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

    <schemaVersion>X0607</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2026-08-24</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001850351</issuerCik>
        <issuerName>Liftoff Mobile, Inc.</issuerName>
        <issuerTradingSymbol>LFTO</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002151437</rptOwnerCik>
            <rptOwnerName>Redbird ML Holdco L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O BLACKSTONE INC.</rptOwnerStreet1>
            <rptOwnerStreet2>345 PARK AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10154</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002151436</rptOwnerCik>
            <rptOwnerName>Redbird ML Holdco GP LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O BLACKSTONE INC.</rptOwnerStreet1>
            <rptOwnerStreet2>345 PARK AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10154</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>83831109</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On August 24, 2026, BCP Redbird Aggregator L.P. contributed 83,831,109 shares of common stock (the &quot;Common Stock&quot;) of Liftoff Mobile, Inc. (&quot;Issuer&quot;) previously held directly by it to its wholly-owned subsidiary Redbird ML Holdco LP. No securities of the Issuer were purchased, sold or otherwise transferred in connection with the contributions described herein.</footnote>
        <footnote id="F2">Reflects shares of Common Stock of the Issuer held directly by Redbird ML Holdco LP. Redbird ML Holdco GP LLC is the general partner of Redbird ML Holdco LP.  BCP Redbird Aggregator L.P. is the sole limited partner of Redbird ML Holdco LP and the managing member of Redbird ML Holdco GP LLC. BCP VII Holdings Manager L.L.C. is the general partner of BCP Redbird Aggregator L.P. Blackstone Management Associates VII L.L.C. is the sole member of BCP VII Holdings Manager L.L.C. BMA VII L.L.C. is the sole member of Blackstone Management Associates VII L.L.C. Blackstone Holdings III L.P. is the managing member of BMA VII L.L.C. Blackstone Holdings III GP L.P. is the general partner of Blackstone Holdings III L.P. Blackstone Holdings III GP Management L.L.C. is the general partner of Blackstone Holdings III GP L.P.</footnote>
        <footnote id="F3">Blackstone Inc. is the sole member of Blackstone Holdings III GP Management L.L.C. The sole holder of the Series II preferred stock of Blackstone Inc. is Blackstone Group Management L.L.C. Blackstone Group Management L.L.C. is wholly-owned by Blackstone's senior managing directors and controlled by its founder, Stephen A. Schwarzman.</footnote>
        <footnote id="F4">Information with respect to each of the Reporting Persons is given solely by such Reporting Person, and no Reporting Person has responsibility for the accuracy or completeness of information supplied by another Reporting Person.</footnote>
        <footnote id="F5">Redbird ML Holdco GP LLC may be deemed to beneficially own the shares of Common Stock of the Issuer directly held by Redbird ML Holdco LP but disclaims beneficial ownership of the securities held by Redbird ML Holdco LP, except to the extent of its pecuniary interest therein, and, this filing shall not be deemed an admission that Redbird ML Holdco GP LLC is the beneficial owner of the reported securities for purposes of Section 16 or for any other purpose.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>REDBIRD ML HOLDCO LP, By: Redbird ML Holdco GP LLC, its general partner, By: /s/ Robert Brooks Name: Robert Brooks Title: Authorized Signatory</signatureName>
        <signatureDate>2026-09-03</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>REDBIRD ML HOLDCO GP LLC, By: /s/ Robert Brooks Name: Robert Brooks Title: Authorized Signatory</signatureName>
        <signatureDate>2026-09-03</signatureDate>
    </ownerSignature>
</ownershipDocument>