<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-09-24</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001741530</issuerCik>
        <issuerName>Qfin Holdings, Inc.</issuerName>
        <issuerTradingSymbol>QFIN</issuerTradingSymbol>
        <issuerForeignTradingSymbol>3660</issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001305509</rptOwnerCik>
            <rptOwnerName>Yan Andrew Y</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>true</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>FLAT 9, 39 DEEP WATER BAY ROAD,</rptOwnerStreet1>
            <rptOwnerStreet2>DEEP WATER BAY</rptOwnerStreet2>
            <rptOwnerCity>HONG KONG</rptOwnerCity>
            <rptOwnerNonUSStateTerritory></rptOwnerNonUSStateTerritory>
            <rptOwnerCountry>K3</rptOwnerCountry>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription>HONG KONG</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>American Depositary Shares</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2026-09-24</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>330000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.5226</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>326700</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Morning Star Resources Ltd</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>American Depositary Shares</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2026-09-25</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>326700</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.3606</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Morning Star Resources Ltd</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class A Ordinary Shares</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>850</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Morning Star Resources Ltd</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Each American Depositary Share represents two (2) Class A ordinary shares of the Issuer.</footnote>
        <footnote id="F2">Represents weighted average sales price. The American Depositary Shares were sold on September 24, 2026, at prices ranging from US$7.47 to US$7.61. The Reporting Person will provide upon request, to the Securities and Exchange Commission, the Issuer or any security holder of the Issuer, full information regarding the number of American Depositary Shares sold at each separate price.</footnote>
        <footnote id="F3">Represents weighted average sales price. The American Depositary Shares were sold on September 25, 2026, at prices ranging from US$7.30 to US$7.45. The Reporting Person will provide upon request, to the Securities and Exchange Commission, the Issuer or any security holder of the Issuer, full information regarding the number of American Depositary Shares sold at each separate price.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Andrew Y Yan</signatureName>
        <signatureDate>2026-09-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
