<SEC-DOCUMENT>0001842718-25-000091.txt : 20250805
<SEC-HEADER>0001842718-25-000091.hdr.sgml : 20250805
<ACCEPTANCE-DATETIME>20250805172629
ACCESSION NUMBER:		0001842718-25-000091
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250802
FILED AS OF DATE:		20250805
DATE AS OF CHANGE:		20250805

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Utzschneider Lisa
		CENTRAL INDEX KEY:			0001651659
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-40557
		FILM NUMBER:		251186280

	MAIL ADDRESS:	
		STREET 1:		C/O YAHOO! INC.
		STREET 2:		701 FIRST AVENUE
		CITY:			SUNNYVALE
		STATE:			CA
		ZIP:			94089

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			INTEGRAL AD SCIENCE HOLDING CORP.
		CENTRAL INDEX KEY:			0001842718
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMPUTER PROGRAMMING, DATA PROCESSING, ETC. [7370]
		ORGANIZATION NAME:           	06 Technology
		EIN:				830731995
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		12 EAST 49TH STREET
		STREET 2:		20TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
		BUSINESS PHONE:		(646) 278-4871

	MAIL ADDRESS:	
		STREET 1:		12 EAST 49TH STREET
		STREET 2:		20TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	INTEGRAL AD SCIENCE HOLDING LLC
		DATE OF NAME CHANGE:	20210301

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	KAVACHA TOPCO, LLC
		DATE OF NAME CHANGE:	20210127
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1754429185.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-08-02</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001842718</issuerCik>
        <issuerName>INTEGRAL AD SCIENCE HOLDING CORP.</issuerName>
        <issuerTradingSymbol>IAS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001651659</rptOwnerCik>
            <rptOwnerName>Utzschneider Lisa</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O INTEGRAL AD SCIENCE HOLDING CORP.</rptOwnerStreet1>
            <rptOwnerStreet2>12 E 49TH STREET, 20TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, $0.001 par value</value>
            </securityTitle>
            <transactionDate>
                <value>2025-08-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>19448</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>390479</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Market Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2025-08-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>19448</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock, $0.001 par value</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>19448</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>187541</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares of common stock earned upon the vesting of market stock units granted on June 17, 2022.</footnote>
        <footnote id="F2">The number of market stock units reported represents the maximum possible number of shares that are eligible for vesting, which is 225% of the number of shares that would be earned at target. The minimum payout factor that must be achieved to earn any payout is 60%. The actual number of shares that will vest on each vesting date will be determined by comparing the price of common stock on the applicable vesting date to the price of common stock on April 29, 2022 (i.e., number of vested shares is equal to (i) the number of shares at target payout multiplied by (ii) (a) the average price of common stock for the 10 trading days immediately preceding the applicable vesting date divided by (b) the closing stock price on April 29, 2022).</footnote>
        <footnote id="F3">The market stock units vest 25% on May 2, 2023 and in equal installments every three months thereafter over a three year period, subject to continued employment.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Yossi Almani, by Power of Attorney</signatureName>
        <signatureDate>2025-08-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
