<SEC-DOCUMENT>0001209191-17-018011.txt : 20170303
<SEC-HEADER>0001209191-17-018011.hdr.sgml : 20170303
<ACCEPTANCE-DATETIME>20170303184530
ACCESSION NUMBER:		0001209191-17-018011
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170301
FILED AS OF DATE:		20170303
DATE AS OF CHANGE:		20170303

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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MPLX Holdings Inc.
		CENTRAL INDEX KEY:			0001683291
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35714
		FILM NUMBER:		17665970

	BUSINESS ADDRESS:	
		STREET 1:		539 SOUTH MAIN STREET
		CITY:			FINDLAY
		STATE:			OH
		ZIP:			45840
		BUSINESS PHONE:		419-421-2159

	MAIL ADDRESS:	
		STREET 1:		539 SOUTH MAIN STREET
		CITY:			FINDLAY
		STATE:			OH
		ZIP:			45840

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MPLX Logistics Holdings LLC
		CENTRAL INDEX KEY:			0001551994
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35714
		FILM NUMBER:		17665971

	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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MPLX GP LLC
		CENTRAL INDEX KEY:			0001551999
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35714
		FILM NUMBER:		17665972

	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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MPC Investment LLC
		CENTRAL INDEX KEY:			0001560713
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35714
		FILM NUMBER:		17665973

	BUSINESS ADDRESS:	
		STREET 1:		539 S. MAIN STREET
		CITY:			FINDLAY
		STATE:			OH
		ZIP:			45840
		BUSINESS PHONE:		(419) 421-2159

	MAIL ADDRESS:	
		STREET 1:		539 S. MAIN STREET
		CITY:			FINDLAY
		STATE:			OH
		ZIP:			45840

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Marathon Petroleum Corp
		CENTRAL INDEX KEY:			0001510295
		STANDARD INDUSTRIAL CLASSIFICATION:	PETROLEUM REFINING [2911]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35714
		FILM NUMBER:		17665974

	BUSINESS ADDRESS:	
		STREET 1:		539 SOUTH MAIN STREET
		CITY:			FINDLAY
		STATE:			OH
		ZIP:			45840-3229
		BUSINESS PHONE:		419-421-2159

	MAIL ADDRESS:	
		STREET 1:		539 SOUTH MAIN STREET
		CITY:			FINDLAY
		STATE:			OH
		ZIP:			45840-3229
</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>2017-03-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001510295</rptOwnerCik>
            <rptOwnerName>Marathon Petroleum Corp</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>539 S. MAIN STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>FINDLAY</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>45840</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001560713</rptOwnerCik>
            <rptOwnerName>MPC Investment LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>539 S. MAIN STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>FINDLAY</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>45840</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001551999</rptOwnerCik>
            <rptOwnerName>MPLX GP LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 E. HARDIN STREET</rptOwnerStreet1>
            <rptOwnerStreet2></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>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001551994</rptOwnerCik>
            <rptOwnerName>MPLX Logistics Holdings LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 E. HARDIN STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>FINDLAY</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>45840</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001683291</rptOwnerCik>
            <rptOwnerName>MPLX Holdings Inc.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>539 S. MAIN ST.</rptOwnerStreet1>
            <rptOwnerStreet2></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>2017-03-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>12960376</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>99579689</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This Form 4 is filed jointly by Marathon Petroleum Corporation (&quot;MPC&quot;), MPC Investment LLC (&quot;MPC Investment&quot;), MPLX GP LLC (the &quot;General Partner&quot;), MPLX Logistics Holdings LLC (&quot;MPLX Logistics&quot;) and MPLX Holdings Inc. (&quot;MPLX Holdings&quot;). MPC Investment, a direct wholly-owned subsidiary of MPC, owns all of the membership interests in both the General Partner and MPLX Logistics and all of the shares of stock of MPLX Holdings. Accordingly, the General Partner, MPLX Logistics and MPLX Holdings are indirect wholly-owned subsidiaries of MPC.</footnote>
        <footnote id="F2">The General Partner directly owns 7,636,916 general partner units, representing its 2% general partner interest in the Issuer. MPC Investment owns all of the membership interest in the General Partner and MPC owns all of the membership interest in MPC Investment. Accordingly, MPC and MPC Investment both may be deemed to indirectly beneficially own the securities of the Issuer directly held by the General Partner, but disclaim beneficial ownership except to the extent of their respective pecuniary interests therein.</footnote>
        <footnote id="F3">Pursuant to the Membership Interests Contributions Agreement among the Issuer, MPLX Logistics, MPLX Holdings, the General Partner and MPC Investment, on March 1, 2017, MPC Investment agreed to contribute the outstanding membership interests in Hardin Street Transportation LLC, Woodhaven Cavern LLC and MPLX Terminals LLC through a series of intercompany contributions to the Issuer for approximately $1.511 billion in cash and equity consideration valued at approximately $504 million, consisting of: (i) 9,197,900 common units issued to the General Partner, (ii) 2,630,427 common units issued to MPLX Logistics, (iii) 1,132,049 common units issued to MPLX Holdings and (iv) 264,497 general partner units issued to the General Partner. The common units and general partner units issued were calculated by dividing $503,750,000 by $38.0911, the simple average of the volume weighted average price of a common unit for the 10 trading days ending February 28, 2017.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, Marathon Petroleum Corporation</signatureName>
        <signatureDate>2017-03-03</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, MPC Investment LLC</signatureName>
        <signatureDate>2017-03-03</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, MPLX GP LLC</signatureName>
        <signatureDate>2017-03-03</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Molly R. Benson,  Assistant Secretary, MPLX Logistics Holdings LLC</signatureName>
        <signatureDate>2017-03-03</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Molly R. Benson,  Director and Secretary, MPLX Holdings Inc.</signatureName>
        <signatureDate>2017-03-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
