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

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-03-23</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001258602</issuerCik>
        <issuerName>NELNET INC</issuerName>
        <issuerTradingSymbol>NNI</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001667769</rptOwnerCik>
            <rptOwnerName>Peterson Adam K</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>1601 DODGE STREET, SUITE 3300</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>OMAHA</rptOwnerCity>
            <rptOwnerState>NE</rptOwnerState>
            <rptOwnerZipCode>68102</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>See below</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001618333</rptOwnerCik>
            <rptOwnerName>MAGNOLIA CAPITAL FUND, LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>1601 DODGE STREET, SUITE 3300</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>OMAHA</rptOwnerCity>
            <rptOwnerState>NE</rptOwnerState>
            <rptOwnerZipCode>68102</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>See remarks</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001618376</rptOwnerCik>
            <rptOwnerName>MAGNOLIA GROUP, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>1601 DODGE STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 3300</rptOwnerStreet2>
            <rptOwnerCity>OMAHA</rptOwnerCity>
            <rptOwnerState>NE</rptOwnerState>
            <rptOwnerZipCode>68102</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>See remarks</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1678520</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">1,668,976 of the reported shares are directly owned by Magnolia Capital Fund, LP, of which The Magnolia Group, LLC (&quot;TMG&quot;) is the general partner and investment manager. Adam K. Peterson (&quot;Mr. Peterson&quot;) is the managing member of TMG. TMG and Mr. Peterson could both be deemed to share indirect beneficial ownership of 1,668,976 shares of Common Stock of Nelnet Inc held by Magnolia Capital Fund, LP. Mr. Peterson holds directly 9,544 shares of Class A Common Stock for his own account. In reference to Item 3. Date of Earliest Transaction, March 23, 2026 is used as on that date, Adam Peterson notified NelNet, Inc. of his resignation from the Board of Directors effective immediately. As such, this 'Exit' Form 4 is voluntarily filed as confirmation that Adam Peterson is no longer subject to this filing.</footnote>
    </footnotes>

    <remarks>TMG and Mr. Peterson disclaim beneficial ownership except to the extent of their respective pecuniary interests therein of shares except the 9,544 shares Mr. Peterson directly owns, and this report shall not be deemed an admission of beneficial ownership of these securities for Section 16 or for any other purposes.</remarks>

    <ownerSignature>
        <signatureName>/s/ Adam K. Peterson</signatureName>
        <signatureDate>2026-04-27</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Adam K. Peterson on behalf of the Magnolia Capital Fund, LP by its General Partner, The Magnolia Group, LLC</signatureName>
        <signatureDate>2026-04-27</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Adam K. Peterson, managing member on behalf of The Magnolia Group, LLC</signatureName>
        <signatureDate>2026-04-27</signatureDate>
    </ownerSignature>
</ownershipDocument>