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

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-08-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001769628</issuerCik>
        <issuerName>CoreWeave, Inc.</issuerName>
        <issuerTradingSymbol>CRWV</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001352851</rptOwnerCik>
            <rptOwnerName>Magnetar Financial LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>1603 ORRINGTON AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>13TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>EVANSTON</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001353085</rptOwnerCik>
            <rptOwnerName>Magnetar Capital Partners LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>1603 ORRINGTON AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>13TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>EVANSTON</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001368026</rptOwnerCik>
            <rptOwnerName>Supernova Management LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>1603 ORRINGTON AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>13TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>EVANSTON</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001953511</rptOwnerCik>
            <rptOwnerName>Snyderman David J.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>1603 ORRINGTON AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>13TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>EVANSTON</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1891986</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Footnotes</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Magnetar Financial LLC (&quot;Magnetar Financial&quot;) serves as the investment adviser to Magnetar Xing He Master Fund Ltd (&quot;Magnetar Fund&quot;).</footnote>
        <footnote id="F2">Magnetar Capital Partners LP (&quot;Magnetar Capital Partners&quot;) is the sole member and parent holding company of Magnetar Financial. Supernova Management LLC (&quot;Supernova Management&quot;) is the general partner of Magnetar Capital Partners. The administrative manager of Supernova Management is David J. Snyderman, a citizen of the United States of America.</footnote>
        <footnote id="F3">Each of the Magnetar Fund, Magnetar Financial, Magnetar Capital Partners, Supernova Management and David J. Snyderman disclaims beneficial ownership of these shares of Common Stock of the Issuer, except to the extent of its or his pecuniary interest therein.</footnote>
        <footnote id="F4">These securities are held directly by Magnetar Xing He Master Fund Ltd.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Hayley A. Stein, Attorney-in-Fact for David J. Snyderman, as Administrative Manager of Supernova Management LLC, which is the General Partner of Magnetar Capital Partners LP, which is in turn the Sole Member of Magnetar Financial LLC</signatureName>
        <signatureDate>2026-08-14</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Hayley A. Stein, Attorney-in-Fact for David J. Snyderman, as Administrative Manager of Supernova Management LLC, which is the General Partner of Magnetar Capital Partners LP</signatureName>
        <signatureDate>2026-08-14</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Hayley A. Stein, Attorney-in-Fact for David J. Snyderman, as Administrative Manager of Supernova Management LLC</signatureName>
        <signatureDate>2026-08-14</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Hayley A. Stein, Attorney-in-Fact for David J. Snyderman</signatureName>
        <signatureDate>2026-08-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
