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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-08-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001055404</rptOwnerCik>
            <rptOwnerName>LEPORE PATRICK G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PAR PHARMACEUTICAL, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>300 TICE BLVD</rptOwnerStreet2>
            <rptOwnerCity>WOODCLIFF LAKE</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07677</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-08-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>6690</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>15.23</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>174030</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Limited Partnership</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Surrender of shares in payment of tax withholding due as a result of the vesting of Restricted Stock granted in accordance with Rule 16b-3.</footnote>
        <footnote id="F2">Includes all outstanding shares of Restricted Stock and Restricted Stock Units held by Mr. LePore.</footnote>
        <footnote id="F3">The shares are held by Park Street Investors, L.P. (&quot;PSI&quot;), a Delaware limited partnership.  The General Partner of PSI is Park Street Investment Corporation (&quot;PSIC&quot;), a Delaware corporation, of which Mr. LePore and his spouse are officers and directors and together own a majority of the outstanding stock of PSIC.</footnote>
        <footnote id="F4">The shares are held by the Patrick LePore Revocable Trust of 2002, of which Mr. LePore is the Grantor, Trustee and beneficiary.</footnote>
    </footnotes>

    <remarks>LIMITED POWER OF ATTORNEY: KNOW ALL MEN BY THESE PRESENTS, that the undersigned does hereby constitute and appoint MARIAN E. GUSTAFSON with full power to act, as his true and lawful attorney-in-fact and agent, with full power of substitution and resubstitution, for him and in his name, place and stead, in any and all capacities, and to do any and all acts and things in his name and on his behalf, to execute any and all documents and instruments, which said attorney-in-fact may deem necessary or advisable to enable him to comply with the reporting requirements pursuant to Section 16 of the Securities Exchange Act of 1934, as amended, including but not limited to Form 4-Statement of Changes in Beneficial Ownership and Form 5-Annual Statement of Changes in Beneficial Ownership, relating to his ownership in Par Pharmaceutical Companies, Inc. (the &quot;Company&quot;) for the period October 1, 2007 through and including September 30, 2008; and to file the same, and all other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorney-in-fact and agent, full power and authority to do and perform each and every act and thing requisite and necessary to be done as fully to all intents and purposes as the undersigned might or could do in person, hereby ratifying and confirming all that the said attorney-in-fact and agent may lawfully do or cause to be done by virtue thereof.  /s/ Patrick G. LePore  Dated: 10/4/2007</remarks>

    <ownerSignature>
        <signatureName>By Marian E. Gustafson for Patrick G. LePore</signatureName>
        <signatureDate>2008-08-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
