<SEC-DOCUMENT>0001395942-18-000015.txt : 20180208
<SEC-HEADER>0001395942-18-000015.hdr.sgml : 20180208
<ACCEPTANCE-DATETIME>20180208205740
ACCESSION NUMBER:		0001395942-18-000015
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180206
FILED AS OF DATE:		20180208
DATE AS OF CHANGE:		20180208

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Fisher Thomas J
		CENTRAL INDEX KEY:			0001597236

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34568
		FILM NUMBER:		18587404

	MAIL ADDRESS:	
		STREET 1:		7601 INTERACTIE WAY
		CITY:			INDIANAPOLIS
		STATE:			IN
		ZIP:			46278

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			KAR Auction Services, Inc.
		CENTRAL INDEX KEY:			0001395942
		STANDARD INDUSTRIAL CLASSIFICATION:	RETAIL-AUTO DEALERS & GASOLINE STATIONS [5500]
		IRS NUMBER:				208744739
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		13085 HAMILTON CROSSING BOULEVARD
		CITY:			CARMEL
		STATE:			IN
		ZIP:			46032
		BUSINESS PHONE:		(800) 923-3725

	MAIL ADDRESS:	
		STREET 1:		13085 HAMILTON CROSSING BOULEVARD
		CITY:			CARMEL
		STATE:			IN
		ZIP:			46032

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	KAR Holdings, Inc.
		DATE OF NAME CHANGE:	20070409
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_151814144572929.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-02-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001395942</issuerCik>
        <issuerName>KAR Auction Services, Inc.</issuerName>
        <issuerTradingSymbol>KAR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001597236</rptOwnerCik>
            <rptOwnerName>Fisher Thomas J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>13085 HAMILTON CROSSING BLVD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CARMEL</rptOwnerCity>
            <rptOwnerState>IN</rptOwnerState>
            <rptOwnerZipCode>46032</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP, Chief Information Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2018-02-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1780</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1780.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1780</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit is convertible into a share of common stock on a 1-for-1 basis.</footnote>
        <footnote id="F2">The compensation committee certified on February 6, 2018 that the Company achieved the 2017 net income performance goal for the restricted stock unit awards granted in 2017 under the KAR Auction Services, Inc. 2009 Omnibus Stock and Incentive Plan. These restricted stock units remain subject to a time-vesting requirement and are scheduled to vest and settle in common stock as follows: one-third of these restricted stock units vest on May 12, 2018, one-third of these restricted stock units vest on May 12, 2019 and the remaining one-third of these restricted stock units vest on May 12, 2020, assuming continued employment through the applicable vesting date.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Rebecca C. Polak, as Attorney-in-Fact</signatureName>
        <signatureDate>2018-02-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
