<SEC-DOCUMENT>0001209191-17-051191.txt : 20170905
<SEC-HEADER>0001209191-17-051191.hdr.sgml : 20170905
<ACCEPTANCE-DATETIME>20170905134018
ACCESSION NUMBER:		0001209191-17-051191
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170901
FILED AS OF DATE:		20170905
DATE AS OF CHANGE:		20170905

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:		171068179

	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:			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:		171068178

	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:		171068176

	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:		171068177

	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:			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:		171068180

	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

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>2017-09-01</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>2017-09-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>18511134</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>118090823</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;MPCI&quot;), MPLX GP LLC (the &quot;GP&quot;), MPLX Logistics Holdings LLC (&quot;Logistics&quot;) and MPLX Holdings Inc. (&quot;Holdings&quot;). MPCI, a direct wholly-owned subsidiary of MPC, owns all of the membership interests in both the GP and Logistics and all of the shares of stock of Holdings. Accordingly, the GP, Logistics and Holdings are all indirect wholly-owned subsidiaries of MPC.</footnote>
        <footnote id="F2">Pursuant to the Membership Interests and Shares Contributions Agreement among the Issuer, Logistics, Holdings, the GP and MPCI, on 9/1/2017, MPCI agreed to contribute: the membership interests of Lincoln Pipeline LLC, which holds a 35% interest in Illinois Extension Pipeline Company, L.L.C.; the membership interests of MPL Louisiana Holdings LLC, which holds a 40.7% interest in LOOP LLC; a 58.52% interest in LOCAP LLC; and a 24.51% interest in Explorer Pipeline Company, to the Issuer for $420 million in cash and equity consideration valued at $630 million, consisting of: (i) 13,719,017 common units issued to the GP, (ii) 3,350,893 common units issued to Logistics, (iii) 1,441,224 common units issued to Holdings and (iv) 377,778 general partner units issued to the GP. The units issued were calculated by dividing $630 million by $33.3529, the simple average of the 10 day trading volume weighted average price of a common unit for the 10 trading days ending 8/31/2017.</footnote>
        <footnote id="F3">The GP directly owns 8,306,911 general partner units, representing its 2% general partner interest in the Issuer. MPCI owns all of the membership interest in the GP and MPC owns all of the membership interest in MPCI.  Accordingly, MPC and MPCI both may be deemed to indirectly beneficially own the securities of the Issuer directly held by the GP, but disclaim beneficial ownership except to the extent of their respective pecuniary interests therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, Marathon Petroleum Corporation</signatureName>
        <signatureDate>2017-09-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, MPC Investment LLC</signatureName>
        <signatureDate>2017-09-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Molly R. Benson, Vice President, Corporate Secretary and Chief Compliance Officer, MPLX GP LLC</signatureName>
        <signatureDate>2017-09-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Molly R. Benson,  Assistant Secretary, MPLX Logistics Holdings LLC</signatureName>
        <signatureDate>2017-09-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Molly R. Benson,  Director and Secretary, MPLX Holdings Inc.</signatureName>
        <signatureDate>2017-09-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
