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): September 24, 2025

INTEGRAL AD SCIENCE HOLDING CORP.

(Exact name of registrant as specified in its charter)

Delaware

001-40557

83-0731995

(State or other jurisdiction

of incorporation)

(Commission

File Number)

(IRS Employer
Identification No.)

12 E 49th Street, 20th Floor

New York, NY

10017

(Address of principal executive offices)

(Zip Code)

Registrant’s telephone number, including area code: 646 278-4871

Not Applicable

(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:

☐	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, par value $0.001	IAS	The Nasdaq Stock Market LLC (Nasdaq Global Select Market)

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

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.

On September 24, 2025, Integral Ad Science Holding Corp., a Delaware corporation (the “Company”), entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Igloo Group Parent, Inc., a Delaware corporation (“Parent”), and Igloo Group Acquisition Company, Inc., a Delaware corporation and a wholly owned subsidiary of Parent (“Merger Sub”). Parent and Merger Sub are affiliates of investment funds managed by Novacap Management Inc. (“Novacap”). Pursuant to the Merger Agreement, Merger Sub will be merged with and into the Company (the “Merger”), with the Company surviving as a wholly owned subsidiary of Parent.

On September 24, 2025, the Company and Parent issued a joint press release announcing the execution of the Merger Agreement. A copy of the press release is furnished herewith as Exhibit 99.1 and is incorporated by reference herein. The information required to be reported on a Current Report on Form 8-K with respect to the Merger Agreement will be filed by the Company in a separate Current Report on Form 8-K.

Cautionary Statement Regarding Forward-Looking Statements

This Current Report on Form 8-K, and the Company’s other filings, press releases and statements made in connection herewith may contain “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, each as amended, including statements regarding the benefits of the proposed acquisition of the Company and the associated integration plans, expected synergies and capital expenditure commitments, anticipated future operating performance and results of the Company, the expected management and governance of the Company following the acquisition, expected timing of the closing of the Merger and the other transactions contemplated by the Merger Agreement, and any other statements regarding the Company’s future expectations, beliefs, plans, objectives, financial condition, assumptions or future events or performance that are not historical facts. These forward-looking statements are based on management’s beliefs and assumptions and on information currently available to management. Forward-looking statements include all statements that are not historical facts and may be identified by terms such as “aim,” “anticipate,” “believe,” “can,” “could,” “seek,” “should,” “feel,” “expect,” “will,” “would,” “plan,” “project,” “intend,” “estimate,” “continue,” “may,” or similar expressions and the negatives of those terms. Forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. Factors that could cause or contribute to such differences include, but are not limited to, (i) the risk that the Merger may not be completed in a timely manner or at all, which may adversely affect the Company’s business and the price of the Company’s common stock, (ii) the timing to consummate the Merger, or the occurrence of any event, change, or other circumstances that could give rise to the termination of the Merger Agreement, including circumstances requiring a party to pay the other party a termination fee pursuant to the Merger Agreement, (iii) the failure to satisfy the conditions to the consummation of the Merger, and the other transactions contemplated thereby, (iv) the risk that a governmental or regulatory approval that may be required for the Merger is not obtained or is obtained subject to conditions that are not anticipated, (v) the effect of the announcement or pendency of the Merger on the Company’s business relationships, operating results and business generally, (vi) certain restrictions during the pendency of the Merger that may impact the Company’s ability to pursue certain business opportunities or strategic transactions, (vii) risks that the Merger disrupts current plans and operations, (viii) risks related to diverting management’s attention from the Company’s ongoing business operations, (ix) the outcome of any legal proceedings that may be instituted against the parties to the Merger Agreement or their respective directors, managers or officers, including the effects of any outcomes related thereto, (x) the Company’s ability to retain, hire and integrate skilled personnel, including the Company’s senior management team, and maintain relationships with key business partners and customers, and others with whom it does business, in light of the Merger, (xi) unexpected costs, charges or expenses resulting from the Merger, (xii) the impact of adverse general and industry-specific economic and market conditions, (xiii) risks related to the Company’s financial position and results of operations, (xiv) risks that the benefits of the Merger are not realized when and as expected, (xv) the impact of inflation and global conflicts, including ongoing trade disputes between the United States and other countries, and (xvi) other factors described under the heading “Risk Factors” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024, the Company’s subsequent Quarterly Reports on Form 10-Q, and in other reports and filings made or to be made by the Company with the U.S. Securities and Exchange Commission (the “SEC”). The Company cautions you that the important factors referenced above may not contain all of the factors that are important to you. In addition, the

Company cannot assure you that the Company will realize the results or developments expected or anticipated or, even if substantially realized, that they will result in the consequences or affect the Company or the Company’s operations in the way the Company expects. The forward-looking statements included in this Current Report on Form 8-K are made only as of the date hereof. Except as required by applicable law or regulation, the Company does not undertake to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Additional Information and Where to Find It

This Current Report on Form 8-K is being made in respect of the proposed transaction involving the Company and Novacap. The Company will prepare an information statement for its stockholders, containing the information with respect to the proposed merger specified in Schedule 14C promulgated under the Exchange Act, and describing the proposed transaction. When completed, a definitive information statement will be mailed to the Company’s stockholders. This press release is not a substitute for the information statement, or any other document, that the Company may file with the SEC or send to its stockholders in connection with the proposed transaction.

THE COMPANY’S STOCKHOLDERS ARE URGED TO CAREFULLY READ THE INFORMATION STATEMENT REGARDING THE PROPOSED TRANSACTION AND ANY OTHER RELEVANT DOCUMENTS IN THEIR ENTIRETY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION.

The Company’s stockholders may obtain free copies of the documents the Company files with the SEC from the SEC’s website at www.sec.gov or through the Investor Relations page of the Company’s website at https://investors.integralads.com or by contacting the Company’s Investor Relations by e-mail at ir@integralads.com.

No Offer or Solicitation

No person has commenced soliciting proxies in connection with the proposed transaction referenced in this Current Report on Form 8-K, and this Current Report on Form 8-K is neither an offer to purchase nor a solicitation of an offer to sell securities.

Item 9.01.

Financial Statements and Exhibits.

(d) Exhibits.


Exhibit No.		Description of Exhibit

99.1		Press Release, dated September 24, 2025.

104		Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

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.


	INTEGRAL AD SCIENCE HOLDING CORP.

Date: September 24, 2025
	By:	/s/ Alpana Wegner
	Name:	Alpana Wegner
	Title:	Chief Financial Officer (Principal Financial Officer)

INTEGRAL AD SCIENCE HOLDING CORP. 8-K