-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 TXRkwIaFBOwABXGeUSlSTTrxVzEywz62r1BSeIRlLXx3AIq8JydTWLqUpeCzP3Qh
 j3pS1yI2yMqp1bI8kfpzwA==

<SEC-DOCUMENT>0001319161-09-000009.txt : 20090909
<SEC-HEADER>0001319161-09-000009.hdr.sgml : 20090909
<ACCEPTANCE-DATETIME>20090909180636
ACCESSION NUMBER:		0001319161-09-000009
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090908
FILED AS OF DATE:		20090909
DATE AS OF CHANGE:		20090909

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Grann Phyllis E
		CENTRAL INDEX KEY:			0001369909

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32502
		FILM NUMBER:		091061342

	MAIL ADDRESS:	
		STREET 1:		WARNER MUSIC GROUP
		STREET 2:		75 ROCKEFELLER PLAZA
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10019

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Warner Music Group Corp.
		CENTRAL INDEX KEY:			0001319161
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-AMUSEMENT & RECREATION SERVICES [7900]
		IRS NUMBER:				134271875
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		75 ROCKEFELLER PLAZA
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10019
		BUSINESS PHONE:		212-275-2000

	MAIL ADDRESS:	
		STREET 1:		75 ROCKEFELLER PLAZA
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10019

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	WMG Parent Corp.
		DATE OF NAME CHANGE:	20050228
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-09-08</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001319161</issuerCik>
        <issuerName>Warner Music Group Corp.</issuerName>
        <issuerTradingSymbol>WMG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001369909</rptOwnerCik>
            <rptOwnerName>Grann Phyllis E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>WARNER MUSIC GROUP</rptOwnerStreet1>
            <rptOwnerStreet2>75 ROCKEFELLER PLAZA</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2009-09-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10736</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.1934</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>35661</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2009-09-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>9264</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.3091</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>35661</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The transaction was executed in multiple trades at prices ranging from $4.18 to $4.21.  The price reported above reflects the weighted average sale price.</footnote>
        <footnote id="F2">This transaction was executed in multiple trades at prices ranging from $4.19 to $4.38.  The price reported above reflects the weighted average sale price.</footnote>
        <footnote id="F3">The Reporting Person hereby undertakes to provide upon request by the staff of the Securities and Exchange Commission, Warner Music Group Corp. or a security holder of Warner Music Group Corp., full information regarding the number of shares and prices at which each transaction was effected.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Trent Tappe as attorney-in-fact</signatureName>
        <signatureDate>2009-09-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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