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SEC EDGAR · Insider purchase

VST: BURKE JAMES A reported buying shares

2 reported purchases of non-derivative securities. Code P includes open-market and private purchases; it does not establish motive.

Follow VST
Became public
Sep 2, 2026, 9:38 AM EDT
Event / period date
Aug 31, 2026
Collected
Nov 9, 2026, 5:36 AM EST

Why this is connected

This filing identifies Vistra Corp. as the issuer of the security. The company's SEC identifier connects it to VST.

Open the original source ↗Follow company activity in VST

Reported transactions

BURKE JAMES A (President and CEO)

2,200 shares · Common Stock

Aug 31, 2026 · $135.99 per share

4,465 shares · Common Stock

Sep 1, 2026 · $135.25 per share

Value calculated from the reported shares and prices: $903,069.25.

Code P covers open-market and private purchases. Grants, option exercises, and tax withholding are excluded from purchase results. Read the source footnotes for ownership and pricing details.

Source evidence

Read the source excerpt or record
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-08-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001692819</issuerCik>
        <issuerName>Vistra Corp.</issuerName>
        <issuerTradingSymbol>VST</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001268406</rptOwnerCik>
            <rptOwnerName>BURKE JAMES A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>6555 SIERRA DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>IRVING</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75039</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-08-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2200</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>135.99</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1141887</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By JAMEB, LP, a limited partnership jointly owned by Reporting Person and his spouse</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-09-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4465</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>135.25</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1146352</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By JAMEB, LP, a limited partnership jointly owned by Reporting Person and his spouse</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>61690</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>34000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By the James A. Burke 2012 Irrevocable Trust, dated 12/03/2012</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>259</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By the Marti E. Burke 2012 Irrevocable Trust, dated 10/16/2012</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents a weighted-average price. These shares were purchased in multiple transactions at prices ranging from $135.92 to $136.00, inclusive. For all transactions reported in this Form 4 utilizing a weighted-average price, the reporting person will provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares purchased at each price within the range.</footnote>
        <footnote id="F2">Represents a weighted-average price. These shares were purchased in multiple transactions at prices ranging from $135.00 to $135.50, inclusive. For all transactions reported in this Form 4 utilizing a weighted-average price, the reporting person will provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares purchased at each price within the range.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Yuki Whitmire, Attorney-in-Fact</signatureName>
        <signatureDate>2026-09-01</signatureDate>
    </ownerSignature>
</ownershipDocument>

Congressional trading in VST

These disclosures provide context. Their presence does not establish a link between a trader and the event.

Original documents control. Public records can be amended, and company connections may require interpretation. Nothing here is investment advice.