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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(Print or Type Responses)

1. Name and Address of Reporting Person * Utzschneider Lisa 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 __X__ Officer (give title below) _____ Other (specify below) Chief Executive Officer (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) 411,985(2) 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
Market Stock Units	(3)	12/23/2025		M			55,567(4)(5)(6)	(3)	(3)	Common Stock, $0.001 par value	55,567	$ 0	0	D
Market Stock Units	(3)	12/23/2025		M			157,674(4)(5)(6)	(3)	(3)	Common Stock, $0.001 par value	157,674	$ 0	0	D
Market Stock Units	(3)	12/23/2025		M			367,222(4)(5)(6)	(3)	(3)	Common Stock, $0.001 par value	367,222	$ 0	0	D
Market Stock Units	(3)	12/23/2025		M			975,238(4)(5)(6)	(3)	(3)	Common Stock, $0.001 par value	975,238	$ 0	0	D
Options (Right to Buy)	$6.17	12/23/2025		D			2,051,991	(7)	01/07/2029	Common Stock, $0.001 par value	2,051,991	$4.13	0	D

Reporting Owners

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

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)	Reflects a reduction in the total shares beneficially owned due to an administrative error in the reporting person's Form 4 filed on January 8, 2025 and subsequent forms, which reported fewer shares sold than required.
(3)	Upon the terms and subject to the conditions set forth in the Merger Agreement, the number of market stock units ("Company MSUs") reported was calculated based on a payout factor applicable to such Company MSUs determined based on the Per Share Price.
(4)	Upon the terms and subject to the conditions set forth in the Merger Agreement, fifty percent of the Company MSUs reported were, at or immediately prior to the Effective Time, automatically cancelled and converted into the right to receive an amount in cash (without interest and subject to applicable withholding taxes) equal to the product of (i) the Per Share Price and (ii) the total number of shares of Common Stock subject to such Company MSU as of immediately prior to the Effective Time (the "Converted Cash Awards"). The Converted Cash Awards will, subject to the reporting person's continued service through the applicable vesting dates, vest and be payable at the time when the Company MSUs for which the Converted Cash Awards were exchanged would have vested pursuant to the terms thereof.
(5)	Upon the terms and subject to the conditions set forth in the Merger Agreement, fifty percent of the Company MSUs reported were, at or immediately prior to the Effective Time, automatically cancelled and converted into a restricted limited partnership unit award with respect to an indirect parent entity of Parent (the "Replacement Company MSU Awards") with the number of units covered by such Replacement Company MSU Award to be equal to the quotient of (i) the product of (A) the Per Share Price and (B) the total number of shares of Company Common Stock subject to such Company MSU as of immediately prior to the Effective Time,
(6)	(Continued from Footnote 5) and (ii) the fair market value of such unit as of the Effective Time (based on the same price per unit paid to acquire equity in such entity in connection with the transactions contemplated by the Merger Agreement). The Replacement Company MSU Awards will, subject to the reporting person's continued service through the applicable vesting dates, vest and be settled at the time when the Company MSUs for which the Replacement Company MSU Awards were exchanged would have vested pursuant to the terms thereof.
(7)	Pursuant to the Merger Agreement, this stock option was, at or immediately prior to the Effective Time, cancelled and converted into the right to receive an amount in cash (without interest and subject to applicable withholding taxes) equal to the product of (i) the total number of shares of Common Stock subject to such option as of immediately prior to the Effective Time and (ii) the excess, if any, of the Per Share Price over the exercise price of such option.

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