<SEC-DOCUMENT>0001209191-19-044119.txt : 20190801
<SEC-HEADER>0001209191-19-044119.hdr.sgml : 20190801
<ACCEPTANCE-DATETIME>20190801191833
ACCESSION NUMBER:		0001209191-19-044119
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20190730
FILED AS OF DATE:		20190801
DATE AS OF CHANGE:		20190801

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Goff Gregory James
		CENTRAL INDEX KEY:			0001490987

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35714
		FILM NUMBER:		19994065

	MAIL ADDRESS:	
		STREET 1:		19100 RIDGEWOOD PARKWAY
		CITY:			SAN ANTONIO
		STATE:			TX
		ZIP:			78259

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MPLX LP
		CENTRAL INDEX KEY:			0001552000
		STANDARD INDUSTRIAL CLASSIFICATION:	PIPE LINES (NO NATURAL GAS) [4610]
		IRS NUMBER:				270005456
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		200 E. HARDIN STREET
		CITY:			FINDLAY
		STATE:			OH
		ZIP:			45840
		BUSINESS PHONE:		(419) 421-2159

	MAIL ADDRESS:	
		STREET 1:		200 E. HARDIN STREET
		CITY:			FINDLAY
		STATE:			OH
		ZIP:			45840
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-07-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001552000</issuerCik>
        <issuerName>MPLX LP</issuerName>
        <issuerTradingSymbol>MPLX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001490987</rptOwnerCik>
            <rptOwnerName>Goff Gregory James</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MPLX LP</rptOwnerStreet1>
            <rptOwnerStreet2>200 E. HARDIN STREET</rptOwnerStreet2>
            <rptOwnerCity>FINDLAY</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>45840</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Units (Limited Partner Interests)</value>
            </securityTitle>
            <transactionDate>
                <value>2019-07-30</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>340928.151</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>389801.46</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On July 30, 2019 (the &quot;Effective Time&quot;), pursuant to the Agreement and Plan of Merger, dated as of May 7, 2019 (the &quot;Merger Agreement&quot;), by and among the Issuer, Andeavor Logistics LP (&quot;ANDX&quot;), Tesoro Logistics GP, LLC, MPLX GP LLC and MPLX MAX LLC (&quot;Merger Sub&quot;), Merger Sub merged with and into ANDX (the &quot;Merger&quot;), with ANDX surviving the Merger as a wholly owned subsidiary of the Issuer.</footnote>
        <footnote id="F2">Pursuant to the Merger Agreement, at the Effective Time, each common unit representing a limited partner interest in ANDX held by the Reporting Person was converted into the right to receive 1.135 common units (the &quot;Public Unitholder Exchange Ratio&quot;) representing limited partner interests in the Issuer (such conversion, the &quot;Common Unit Conversion&quot;). As a result of the Common Unit Conversion, the Reporting Person received 193,490.151 common units representing limited partnership interests in the Issuer. The closing price of common units representing limited partner interests in the Issuer (&quot;MPLX Common Units&quot;) on July 29, 2019, which was the last complete trading day prior to the Effective Time, was $28.51 as reported on the New York Stock Exchange.</footnote>
        <footnote id="F3">Pursuant to the Merger Agreement, each phantom unit of ANDX held by the Reporting Person was converted, at the Effective Time, into a phantom unit denominated in common units representing limited partner interests in the Issuer (each, a &quot;Converted MPLX Phantom Unit&quot;), with the number of such common units subject to each Converted MPLX Phantom Unit equal to the product of (x) the number of common units representing limited partnership interests in ANDX subject to such phantom units of ANDX held by the Reporting Person immediately prior to Effective Time multiplied by (y) the Public Unitholder Exchange Ratio (such conversion, the &quot;Phantom Unit Conversion&quot;). As a result of the Phantom Unit Conversion, the Reporting Person received 147,438 phantom units in respect of MPLX Common Units.</footnote>
        <footnote id="F4">All reported amounts are estimated as of August 1, 2019 based on preliminary information with respect to the Merger. Final amounts will be reported in a subsequent filing.</footnote>
    </footnotes>

    <remarks>The Reporting Person is a Director of MPLX GP LLC, the general partner of the Issuer.  The Issuer is managed by the directors and executive officers of MPLX GP LLC.</remarks>

    <ownerSignature>
        <signatureName>/s/ Molly R. Benson, Attorney-in-Fact for Gregory James Goff</signatureName>
        <signatureDate>2019-08-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
