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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2025-07-14</periodOfReport>

    <dateOfOriginalSubmission>2025-12-15</dateOfOriginalSubmission>

    <issuer>
        <issuerCik>0001524566</issuerCik>
        <issuerName>WEALTHFRONT CORP</issuerName>
        <issuerTradingSymbol>WLTH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002082564</rptOwnerCik>
            <rptOwnerName>Fortunato David</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WEALTHFRONT CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>261 HAMILTON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>PALO ALTO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94301</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>CEO and President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-12-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>91507</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>14</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>61996</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Spouse</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The transaction represents the number of shares of Common Stock withheld by the Issuer to satisfy tax withholding liabilities in connection with the net settlement of restricted stock units.</footnote>
    </footnotes>

    <remarks>The Form 4 filed on December 15, 2025 is being amended hereby to include in Table I above the number of restricted stock units which were withheld on December 11, 2025 to satisfy tax withholding liabilities incurred by the reporting person's spouse in connection with the vesting and settlement of restricted stock units directly held by her.  For avoidance of doubt, after giving effect to all transactions originally reported on such Form 4, as amended hereby, the reporting person's spouse directly held 61,996 shares of the Issuer's Common Stock.  Any subsequent Forms 4 filed by the reporting person through the date of this amendment should be read to incorporate this correction in the context of any transactions reported therein.</remarks>

    <ownerSignature>
        <signatureName>/s/ Lauren Lin, as Attorney-in-Fact</signatureName>
        <signatureDate>2025-12-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
