United States

Securities And Exchange Commission
Washington, D.C. 20549

FORM 8-K

Current Report

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): January 2129, 2026

(Exact name of registrant as specified in its charter)


Delaware	000-10537	36-3143493
(State or other jurisdiction of incorporation)	(Commission File Number)	(I.R.S. Employer Identification No.)

37 South River Street
Aurora, Illinois 60507
(Address of principal executive offices) (Zip code)

(630) 892-0202
(Registrant’s telephone number, including area code)

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:


Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock	OSBC	The Nasdaq Stock Market

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 under the Securities Act (17 CFR 230.405) or Rule 12b-2 under the Exchange Act (17 CFR 240.12b-2).

Emerging growth company ☐

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 13(a) of the Exchange Act. ☐

Item 8.01

Other Events.

~~Item~~The 2Board of Directors of Old Second Bancorp, Inc.02 ~~Results~~(the “Company”) has authorized the repurchase of ~~Operations~~up to $43.9 million of shares of the Company’s common stock (the “Repurchase Program”). On January 27, 2026, the Company received a letter from the Federal Reserve Bank of Chicago (the “Federal Reserve”) dated January 8, 2026, indicating its nonobjection to the Repurchase Program. Repurchases by the Company under the Repurchase Program may be made from time to time through open market purchases, trading plans established in accordance with U.S. Securities and ~~Financial~~Exchange ~~Condition~~Commission rules, privately negotiated transactions, or by other means.

OnThe ~~January~~actual 21means and timing of any repurchases, ~~2026~~quantity of purchased shares and prices will be, ~~Old~~subject ~~Second~~to ~~Bancorp~~certain limitations, ~~Inc.~~at (the “discretion of management and will depend on a number of factors, including, without limitation, market prices of the Company’s”) ~~issued~~common astock, ~~press~~general ~~release~~market ~~announcing~~and ~~its~~economic ~~financial~~conditions, ~~results~~and ~~for~~applicable legal and regulatory requirements. Repurchases under the ~~fourth~~Repurchase ~~quarter~~Program ~~ended~~may ~~December~~be 31initiated, ~~2025~~ discontinued, ~~along~~suspended ~~with~~or ~~certain~~restarted ~~other~~at ~~financial~~any ~~information.~~time; ~~Copies~~provided, ofthat repurchases under the ~~Company’s~~Repurchase ~~press~~Program ~~release~~after ~~and~~December ~~loan~~31, ~~portfolio~~2026 ~~disclosures~~would ~~are~~require ~~attached~~Federal asReserve ~~Exhibits~~non-objection 99or approval.1 ~~and~~The ~~99.2,~~Company ~~respectively~~is not obligated to repurchase any shares under the Repurchase Program.

~~Item 9.01 Financial Statements and Exhibits~~Signature

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.


Exhibit No.		Description
99.1		Press Release of Old Second Bancorp, Inc. dated January 21, 2026

99.2		Loan Portfolio Disclosures for Old Second Bancorp, Inc. dated December 31, 2025

104		Cover Page Interactive Data File (the cover page XBRL tags are embedded within the Inline XBRL document)


	OLD SECOND BANCORP, INC.


Dated: January 29, 2026	By:	/s/ Bradley S. Adams
		Bradley S. Adams
		Executive Vice President,
		Chief Operating Officer, and
		Chief Financial Officer

Signature

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.


	OLD SECOND BANCORP, INC.


Dated: January 21, 2026	By:	/s/ Bradley S. Adams
		Bradley S. Adams
		Executive Vice President,
		Chief Operating Officer and
		Chief Financial Officer

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