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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2008-01-11</periodOfReport>

    <dateOfOriginalSubmission>2008-01-15</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000878088</issuerCik>
        <issuerName>PAR PHARMACEUTICAL COMPANIES, INC.</issuerName>
        <issuerTradingSymbol>PRX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001402404</rptOwnerCik>
            <rptOwnerName>LUBATKIN VERONICA</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PAR PHARMACEUTICAL COMPANIES, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>300 TICE BOULEVARD</rptOwnerStreet2>
            <rptOwnerCity>WOODCLIFF LAKE</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07677</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Exec VP, CFO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-01-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>36849</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>74025</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Award of shares of Restricted Stock under the Company's 2004 Performance Equity Plan.  33% of the shares of Restricted Stock vest as follows:  25% vest on the first anniversary of the date of grant and an additional 25% vest on each anniversary thereafter until the 33% are fully vested; 67% of the shares of Restricted Stock vest as follows:  over a three-year period, upon the achievement by the Company of defined goals of Total Returns to Shareholders relative to a defined peer group of pharmaceutical companies.</footnote>
        <footnote id="F2">The closing price of the Company's Common Stock as reported by The New York Stock Exchange, Inc. on the date of grant was $21.71.</footnote>
        <footnote id="F3">This Amendment is being filed to correct the total number of securities beneficially owned in Column 5 of Table I; includes all outstanding shares of Restricted Stock and Restricted Stock Units held by Ms. Lubatkin.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Marian E. Gustafson for Veronica Lubatkin</signatureName>
        <signatureDate>2008-01-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
