Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * BERKES OTTO 2. Issuer Name and Ticker or Trading Symbol INTEGRAL AD SCIENCE HOLDING CORP. [IAS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O INTEGRAL AD SCIENCE HOLDING CORP., 12 E. 49TH STREET, 20TH FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 12/23/2025 (Street) NEW YORK, NY 10017 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock, $0.001 par value 12/23/2025 D(1)(2) 80,601 D $10.3 0 D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
BERKES OTTO C/O INTEGRAL AD SCIENCE HOLDING CORP. 12 E. 49TH STREET, 20TH FLOOR NEW YORK, NY 10017	X

Signatures

/s/ Yossi Almani, by Power of Attorney		12/23/2025
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Pursuant to the Agreement and Plan of Merger, dated as of September 24, 2025 (the "Merger Agreement"), by and among the Issuer, Igloo Group Parent, Inc. ("Parent") and Igloo Group Acquisition Company, Inc. ("Merger Sub"), Merger Sub merged with and into the Issuer (the "Merger"), with the Issuer surviving as a wholly owned subsidiary of Parent. At the effective time of the Merger (the "Effective Time"), each issued and outstanding share of the Issuer's common stock, par value $0.001 per share ("Common Stock"), owned by the reporting person immediately prior to the Effective Time was automatically cancelled, extinguished and converted into the right to receive $10.30 per share in cash, without interest thereon (the "Per Share Price").
(2)	The shares of Common Stock reported as disposed by the reporting person include 17,637 unvested restricted stock units ("Company RSUs") which were, at or immediately prior the Effective Time, fully vested, cancelled and converted into the right to receive, without interest, an amount in cash equal to the product of (i) the Per Share Price and (ii) the total number of shares of Common Stock subject to such Company RSUs.

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