seven years. The funds to be used to purchase the shares will be provided by Columbia Financial, Inc. The table assumes that (i) the stock-based benefit plan acquires the shares through open market purchases at $10.00 per share, (ii) 14.29% of the amount contributed to the plan is amortized as an expense during the year ended December 31, 2025, and (iii) the plan expense reflects an effective tax rate of 27%. Assuming stockholder approval of the stock-based benefit plan and that shares of common stock (equal to 2.45% of the shares sold in the offering) are awarded through the use of authorized but unissued shares of common stock, stockholders would have their ownership and voting interests diluted by approximately 1.76%, 1.45%, 1.49% and 1.52% at the adjusted minimum, minimum, midpoint and maximum of the offering range, respectively.

(3)

Assumes that options are granted under a new stock-based benefit plan to acquire an aggregate number of shares of common stock equal to 6.20% of the shares to be sold in the offering. Stockholder approval of the plan may not occur earlier than six months after the completion of the conversion. In calculating the pro forma effect of the stock-based benefit plans, it is assumed that the exercise price of the stock options and the trading price of the common stock at the date of grant were $10.00 per share, the estimated grant-date fair value determined using the Black-Scholes option pricing model was $3.20 for each option, the aggregate grant-date fair value of the stock options was amortized to expense on a straight-line basis over a seven-year vesting period of the options, and that 25% of the amortization expense (or the assumed portion relating to options granted to directors) resulted in a tax benefit using an assumed tax rate of 27%. The actual expense will be determined by the grant-date fair value of the options, which will depend on a number of factors, including the valuation assumptions used and the option pricing model ultimately adopted. Under the above assumptions, the adoption of the stock-based benefit plans will result in no additional shares under the treasury stock method for calculating earnings per share. There can be no assurance that the actual exercise price of the stock options will be equal to the $10.00 price per share. If a portion of the shares used to satisfy the exercise of options comes from authorized but unissued shares, our net income per share and stockholders’ equity per share would decrease. The issuance of authorized but unissued shares of common stock pursuant to the exercise of options under such plan would dilute stockholders’ ownership and voting interests by approximately 4.34%, 3.60%, 3.69% and 3.75% at the adjusted minimum, minimum, midpoint and maximum of the offering range, respectively.

(4)

Per share figures include publicly held shares of Columbia Financial common stock that will be exchanged for shares of Columbia Financial, Inc. common stock in the conversion. See “The Conversion and Offering — Share Exchange Ratio for Current Stockholders.” Per share figures also include shares issued to Northfield Bancorp stockholders who elect to receive Columbia Financial stock as merger consideration. Net income per share computations are determined by taking the number of shares assumed to be sold in the offering and the number of new shares assumed to be issued in exchange for publicly held shares of Columbia Financial and, in accordance with ASC 718-40, subtracting the employee stock ownership plan shares that have not been committed for release during the year. See note (1) above. The number of shares of common stock actually sold and the corresponding number of exchange shares may be more or less than the assumed amounts.

(5)

Per share figures include publicly held shares of Columbia Financial common stock that will be exchanged for shares of Columbia Financial, Inc. common stock in the conversion as well as shares issued to Northfield Bancorp stockholders who elect to receive Columbia Financial, Inc. stock as merger consideration. Stockholders’ equity per share calculations are based upon the sum of: (i) the number of shares assumed to be sold in the offering, and (ii) shares to be issued in exchange for publicly held shares of Columbia Financial at the adjusted minimum, minimum, midpoint and maximum of the offering range, respectively. The exchange shares reflect an exchange ratio of 1.8729, 1.8729, 2.2035, and 2.5340 at the adjusted minimum, minimum, midpoint and maximum of the offering range, respectively. The number of shares actually sold and the corresponding number of exchange shares may be more or less than the assumed amounts.

(6)

The foregoing tabular presentation assumes that Northfield Bancorp stockholders elect to receive 70% of the merger consideration in the form of Columbia Financial common stock. Assuming Northfield Bancorp stockholders elect to receive 100% of the merger consideration in the form of Columbia Financial common stock, the proforma price-to-earnings, price-to book value and price-to-tangible book value ratios would be as follows at the adjusted minimum, minimum, midpoint and maximum of the offering range:


	Adjusted Minimum			Minimum			Midpoint			Maximum
Offering price as a multiple of pro forma net income per share		23.81x			26.32x			27.78x			30.30x
Offering price as a percentage of pro forma equity per share		79.37	%		83.26	%		87.72	%		92.17	%
Offering price as a percentage of pro forma tangible equity per share		86.06	%		88.81	%		93.20	%		97.47	%

THE ACQUISITION OF NORTHFIELD BANCORP

General

On January 31, 2026, we entered into an agreement to acquire Northfield Bancorp, which is the holding company for Northfield Bank, a federal savings bank headquartered in Staten Island, New York. Northfield Bank provides a full range of deposit and loan products to area businesses and consumers. As of December 31, 2025, Northfield Bancorp had consolidated assets of $5.8 billion, deposits of $4.0 billion and stockholders’ equity of $690.1 million.

Reasons for the Acquisition

Following the acquisition of Northfield Bancorp, the resulting Columbia Bank will be a larger, more diversified, well-capitalized community bank with a management and operating structure that will draw from the business strategies currently being used at both Columbia Bank and Northfield Bank. On a pro forma basis at the maximum of the offering range, after giving effect to the acquisition of Northfield Bancorp, the combined entity would have had total assets of $18.0 billion and total deposits of $12.5 billion as of December 31, 2025. We believe that the proposed merger offers unique operating and strategic benefits, including that:

•

We expect the merger to meaningfully increase net income and return on assets;

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The merger leverages a portion of the capital raised in the offering;

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The transaction increases our market footprint, New Jersey deposit market share and branch network;

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The merger provides entry into the Staten Island and Brooklyn markets;

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The merger diversifies our loan portfolio;

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The transaction provides important customer facing revenue producers and back-office support;

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The transaction is projected to provide expense synergies; and

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Management expects to generate additional fee income by offering additional products and services to Northfield Bank’s customers.

Post-Acquisition Business Strategy

We believe that we will be well-positioned to pursue our key business strategies following the acquisition of Northfield Bancorp. Highlights of our business strategy are:

•

Increasing our earnings by growing our balance sheet with increased emphasis on commercial business lending and core deposits.

We intend to continue growing our balance sheet through organic growth of loans and deposits. We expect this growth to increase revenue at a faster rate than expenses, resulting in increased earnings.

We have a diversified loan portfolio, which includes commercial real estate and multifamily loans, residential mortgage loans, residential and commercial construction loans, commercial business loans and consumer loans, including home equity loans and advances. We expect that commercial business loan growth will outpace other types of lending as a result of the hiring of additional commercial lenders and business development officers to expand our commercial borrower base.

Management will focus on growing core deposits through new customer acquisition and by deepening existing customer relationships. These strategies are expected to enhance our net interest margin under the current rate environment. Excess liquidity generated by the capital raised in the offering will initially be invested in securities, and we expect to deploy a portion of these funds into loans over time.

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Employing a stockholder-focused management of capital.

Maintaining a strong capital base is critical to support our long-range business plan; however, we expect to have a high level of capital following completion of the merger and offering. Consequently, we intend to manage our capital position through asset growth, and the use of appropriate capital management tools, consistent with applicable regulations and policies and subject to market conditions. Under current federal regulations, subject to limited exceptions, we may not repurchase shares of our common stock during the first year following the completion of the offering.

Following the completion of the offering, our board of directors will have the authority to declare dividends on shares of our common stock and expects to pay dividends in the future, subject to statutory and regulatory requirements and other considerations.

•

Expanding our franchise through de novo branching, branch acquisitions and the possible acquisition of other financial institutions and/or financial services companies.

We believe there are branch expansion opportunities within our market area and adjacent markets, including other states, and we intend to grow our deposit base by adding branches to our branch network. In addition to deposit generation, our branch network also supports the generation of consumer and home equity loans and advances. While we are aware of the industry-wide branch consolidation trends, driven by lower transaction volumes, we believe that selectively expanding our network is necessary to attract new customers, fill in gaps in our existing footprint and enter adjacent markets. We believe that new smaller, more cost-efficient branch designs are appropriate for the expected transaction volumes.

Our growth strategy also includes the potential acquisition of other financial institutions. Since our initial minority offering, we have acquired four financial institutions, excluding the pending merger with Northfield. However, there is no guarantee that we will be successful in executing our acquisition strategy. While we continue to explore and evaluate acquisition opportunities, we currently have no understandings or agreements with respect to any branch acquisitions or acquisitions of other financial institutions and/or financial services companies.

•

Maintaining asset quality through the application of a prudent, disciplined approach to credit risk as part of an overall risk management program.

We employ a conservative, analytical approach to asset selection that has been tested across multiple business and interest rate cycles. This approach applies to both our investment portfolio, comprised primarily of liquid, low credit-risk, government agency-backed securities, and our loan portfolio. Our loan portfolio is subject to independent internal and external reviews, to validate adherence to policies and to identify and mitigate potential interest rate and credit risks. We utilize management information systems that provide regular insight into the level and direction of credit risk, across loan portfolio segments, including borrower- and industry-specific concentrations. We maintain limits on concentration risk, including limits on the ratio of commercial real estate and construction loan portfolios to capital. We have developed reporting, analytics and stress testing processes that we believe provide effective oversight at higher concentration levels.

We also employ pricing and risk management tools to ensure we are appropriately compensated for the risks inherent in our lending products and specific transactions. Our loan pricing model quantifies the credit and interest rate risks embedded in new loan originations and establishes target return thresholds.

We operate Risk Committees at both the management and board levels that oversee changes in the level and direction of risk. These committees review our Key Risk Indicators, which incorporate data from our Asset/Liability Committee, loan portfolio credit metrics, stress testing, cyber-risk and treasury risk (investment and funding) metrics.

•

Enhancing our technology infrastructure to broaden our product capabilities and improve product delivery and efficiency.

We have embraced many of the recent technological advancements in the banking industry, which we believe allow us to better leverage our employees by enabling them to focus on developing customer relationships, efficiently generating retail deposits, expanding the suite of products offered to customers, and competing more effectively as we grow. We continue to further enhance our digital delivery channels, both online and mobile, to deliver appealing products and services and to meet evolving customer expectations.

We also seek to implement tools that improve employee efficiency. We have deployed automated processes to eliminate certain manual tasks, enhancing both efficiency and accuracy. In addition, we are implementing artificial intelligence tools within our commercial loan underwriting process to reduce the time needed to research loan transactions and spread financial statements. We intend to evaluate additional artificial intelligence opportunities while maintaining a disciplined and responsible approach supported by appropriate governance, risk management, and data controls.

We expect continued investments in scalable technology capabilities that enhance competitive positioning, improve operational efficiency, strengthen risk management and resilience, and support long-term growth.

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Focusing on an enhanced customer experience and continued customer satisfaction.

Columbia Bank focuses on customer experience by closely monitoring multiple feedback channels, including customer surveys, call insights, complaints and support case volume. A dedicated Client Experience Team reviews this information regularly and works with business lines to address issues, improve processes, and maintain consistent service standards. Strategic investments are centered on expanding digital banking tools, strengthening the product set, and enhancing delivery channels to meet customer needs efficiently. Columbia Bank also continues to invest in experienced front-line professionals and modernized banking facilities to ensure strong service execution across all touchpoints. This disciplined approach supports high service quality, sustained customer satisfaction, and a strong competitive position in the market.

•

Increasing fee income through continued growth of fee-based activities.

We intend to focus on growing our title insurance and insurance businesses, expanding the scope of our wealth management services, and enhancing our treasury services in order to increase revenue generated from our fee-based businesses.

We currently offer title insurance services through our title insurance agency, property and casualty insurance through our insurance agency, and wealth management services through a third-party networking arrangement. To expand these offerings, we have pursued acquisitions in recent years, including the purchase of the Jeanne S. Frey Insurance Agency book of business, and we expect to continue pursuing acquisitions of fee-based businesses following the offering. We may also consider the acquisition of other fee-based businesses such as specialty lending companies. While we continue to explore and evaluate potential acquisition opportunities, we currently have no understandings or agreements with respect to any such acquisitions.

Columbia Bank currently plans to sell a portion of its available for sale investments, not expected to exceed $400 million of Columbia Bank’s lower-yielding mortgage-backed securities, during the third quarter of 2026 following the completion of the conversion and the acquisition of Northfield Bancorp. The sale of the securities, when combined with merger expenses, is currently expected to result in a net loss for the third quarter, the amount of which will not be ascertainable until the sale of the securities occurs. We do not anticipate that the sale of any such securities will have a material effect on our financial condition given the significant amount of new capital we will raise in connection with the conversion. In addition, the securities restructuring transaction will enable Columbia Bank to reinvest the proceeds from the sale into higher-yielding assets, which we believe will improve future earnings and interest-rate risk, and improve balance sheet flexibility in the future.

See “Business of Columbia Financial and Columbia Bank” and “Business of Northfield Bancorp and Northfield Bank” for a further discussion of our business strategy.

Management of the Combined Company

Following the completion of the merger, the board of directors of Columbia Financial, Inc. and Columbia Bank will consist of the nine directors of Columbia Financial, Inc. as of the effective time of the merger, as well as four members of Northfield Bancorp’s board of directors, including Steven M. Klein and three current members of Northfield Bancorp’s board of directors who will be determined prior to the closing of the offering and merger. At the close of the merger, the Board of Directors will be comprised of 13 directors.

Following the effective time of the merger, the executive management team of Columbia Financial, Inc. and Columbia Bank will continue in their current roles as executive officers of Columbia Financial, Inc. and Columbia Bank. In addition, at the effective time of the merger, Steven M. Klein, Chairman, President and Chief Executive Officer of Northfield Bancorp, will become Senior Executive Vice President and Chief Operating Officer of Columbia Financial, Inc. and Columbia Bank.

For information about our existing directors and executive officers, see “Management of Columbia Financial, Inc.”

Acquisition Details

Northfield Bancorp will merge into Columbia Financial, Inc. immediately following the completion of the second-step conversion. At the effective time of the merger, each outstanding share of Northfield Bancorp common stock will be converted into the right to receive either shares of Columbia Financial, Inc. common stock or cash, without interest, at the election of the holder, as follows: (i) if the final independent valuation is less than $2.3 billion, either 1.425 shares of Columbia Financial, Inc. common stock or $14.25 in cash; (ii) if the final independent valuation is equal to or greater than $2.3 billion and less than $2.6 billion, either 1.450 shares of Columbia Financial, Inc. common stock or $14.50 in cash, or (iii) if the final independent valuation is equal to or greater than $2.6 billion, 1.465 shares of Columbia Financial, Inc. common stock or $14.65 in cash. The “final independent valuation” is also sometimes referred to herein as the “appraised full conversion value.”

Each holder of record of shares of Northfield Bancorp common stock (other than holders that have exercised appraisal rights under Delaware law) will have the right to submit an election specifying:

•

the number of shares of Northfield Bancorp common stock owned by such holder with respect to which the holder desires to make an election for stock consideration (in which case the holder will be deemed to have made a stock election with respect to such shares and an election for cash consideration with respect to the balance, if any); or

•

the number of shares of Northfield Bancorp common stock owned by such holder with respect to which the holder desires to make an election for cash consideration (in which case the holder will be deemed to have made a cash election with respect to such shares and an election for stock consideration with respect to the balance, if any).

Under the terms of the merger agreement, no more than 30% of the outstanding shares of Northfield Bancorp common stock issued and outstanding as of the effective time of the merger may be converted into the cash consideration. The merger will only occur if the second-step conversion is completed.

Non-Electing Shares. Northfield Bancorp stockholders who make no election to receive cash or Columbia Financial, Inc. common stock in the merger or who make an invalid election will be deemed not to have made an election. Stockholders not making an election may be paid in cash, Columbia Financial, Inc. common stock or a mix of cash and shares of Columbia Financial, Inc. common stock depending on, and after giving effect to, the number of valid cash elections and stock elections that have been made by other Northfield Bancorp stockholders.

Election Limitations. The number of shares of Northfield Bancorp common stock that will be converted into the cash consideration may not exceed 30% of the outstanding shares of Northfield Bancorp common stock issued and outstanding at the time of the merger. Therefore, the cash and stock elections are subject to proration to preserve this requirement regarding the number of shares of Columbia Financial, Inc. common stock to be issued and the cash to be paid in the merger. Further, if counsel for Columbia Financial reasonably determines that the merger may not satisfy the continuity of interest requirements applicable to reorganizations under Section 368(a) of the Internal Revenue Code, Columbia Financial will reduce the number of shares of Northfield Bancorp common stock entitled to receive the cash consideration and correspondingly increase the number of shares of Northfield Bancorp common stock entitled to receive the stock consideration by the minimum amount necessary to enable the merger to satisfy such continuity of interest requirements. As a result, Northfield Bancorp stockholders may receive a mix of cash and stock.

Treasury Shares and Shares Held by Columbia Financial or Northfield Bancorp or Any of Their Subsidiaries. Any shares of Northfield Bancorp common stock owned immediately before the merger by Northfield Bancorp or Columbia Financial (other than shares held by either in a fiduciary or agency capacity or in satisfaction of prior debts) will be canceled and retired and will cease to exist, and no consideration will be delivered in exchange for those shares.

Adjustments to the Merger Consideration. If before the merger, the outstanding shares of Columbia Financial, Inc. common stock or Northfield common stock are changed into a different number of shares by reason of any reclassification, recapitalization or combination, stock split, reverse stock split, stock dividend or rights issued in respect of such stock, merger or consolidation, or any similar event occurs, the merger consideration will be proportionately adjusted to provide Northfield Bancorp stockholders the same economic effect as contemplated by the merger before the event causing the change in number of shares.

Northfield Bancorp Stock Options. At the effective time of the merger, each outstanding Northfield Bancorp stock option will be converted automatically into an option to purchase shares of Columbia Financial, Inc. common stock and will continue to be subject to the same terms and conditions as applied to the Northfield Bancorp stock option immediately prior to the effective time of the merger. The number of shares of Columbia Financial, Inc. common stock subject to each assumed Northfield Bancorp stock option will be equal to the number of shares of Northfield Bancorp common stock subject to the stock option immediately prior to the effective time of the merger, multiplied by the merger exchange ratio and rounded down to the nearest whole share. The per share exercise price of each assumed Northfield Bancorp stock option will also be adjusted by dividing the per share exercise price of the stock option by the merger exchange ratio, rounded up to the nearest cent.

Change in Final Independent Valuation. Notwithstanding any other provision of merger agreement, if the midpoint of the valuation range included in the final independent valuation decreases by 20% or more from the preliminary midpoint as of January 30, 2026, the date of announcement of the merger: (i) Columbia Financial may, in its sole discretion after consultation with its financial advisor, delay the conversion (provided, however, that such delayed conversion must close no later than January 31, 2027); or (ii) the parties will engage in good faith negotiations to adjust the amount of the merger consideration to be paid under the merger agreement, taking into account such decrease from the preliminary midpoint. If the parties cannot agree as to an adjustment to the merger consideration, either party can terminate the merger.

Conditions to Completion. Completion of the merger depends upon a number of conditions being satisfied or waived, including the following:

•

approval of the conversion and the merger by the stockholders of Columbia Financial, approval of the conversion by the members of Columbia Bank MHC, and approval of the merger by the stockholders of Northfield Bancorp;

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the authorization for listing on the Nasdaq of the shares of Columbia Financial, Inc. common stock that will be issued as merger consideration;

•

the receipt or provision of all non-governmental notices, consents or waivers by non-governmental third parties, except as would not reasonably be expected to have a material adverse effect on Northfield Bancorp, Columbia Financial or Columbia Financial, Inc.;

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the effectiveness of the Form S-4 registration statement and the absence of any stop order by the SEC suspending such effectiveness;

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the receipt of all required regulatory approvals, in each case without the imposition of any materially burdensome regulatory condition;

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no order, injunction or decree issued by any court or governmental entity or other legal restraint or prohibition preventing the completion of the merger or the bank merger;

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the deposit of cash and certificates representing sufficient shares of Columbia Financial, Inc. common stock sufficient to pay the merger consideration;

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the completion of the conversion;

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no event has occurred or circumstance has arisen that, individually or in the aggregate, has had or will reasonably be likely to have a material adverse effect on Northfield Bancorp or any of its subsidiaries;

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the accuracy of the representations and warranties of Columbia Financial, Inc. and Northfield Bancorp contained in the merger agreement, both as of the date of the agreement and as of the closing date, subject to the materiality standards provided for in the agreement;

•

the performance in all material respects by each of Columbia Financial, Inc. and Northfield Bancorp of their respective obligations, covenants and agreements required to be performed under the merger agreement; and

•

the receipt by each of the parties of an opinion of legal counsel that the merger will qualify as a “reorganization” within the meaning of Section 368(a) of the Code.

Any shares of Columbia Financial, Inc. common stock to be issued in connection with the merger will be issued immediately following the completion of the conversion.

We anticipate simultaneously completing the conversion, offering and merger in the third quarter of 2026, although no assurance can be given that we will be able to complete these transactions by that time.

Explanatory Note Regarding the Merger Agreement

Any summary in this prospectus of some of the terms of the merger agreement between Columbia Financial and Northfield Bancorp are included to provide you with general information regarding the terms of the merger agreement. Factual disclosures about Columbia Financial and Northfield Bancorp contained in this prospectus or in the public reports of Columbia Financial or Northfield Bancorp filed with the SEC may supplement, update or modify the factual disclosures about Columbia Financial and Northfield Bancorp contained in the merger agreement. The merger agreement contains representations and warranties by Columbia Financial and Northfield Bancorp, respectively, made solely for the benefit of the other. The representations, warranties and covenants made in the merger agreement by Columbia Financial and Northfield Bancorp were qualified and subject to important limitations agreed to by Columbia Financial and Northfield Bancorp in connection with negotiating the terms of the merger agreement. In particular, the representations and warranties were negotiated with the principal purpose of establishing circumstances in which a party to the merger agreement may have the right not to consummate the merger if the representations and warranties of the other party prove to be untrue due to a change in circumstance or otherwise, and allocating risk between the parties to the merger agreement, rather than establishing matters as facts. The representations and warranties also may be subject to a contractual standard of materiality different from that generally applicable to shareholders and reports and documents filed with the SEC, and some were qualified by the matters contained in the confidential disclosure schedules that Columbia Financial and Northfield Bancorp each delivered in connection with the merger agreement. Moreover, information concerning the subject matter of the representations and warranties, which do not purport to be accurate as of the date of this prospectus, may have changed since the date of the merger agreement. Accordingly, the representations and warranties in the merger agreement should not be relied on by any persons as characterizations of the actual state of facts about Columbia Financial and Northfield Bancorp at the time they were made, as of the date of this prospectus, or otherwise.

BUSINESS OF COLUMBIA FINANCIAL AND COLUMBIA BANK

General

Columbia Financial is a Delaware corporation that was organized in 1997 in connection with the mutual holding company reorganization of Columbia Bank. Columbia Financial is the holding company of Columbia Bank, which is a federal savings bank. Columbia Bank MHC was also organized in March 1997 under the laws of the United States. In connection with the reorganization, Columbia Financial became the wholly-owned subsidiary of Columbia Bank MHC.

Columbia Bank was founded in 1927. Columbia Bank has elected and has received regulatory approval to operate as a “covered savings association” pursuant to the Home Owners’ Loan Act, as amended, and the regulations of the OCC promulgated thereunder. A covered savings association generally has the same rights and privileges as a national bank, and is subject to the same duties, restrictions, penalties, liabilities, conditions, and limitations that would apply to a national bank. Management believes that the key benefits of Columbia Bank’s election to operate as a covered savings association include the elimination of the requirement to meet the qualified thrift lender test and that Columbia Bank is no longer subject to the limits on an aggregate amount of commercial loans that are applicable to savings associations.

We serve the financial needs of our depositors and the local community as a community-minded, customer service-focused institutions. We offer traditional financial services to businesses and consumers in our market areas. We attract deposits from the general public and use those funds to originate a variety of loans, including multifamily and commercial real estate loans, commercial business loans, one-to-four family real estate loans, construction loans, home equity loans and advances, and other consumer loans. We offer title insurance through our wholly-owned subsidiary, First Jersey Title Services, Inc. In addition, Columbia Insurance Services, Inc., a wholly-owned subsidiary of Columbia Bank, is a full-service insurance agency that offers a broad range of insurance products, including personal and business lines of insurance, to our customers and primarily New Jersey residents. Wealth management services are also offered through a third-party relationship.

Throughout this prospectus, references to “we,” “us” or “our” refer to Columbia Financial and Columbia Bank collectively.

Acquisition History

Atlantic Stewardship Bank. On November 1, 2019, Columbia Financial completed its acquisition of Stewardship Financial Corporation (“Stewardship Financial”) and Atlantic Stewardship Bank, the wholly-owned subsidiary of Stewardship Financial. At the effective time of the merger, Stewardship Financial merged with and into Columbia Financial in a series of transactions, with Columbia Financial as the surviving entity, and immediately thereafter, Atlantic Stewardship Bank merged with and into Columbia Bank, with Columbia Bank as the surviving institution. In addition, at the effective time of the merger, each outstanding share of Stewardship Financial common stock was converted into the right to receive from Columbia Financial a cash payment equal to $15.75. The total consideration paid was $136.3 million.

Roselle Bank. On April 1, 2020, Columbia Financial completed its acquisition of RSB Bancorp, MHC, RSB Bancorp, Inc. and Roselle Bank (collectively, the “Roselle Entities”). At the effective time of the merger, (i) RSB Bancorp, MHC merged with and into Columbia Bank MHC, with Columbia Bank MHC as the surviving entity, (ii) RSB Bancorp, Inc. merged with and into Columbia Financial, with Columbia Financial as the surviving entity; and (iii) Roselle Bank merged with and into Columbia Bank, with Columbia Bank as the surviving institution. In addition, at the effective time of the merger, depositors of Roselle Bank became depositors of Columbia Bank and were afforded the same rights and privileges in Columbia Bank MHC as if their accounts had been established at Columbia Bank on the date established at Roselle Bank. At the effective time of the merger, Columbia Financial also issued 4,759,048 additional shares of its common stock to Columbia Bank MHC, representing an amount equal to the fair value of the Roselle Entities, as determined by an independent appraiser.

Freehold Bank. On December 1, 2021, Columbia Financial completed its acquisition of Freehold Bancorp, MHC, Freehold Bancorp, Inc. and Freehold Bank (collectively, the “Freehold Entities” or “Freehold”). At the effective time of the

merger, (i) Freehold Bancorp, MHC was merged with and into Columbia Bank MHC, with Columbia Bank MHC as the surviving entity, and (ii) Freehold Bancorp, Inc. was merged with and into Columbia Financial, with Columbia Financial as the surviving entity. To facilitate the transaction, Freehold Bank converted from a New Jersey chartered savings bank to a federally chartered savings bank. At the effective time of the merger, Columbia Financial also issued 2,591,007 additional shares of its common stock to Columbia Bank MHC, representing an amount equal to the fair value of the Freehold Entities, as determined by an independent appraiser. Following the acquisition of the Freehold Entities, Freehold Bank was maintained as a separate banking subsidiary of Columbia Financial until October 5, 2024, when it was merged with and into Columbia Bank. In addition, at the effective time of the merger of the two banks, depositors of Freehold Bank became depositors of Columbia Bank and were afforded the same rights and privileges in Columbia Bank MHC as if their accounts had been established at Columbia Bank on the date established at Freehold Bank.

RSI Bank. On May 1, 2022, Columbia Financial completed its acquisition of RSI Bancorp, M.H.C., RSI Bancorp, Inc. and RSI Bank (collectively, the “RSI Entities” or “RSI”). At the effective time of the merger, (i) RSI Bancorp, M.H.C. merged with and into Columbia Bank MHC, with Columbia Bank MHC as the surviving entity, (ii) RSI Bancorp, Inc. merged with and into Columbia Financial, with Columbia Financial as the surviving entity; and (iii) RSI Bank merged with and into Columbia Bank, with Columbia Bank as the surviving institution. In addition, at the effective time of the merger, depositors of RSI Bank became depositors of Columbia Bank and were afforded the same rights and privileges in Columbia Bank MHC as if their accounts had been established at Columbia Bank on the date established at RSI Bank. At the effective time of the merger, Columbia Financial also issued 6,086,314 shares of its common stock to Columbia Bank MHC, representing an amount equal to the fair value of the RSI Entities as determined by an independent appraiser.

Market Area

We are headquartered in Fair Lawn, New Jersey. As of December 31, 2025, Columbia Bank operated 71 full-service banking offices in 12 of New Jersey’s 21 counties. In addition, (i) First Jersey Title Services, Inc., a wholly-owned subsidiary of Columbia Bank, operates in one of Columbia Bank’s offices in Fair Lawn, New Jersey and (ii) Columbia Insurance Services, Inc., a wholly-owned subsidiary of Columbia Bank, operates in one of Columbia Bank’s offices in Rahway, New Jersey. We periodically evaluate our network of banking offices to optimize the penetration in our market area. Our business strategy currently includes opening new branches in and around our market area, which may include neighboring states. In March 2026, our branch located in High Bridge, New Jersey was closed and as of the date of this prospectus, Columbia Bank operates 70 full-service banking offices in eleven of New Jersey’s 21 counties.

We consider our market area to be the State of New Jersey and the suburbs surrounding both the New York City and Philadelphia metropolitan areas. This area has historically benefited from having a large number of corporate headquarters and a concentration of financial services-related industries located within it. The area also benefits from having a well-educated employment base and a large number of diverse industrial, service, retail and high technology businesses. Other employment is provided by a variety of wholesale trade, manufacturing, federal, state and local governments, hospitals and utilities.

According to S&P Global projections based on 2020 U.S. Census Data, the population of our twelve-county primary market area totaled approximately 8.4 million and the total population for the entire state of New Jersey was 9.6 million. The population in our 12-county market area has increased by 3.33% from 2020 to 2026. According to S&P Global, the weighted average projected median household income for 2026 for the 12 New Jersey counties that we operate in was $118,137. By contrast, the national projected median household income for 2026 is $86,867 and the State of New Jersey projected median income is $108,801. The unemployment rate, not seasonally adjusted, for the State of New Jersey was 4.8% in December 2023, 4.6% in December 2024, and 5.4% in December 2025, compared to the national unemployment rate of 3.7% in December 2023, 4.1% in December 2024, and 4.4% in December 2025.

Following completion of the acquisition of Northfield Bancorp, our market area will expand to include additional branches in central New Jersey and branches in Staten Island, Brooklyn and other areas of New York City. We anticipate the post-acquisition, Columbia Bank will operate over 100 branches throughout 14 counties in the State of New Jersey and in Staten Island and Brooklyn in the State of New York.

Competition

We face significant competition in attracting deposits. Many of the nation’s largest financial institutions operate in our market area. Our most direct competition for deposits has historically come from the many banks, thrift institutions and credit unions operating in our market area and from other financial service companies such as brokerage firms and insurance companies. We also face competition for investors’ funds from money market funds, mutual funds and other corporate and government securities.

Our competition for loans comes primarily from the competitors referenced above and from other financial service providers, such as mortgage companies and mortgage brokers. Competition for loans also comes from the increasing number of non-depository financial service companies participating in the mortgage market, such as insurance companies, securities companies, financial technology companies and specialty finance firms, along with federal agencies.

We expect competition to remain intense in the future as a result of legislative, regulatory and technological changes and the continuing trend of consolidation in the financial services industry. Technological advances, for example, have lowered barriers to entry, allowed banks to expand their geographic reach by providing services over the internet and made it possible for non-depository institutions, including financial technology companies, to offer products and services that traditionally have been provided by banks. Competition for deposits and the origination of loans could limit our growth in the future.

Lending Activities

Through our banking subsidiary, Columbia Bank, we offer a variety of loans, including commercial, residential and consumer loans. Our commercial loan portfolio includes multifamily and commercial real estate loans, commercial business loans and construction loans. Our residential loan portfolio includes one-to-four family residential real estate loans and one-to-four family residential construction loans. Our consumer loan portfolio primarily includes home equity loans and advances, and to a lesser extent automobile, personal, unsecured and overdraft lines of credit.

We intend to continue to emphasize commercial lending. In the past six years, we have completed our acquisitions of Stewardship Financial, Roselle Bank, Freehold Bank and RSI Bank, and we have continued to invest in our lending staff, technology and processes to position us for continued growth. Specifically, in the past three years, we have hired additional lenders with significant experience in our market area to expand our commercial real estate and commercial business lending efforts, including an asset-based and equipment finance lending team with long-term existing relationships. In addition, we will continue to offer competitive pricing for our one-to-four family loan products and continue to market these products in New Jersey, New York and Pennsylvania.

Multifamily and Commercial Real Estate Loans. We originate mortgage loans for the acquisition and refinancing of multifamily properties and nonresidential real estate. At December 31, 2025, multifamily and commercial real estate loans totaled $4.2 billion, or 50.9% of our total loan portfolio. Of this amount, $3.4 billion of loans were used for the purchase, financing and/or refinancing of commercial real estate and the financing of income-producing real estate. The majority of these loans are generally non-owner-occupied properties in which 50% or more of the primary source of repayment is derived from rental income from unaffiliated third parties. Our multifamily loans include loans primarily to finance apartment buildings located in the State of New Jersey, and to a lesser extent, in New York and Pennsylvania. Our commercial real estate loans include loans secured by retail shopping centers, industrial, warehouses, non-medical office buildings, medical office buildings, hotels, assisted-living facilities and similar commercial properties. At December 31, 2025, Columbia Bank had approximately $846,000 of New York multifamily loans that have some form of rent stabilization or rent control.

We offer both fixed and adjustable rate multifamily and commercial real estate loans. We originate these loans generally for terms of up to ten years and with payments generally based on an amortization schedule of up to 30 years for multifamily and industrial commercial real estate properties, and up to 25 years for commercial properties. Our adjustable rate loans are typically fixed from three to ten years, with a component of the adjustable rate loan portfolio indexed to a monthly market based index.

The following tables provide additional details regarding our multifamily and commercial real estate loan portfolio as of December 31, 2025:


	At December 31, 2025
	Balance		% of Gross Loans			Weighted Average Loan to Value Ratio			Weighted Average Debt Service Coverage
	(Dollars in thousands)
Multifamily real estate	$	1,677,613		21.0	%		59.0	%		1.59
Owner occupied commercial real estate		667,239		8.4			59.5			2.56
Investor owned commercial real estate:
Retail/shopping centers		541,648		6.8			55.1			1.57
Mixed use		298,993		3.7			61.1			1.52
Industrial/warehouse		433,749		5.4			53.4			1.66
Non-medical office		172,614		2.2			51.8			1.88
Medical office		97,556		1.2			60.2			1.49
Single purpose		62,283		0.8			62.1			1.37
Other		239,148		3.0			51.8			2.14

Total	$	1,846,021

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Accelerated filer

Non-accelerated filer

Smaller reporting company

Emerging growth company

Columbia Financial, Inc./MD/ S-1/A