<SEC-DOCUMENT>0001214659-25-015026.txt : 20251016
<SEC-HEADER>0001214659-25-015026.hdr.sgml : 20251016
<ACCEPTANCE-DATETIME>20251016165735
ACCESSION NUMBER:		0001214659-25-015026
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20251014
FILED AS OF DATE:		20251016
DATE AS OF CHANGE:		20251016

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LANSING WILLIAM J
		CENTRAL INDEX KEY:			0001074500
		STANDARD INDUSTRIAL CLASSIFICATION:	RETAIL-CATALOG & MAIL-ORDER HOUSES [5961]
		ORGANIZATION NAME:           	07 Trade & Services
		STATE OF INCORPORATION:			MN
		FISCAL YEAR END:			1228

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-11689
		FILM NUMBER:		251398238

	MAIL ADDRESS:	
		STREET 1:		FAIR ISAAC CORPORATION
		STREET 2:		5 WEST MENDENHALL, SUITE 105
		CITY:			BOZEMAN
		STATE:			MT
		ZIP:			59715

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FAIR ISAAC CORP
		CENTRAL INDEX KEY:			0000814547
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-BUSINESS SERVICES, NEC [7389]
		ORGANIZATION NAME:           	07 Trade & Services
		EIN:				941499887
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		5 WEST MENDENHALL
		STREET 2:		SUITES 105
		CITY:			BOZEMAN
		STATE:			MT
		ZIP:			59715
		BUSINESS PHONE:		(406) 982-7276

	MAIL ADDRESS:	
		STREET 1:		5 WEST MENDENHALL
		STREET 2:		SUITES 105
		CITY:			BOZEMAN
		STATE:			MT
		ZIP:			59715

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FAIR ISAAC & COMPANY INC
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
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<TYPE>4
<SEQUENCE>1
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<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
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    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-10-14</periodOfReport>

    <issuer>
        <issuerCik>0000814547</issuerCik>
        <issuerName>FAIR ISAAC CORP</issuerName>
        <issuerTradingSymbol>FICO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001074500</rptOwnerCik>
            <rptOwnerName>LANSING WILLIAM J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5 WEST MENDENHALL, SUITE 105</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOZEMAN</rptOwnerCity>
            <rptOwnerState>MT</rptOwnerState>
            <rptOwnerZipCode>59715</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>President and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>1</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-10-14</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
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            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>360</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1647.2431</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>42847</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
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            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>100</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1648.1796</value>
                    <footnoteId id="F2"/>
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                <transactionAcquiredDisposedCode>
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                </transactionAcquiredDisposedCode>
            </transactionAmounts>
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                <sharesOwnedFollowingTransaction>
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                </sharesOwnedFollowingTransaction>
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        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
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            <transactionDate>
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            <deemedExecutionDate></deemedExecutionDate>
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                <equitySwapInvolved>false</equitySwapInvolved>
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            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>109</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1650.1648</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>42638</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-10-14</value>
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            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
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                <equitySwapInvolved>false</equitySwapInvolved>
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            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>100</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1651.17</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>42538</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-10-14</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
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            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>242</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1652.5634</value>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>42296</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-10-14</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
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            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>158</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1653.7999</value>
                    <footnoteId id="F5"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>42138</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>313351</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Lansing Revocable Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>18300</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Lansing 2025 Grantor Retained Annuity Trust (GRAT)</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">This transaction was executed in multiple trades at prices ranging from $1,646.83 to $1,647.68. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.</footnote>
        <footnote id="F2">This transaction was executed in multiple trades at prices ranging from $1,647.92 to $1,648.76. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.</footnote>
        <footnote id="F3">This transaction was executed in multiple trades at prices ranging from $1,650.0850 to $1,650.76. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.</footnote>
        <footnote id="F4">This transaction was executed in multiple trades at prices ranging from $1,652.26 to $1,653.03. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.</footnote>
        <footnote id="F5">This transaction was executed in multiple trades at prices ranging from $1,653.41 to $1,653.99. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.</footnote>
    </footnotes>

    <remarks>Part 2 of a 2 part filing.</remarks>

    <ownerSignature>
        <signatureName>/s/ Carrie H. Darling, Attorney-in-fact</signatureName>
        <signatureDate>2025-10-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
