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(1)	Pursuant to Rule 416 of the Securities Act of 1933 (the “Securities Act”), the Registration Statement also includes an indeterminable number of common units that may be issued by MPLX LP in connection with a dividend, split or other distribution with respect to, or in exchange or substitution for, such common units.

(2)	Calculated in accordance with Rule 457(c) of the Securities Act based on the average high and low prices of the common units as reported on the New York Stock Exchange on May 11, 2016.

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•	our Annual Report on Form 10-K for the fiscal year ended December 31, 2015 (Part II, Item 6, Part II, Item 7 and Part II, Item 8 have been superseded by recasted information filed by MPLX on a Current Report on Form 8-K on May 2, 2016);

•	our Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 2016;

•	our Current Reports on Form 8-K and Form 8-K/A, as applicable, filed on January 4, 2016, January 29, 2016, February 22, 2016, March 4, 2016 (two reports), March 17, 2016, April 6, 2016, April 29, 2016, May 2, 2016 (two reports) and May 16, 2016;

•	the description of the common units representing limited partner interests in MPLX as set forth in MPLX’s Registration Statement on Form 8-A (Registration No. 001-35714), filed with the SEC on October 23, 2012 under the Exchange Act, and all amendments or reports filed with the SEC for the purpose of updating such description;

•	Item 8 of MarkWest’s Annual Report on Form 10-K for the fiscal year ended December 31, 2014 (SEC File No. 001-31239); and

•	Part 1, Item 1 of MarkWest’s Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2015, June 30, 2015 and September 30, 2015 (SEC File No. 001-31239).

•	future levels of revenues and other income, income from operations, net income attributable to MPLX, earnings per unit, adjusted EBITDA or distributable cash flow;

•	anticipated levels of regional, national and worldwide prices of crude oil, natural gas, natural gas liquids, which we refer to as“NGLs,” and refined products;

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•	anticipated levels of regional, national and worldwide prices of crude oil, natural gas, NGLs and refined products;

•	anticipated levels of drilling activity, production rates and volumes of throughput and crude oil, natural gas, NGLs, refined products or other hydrocarbon-based products;

•	future levels of capital, environmental or maintenance expenditures, general and administrative and other expenses;

•	the success or timing of completion of ongoing or anticipated capital or maintenance projects;

•	expectations regarding our merger with MarkWest and other acquisitions or divestitures of assets;

•	business strategies, growth opportunities and expected investments;

•	the effect of restructuring or reorganization of business components;

•	the potential effects of judicial or other proceedings on our business, financial condition, results of operations and cash flows;

•	the potential effects of changes in tariff rates on our business, financial condition, results of operations and cash flows;

•	the adequacy of our capital resources and liquidity, including, but not limited to, availability of sufficient cash flow to pay distributions and execute our business plan;

•	our ability to successfully implement our growth strategy, whether through organic growth or acquisitions;

•	capital market conditions, including the cost of capital, and our ability to raise adequate capital to execute our business plan and implement our growth strategy; and

•	the anticipated effects of actions of third parties such as competitors, or federal, foreign, state or local regulatory authorities, or plaintiffs in litigation.

•	changes in general economic, market or business conditions;

•	changes in our economic and financial condition;

•	risks and uncertainties associated with intangible assets, including any future goodwill or intangible assets impairment charges;

•	changes in producer customers’ drilling plans or in volumes of throughput of crude oil, natural gas, NGLs, refined products or other hydrocarbon-based products;

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•	changes in regional, national and worldwide prices of crude oil, natural gas, NGLs and refined products;

•	domestic and foreign supplies of crude oil and other feedstock, natural gas, NGLs and refined products such as gasoline, diesel fuel, jet fuel, home heating oil and petrochemicals;

•	foreign imports and exports of crude oil, refined products, natural gas and NGLs;

•	midstream and refining industry overcapacity or under capacity;

•	changes in the cost or availability of third-party vessels, pipelines, railcars and other means of transportation for crude oil, feedstocks, natural gas, NGLs and refined products;

•	the price, availability and acceptance of alternative fuels and alternative-fuel vehicles and laws mandating such fuels or vehicles;

•	fluctuations in consumer demand for refined products, natural gas and NGLs including seasonal fluctuations;

•	changes in maintenance capital expenditure requirements or changes in costs of planned capital projects;

•	political and economic conditions in nations that consume refined products, natural gas and NGLs, including the United States, and in crude oil producing regions, including the Middle East, Africa, Canada and South America;

•	actions taken by our competitors and the expansion and retirement of pipeline, processing, fractionation and treating capacity in response to market conditions;

•	changes in fuel and utility costs for our facilities;

•	failure to realize the benefits projected for capital projects, or cost overruns associated with such projects;

•	the ability to successfully implement growth strategies, whether through organic growth or acquisitions;

•	accidents or other unscheduled shutdowns affecting our pipelines, processing, fractionation and treating facilities or equipment, or those of our suppliers or customers or facilities upstream or downstream of our facilities;

•	unusual weather conditions and natural disasters;

•	disruptions due to equipment interruption or failure;

•	acts of war, terrorism or civil unrest that could impair our ability to gather, process, fractionate or transport crude oil, natural gas, NGLs or refined products;

•	legislative or regulatory action, which may adversely affect our business or operations;

•	rulings, judgments or settlements in litigation or other legal, tax or regulatory matters, including unexpected environmental remediation costs, in excess of any reserves or insurance coverage;

•	political pressure and influence of environmental groups upon the policies and decisions related to the production, gathering, processing, fractionation, refining, transportation and marketing of natural gas, oil, NGLs or other hydrocarbon-based fuels;

•	labor and material shortages;

•	the ability and willingness of parties with whom we have material relationships to perform their obligations to us;

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•	capital market conditions, increases in and availability of equity capital, changes in the availability of unsecured credit and changes affecting the credit markets generally; and

•	the other factors described in Item 1A. Risk Factors of our most recent Annual Report on Form 10-K filed with the SEC, in each case, as these risk factors are amended or supplemented by subsequent Quarterly Reports on Form 10-Q that are incorporated by reference into this prospectus.

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•	surety bond premiums to replace lost or stolen certificates, or to cover taxes and other governmental charges in connection therewith;

•	special charges for services requested by a holder of a common unit; and

•	other similar fees or charges.

•	automatically agrees to be bound by the terms and conditions of, and is deemed to have executed, the Partnership Agreement;

•	represents and warrants that the transferee has the right, power, authority and capacity to enter into the Partnership Agreement; and

•	gives the consents, waivers and approvals contained in the Partnership Agreement.

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(1)

On December 4, 2015, the selling unitholder, an affiliate of The Energy & Minerals Group, acquired 8,014,434 Common units and 7,981,756 Class B units, along with cash consideration, in exchange for 7,352,691 MarkWest common units and 7,981,756 MarkWest Class B units in connection with the Merger. Unless earlier converted upon a fundamental change or liquidation of MPLX, the Class B units automatically convert into the right to receive $6.20 cash and common units at a ratio of 1.09 common units for each Class B unit converted in two installments on July 1, 2016 and July 1, 2017 (with 3,990,878 Class B units converting on each such date). The members of the selling unitholder are NGP Midstream & Resources, LP (“NGP MR”), NGP M&R Offshore Holdings, LP (“NGP MR Offshore”), Midstream & Resources Follow-on Fund, LP (“MR FOF”), Liberty M&R SPV, LP (“Liberty”) and Liberty M&R SPV II, LP (“Liberty II”), all of which are affiliates of The Energy & Minerals Group. The general partner of NGP MR and NGP MR Offshore is NGP MR, LP (“MR GP”). The general partner of MR FOF, Liberty and Liberty II is M&R FOF GP, LP (“FOF GP” and, together with MR GP, the “M&R General Partners”). The general partner of MR GP is NGP MR GP, LLC, and John Raymond is Chief Executive Officer and Managing Partner of NGP MR GP, LLC. The general partner of FOF GP is M&R FOF, LLC, and John Raymond is the sole member of M&R FOF, LLC. NGP MR GP, LLC, M&R FOF, LLC. Mr. Raymond may be deemed to beneficially own the common units and Class B units held by M&R MWE Liberty, LLC. Each of NGP MR GP, LLC, M&R FOF, LLC and Mr. Raymond disclaim beneficial ownership of such common units and Class B units, except to the extent of any pecuniary interest therein.

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•	less, the amount of cash reserves established by our general partner to:

−	provide for the proper conduct of our business (including reserves for our future capital expenditures, anticipated future debt service requirements and refunds of collected rates reasonably likely to be refunded as a result of a settlement or hearing related to Federal Energy Regulatory Commission, or FERC, rate proceedings or rate proceedings under applicable law subsequent to that quarter);

−	comply with applicable law, any of our debt instruments or other agreements; or

−

provide funds for distributions to our unitholders and to our general partner for any one or more of the next four quarters (provided that our general partner may not establish cash reserves for distributions if the effect of the establishment of such reserves will prevent us from distributing the minimum quarterly distribution on all common units and any cumulative arrearages on such common units for the current quarter);

•	plus, if our general partner so determines, all or any portion of the cash on hand for the quarter resulting from working capital borrowings made subsequent to the end of such quarter.

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•	$60.0 million (as described below); plus

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all of our cash receipts after October 31, 2012, the closing of our initial public offering, which we refer to as our “Initial Public Offering,” excluding cash from interim capital transactions (as defined below), provided that cash receipts from the termination of a commodity hedge or interest rate hedge prior to its specified termination date shall be included in operating surplus in equal quarterly installments over the remaining scheduled life of such commodity hedge or interest rate hedge; plus

•	working capital borrowings made after the end of a quarter but on or before the date of determination of operating surplus for that quarter; plus

•

cash distributions (including incremental distributions on incentive distribution rights) paid in respect of equity issued, other than equity issued in the Initial Public Offering, to finance all or a portion of expansion capital expenditures in respect of the period from the date that we enter into a binding obligation to commence the construction, development, replacement, improvement or expansion of a capital asset and ending on the earlier to occur of the date the capital asset commences commercial service and the date that it is abandoned or disposed of; less

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•	all of our operating expenditures (as defined below) after the closing of the Initial Public Offering; less

•	the amount of cash reserves established by our general partner to provide funds for future operating expenditures; less

•	all working capital borrowings not repaid within twelve months after having been incurred, or repaid within such 12-month period with the proceeds of additional working capital borrowings.

•	repayments of working capital borrowings where such borrowings have previously been deemed to have been repaid (as described above);

•	payments (including prepayments and prepayment penalties) of principal of and premium on indebtedness other than working capital borrowings;

•	expansion capital expenditures;

•	payment of transaction expenses (including taxes) relating to interim capital transactions;

•	distributions to our partners;

•	repurchases of partnership interests (excluding repurchases we make to satisfy obligations under employee benefit plans); or

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•	any other expenditures or payments using the proceeds of the Initial Public Offering or subsequent offerings that are described in the “Use of Proceeds” section of the prospectus relating to the Initial Public Offering or such subsequent offerings.

•	borrowings other than working capital borrowings;

•	sales of our equity and debt securities;

•	sales or other dispositions of assets, other than inventory, accounts receivable and other assets sold in the ordinary course of business or as part of ordinary course retirement or replacement of assets; and

•	capital contributions received.

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•	operating surplus generated with respect to that period (excluding any amount attributable to the item described in the first bullet of the definition of operating surplus); less

•	any net increase in working capital borrowings with respect to that period; less

•	any net decrease in cash reserves for operating expenditures with respect to that period not relating to an operating expenditure made with respect to that period; plus

•	any net decrease in working capital borrowings with respect to that period; plus

•	any net decrease made in subsequent periods to cash reserves for operating expenditures initially established with respect to that period to the extent such decrease results in a reduction in adjusted operating surplus in subsequent periods; plus

•	any net increase in cash reserves for operating expenditures with respect to that period required by any debt instrument for the repayment of principal, interest or premium.

•	first, 98.0% to all common unitholders and Class A unitholders, pro rata (except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash), and 2.0% to our general partner, until we distribute for each outstanding unit an amount equal to the minimum quarterly distribution for that quarter; and

•	thereafter, in the manner described in “—General Partner Interest and Incentive Distribution Rights.”

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•	first, 98.0% to all common unitholders and Class A unitholders, pro rata (except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash), and 2.0% to our general partner, until each common unitholder receives a total of $0.301875 per unit for that quarter, which we refer to as the “first target distribution;”

•	second, 85.0% to all common unitholders and Class A unitholders, pro rata (except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash), and 15.0% to our general partner, until each common unitholder receives a total of $0.328125 per unit for that quarter, which we refer to as the “second target distribution;”

•	third, 75.0% to all common unitholders and Class A unitholders, pro rata (except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash), and 25.0% to our general partner, until each common unitholder receives a total of $0.393750 per unit for that quarter, which we refer to as the “third target distribution;” and

•	thereafter, 50.0% to all common unitholders and Class A unitholders, pro rata (except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash), and 50.0% to our general partner.

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(1)	Includes common unitholders and Class A unitholders on a pro rata basis except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash.

(2)	For so long as the Class A units are held by a wholly-owned subsidiary of MPLX, the distributions paid to the Class A unitholders will not reduce the amount of distributions paid to common unitholders and are not taken into account in calculating the general partner’s 2.0% general partner interest in quarterly distributions or incentive distribution rights.

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•	first, 98.0% to all common unitholders and Class A unitholders, pro rata (except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash), and 2.0% to our general partner, until each common unitholder receives an amount equal to 115.0% of the reset minimum quarterly distribution for that quarter;

•	second, 85.0% to all common unitholders and Class A unitholders, pro rata (except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash), and 15.0% to our general partner, until each common unitholder receives an amount per unit equal to 125.0% of the reset minimum quarterly distribution for the quarter;

•	third, 75.0% to all common unitholders and Class A unitholders, pro rata (except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash), and 25.0% to our general partner, until each common unitholder receives an amount per unit equal to 150.0% of the reset minimum quarterly distribution for the quarter; and

•	thereafter, 50.0% to all common unitholders and Class A unitholders, pro rata (except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash), and 50.0% to our general partner.

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(1)	Includes common unitholders and Class A unitholders on a pro rata basis except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash.

(2)	For so long as the Class A units are held by a wholly-owned subsidiary of MPLX, the distributions paid to the Class A unitholders will not reduce the amount of distributions paid to common unitholders and are not taken into account in calculating the general partner’s 2.0% general partner interest in quarterly distributions or incentive distribution rights.

(3)	This amount is 115.0% of the hypothetical reset minimum quarterly distribution.

(4)	This amount is 125.0% of the hypothetical reset minimum quarterly distribution.

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first, 98.0% to all common unitholders and Class A unitholders, pro rata (except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash), and 2.0% to our general partner, until we distribute for each common unit that was issued in the Initial Public Offering an amount of available cash from capital surplus equal to the Initial Public Offering price;

•

second, 98.0% to all common unitholders and Class A unitholders, pro rata (except that Class A unitholders will not be entitled to participate in any distributions of Hydrocarbon Available Cash), and 2.0% to our general partner, until we distribute for each common unit an amount of available cash from capital surplus equal to any unpaid arrearages in payment of the minimum quarterly distribution on the outstanding common units; and

•	thereafter, as if they were from operating surplus.

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•	the minimum quarterly distribution;

•	target distribution levels;

•	the unrecovered initial unit price;

•	the number of general partner units comprising the general partner interest; and

•	the arrearages in payment of the minimum quarterly distribution on the common units.

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•	first, to our general partner to the extent of any negative balance in its capital account;

•	second, to the Series A Preferred unitholders pro rata, until the capital account for each Series A Preferred unitholder is equal to the issue price of $32.50 per Series A Preferred unit;

•	third, 98.0% to all unitholders (other than the Series A Preferred unitholders) pro rata, and 2.0% to our general partner, until the capital account for each common unit is equal to the sum of:

(1)	the unrecovered initial unit price; and

(2)	the amount of the minimum quarterly distribution for the quarter during which our liquidation occurs;

•	fourth, 98.0% to all unitholders (other than the Series A Preferred unitholders), pro rata, and 2.0% to our general partner, until we allocate under this paragraph an amount per unit equal to:

(1)	the sum of the excess of the first target distribution per unit over the minimum quarterly distribution per unit for each quarter of our existence; less

(2)	the cumulative amount per unit of any distributions of available cash from operating surplus in excess of the minimum quarterly distribution per unit that we distributed 98.0% to the unitholders, pro rata, and 2.0% to our general partner, for each quarter of our existence;

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•	fifth, 85.0% to all unitholders (other than the Series A Preferred unitholders), pro rata, and 15.0% to our general partner, until we allocate under this paragraph an amount per unit equal to:

(1)	the sum of the excess of the second target distribution per unit over the first target distribution per unit for each quarter of our existence; less

(2)	the cumulative amount per unit of any distributions of available cash from operating surplus in excess of the first target distribution per unit that we distributed 85.0% to the unitholders, pro rata, and 15.0% to our general partner for each quarter of our existence;

•	sixth, 75.0% to all unitholders (other than the Series A Preferred unitholders), pro rata, and 25.0% to our general partner, until we allocate under this paragraph an amount per unit equal to:

(1)	the sum of the excess of the third target distribution per unit over the second target distribution per unit for each quarter of our existence; less

(2)	the cumulative amount per unit of any distributions of available cash from operating surplus in excess of the second target distribution per unit that we distributed 75.0% to the unitholders, pro rata, and 25.0% to our general partner for each quarter of our existence;

•	thereafter, 50.0% to all unitholders (other than the Series A Preferred unitholders), pro rata, and 50.0% to our general partner.

•	first, 98.0% to all unitholders (other than the Series A Preferred unitholders) in proportion to the positive balances in their capital accounts and 2.0% to our general partner, until the capital accounts of all unitholders have been reduced to zero;

•	second, to the Series A Preferred unitholders, to the extent of and in proportion to the positive balances in their capital accounts; and

•	thereafter, 100.0% to our general partner.

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•	with regard to distributions of available cash, please read “Provisions of Our Partnership Agreement Relating to Cash Distributions;”

•	with regard to the transfer of common units, please read “Description of Capitalization—Transfer of Units;” and

•	with regard to allocations of taxable income and taxable loss, please read “Material Federal Income Tax Consequences.”

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•	to remove or replace our general partner;

•	to approve some amendments to the Partnership Agreement; or

•	to take other action under the Partnership Agreement;

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•	enlarge the obligations of any limited partner without its consent, unless such is deemed to have occurred as a result of an amendment approved by at least a majority of the type or class of limited partner interests so affected; or

•	enlarge the obligations of, restrict in any way any action by or rights of, or reduce in any way the amounts distributable, reimbursable or otherwise payable by us to our general partner or any of its affiliates without its consent, which consent may be given or withheld at its option.

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•	a change in our name, the location of our principal office, our registered agent or our registered office;

•	the admission, substitution, withdrawal or removal of partners in accordance with the Partnership Agreement;

•

a change that our general partner determines to be necessary or appropriate to qualify or continue our qualification as a limited partnership or a partnership in which the limited partners have limited liability under the laws of any state or to ensure that neither we nor any of our subsidiaries will be treated as an association taxable as a corporation or otherwise taxed as an entity for federal income tax purposes;

•

an amendment that is necessary, in the opinion of our counsel, to prevent us or our general partner or its directors, officers, agents or trustees, from in any manner, being subjected to the provisions of the Investment Company Act of 1940, the Investment Advisors Act of 1940, or “plan asset” regulations adopted under the Employee Retirement Income Security Act of 1974 (ERISA), whether or not substantially similar to plan asset regulations currently applied or proposed by the United States Department of Labor;

•	an amendment that our general partner determines to be necessary or appropriate for the authorization or issuance of additional partnership interests;

•	any amendment expressly permitted in the Partnership Agreement to be made by our general partner acting alone;

•	an amendment effected, necessitated or contemplated by a merger agreement that has been approved under the terms of the Partnership Agreement;

•	any amendment that our general partner determines to be necessary or appropriate to reflect and account for the formation by us of, or our investment in, any corporation, partnership or other entity, in connection with our conduct of activities permitted by the Partnership Agreement;

•	a change in our fiscal year or taxable year and any other changes that our general partner determines to be necessary or appropriate as a result of such change;

•	mergers with, conveyances to or conversions into another limited liability entity that is newly formed and has no assets, liabilities or operations at the time of the merger, conveyance or conversion other than those it receives by way of the merger, conveyance or conversion; or

•	any other amendments substantially similar to any of the matters described in the clauses above.

•	do not adversely affect in any material respect the limited partners considered as a whole or any particular class of partnership interests as compared to other classes of partnership interests;

•	are necessary or appropriate to satisfy any requirements, conditions or guidelines contained in any opinion, directive, order, ruling or regulation of any federal or state agency or judicial authority or contained in any federal or state statute;

•	are necessary or appropriate to facilitate the trading of limited partner interests or to comply with any rule, regulation, guideline or requirement of any securities exchange on which the limited partner interests are or will be listed or admitted to trading;

•	are necessary or appropriate for any action taken by our general partner relating to splits or combinations of units under the provisions of the Partnership Agreement; or

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•	are required to effect the intent expressed in this prospectus or the intent of the provisions of the Partnership Agreement or are otherwise contemplated by the Partnership Agreement.

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•	the withdrawal or removal of our general partner or any other event that results in its ceasing to be our general partner other than by reason of a transfer of its general partner interest in accordance with the Partnership Agreement or withdrawal or removal followed by approval and admission of a successor;

•	the election of our general partner to dissolve us, if approved by the holders of units representing a unit majority;

•	the entry of a decree of judicial dissolution of our partnership; or

•	there being no limited partners, unless we are continued without dissolution in accordance with the Delaware Act.

•	the action would not result in the loss of limited liability of any limited partner; and

•	neither our partnership nor any of our subsidiaries would be treated as an association taxable as a corporation or otherwise be taxable as an entity for federal income tax purposes upon the exercise of that right to continue.

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•	the highest cash price paid by either our general partner or any of its affiliates for any limited partner interests of the class purchased within the 90 days preceding the date on which our general partner first mails notice of its election to purchase those limited partner interests; and

•	the current market price calculated in accordance with the Partnership Agreement as of the date three business days before the date the notice is mailed.

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•	that the transferee or unitholder is an individual or an entity subject to United States federal income taxation on the income generated by us; or

•	that, if the transferee unitholder is an entity not subject to United States federal income taxation on the income generated by us, as in the case, for example, of a mutual fund taxed as a regulated investment company or a partnership, all the entity’s owners are subject to United States federal income taxation on the income generated by us.

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•	our general partner;

•	any departing general partner;

•	any person who is or was an affiliate of our general partner or any departing general partner;

•	any person who is or was a director, officer, managing member, manager, general partner, fiduciary or trustee of us or our subsidiaries, or any entity set forth in the preceding three bullet points;

•	any person who is or was serving as director, officer, managing member, manager, general partner, fiduciary or trustee of another person owing a fiduciary duty to us or any of our subsidiaries at the request of our general partner or any departing general partner or any of their affiliates; and

•	any person designated by our general partner because such person’s status, service or relationship expose such person to claims or suits relating to our business and affairs.

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•	a current list of the name and last known address of each record holder;

•	copies of the Partnership Agreement and our certificate of limited partnership and all amendments thereto; and

•	certain information regarding the status of our business and financial condition.

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•	We will be classified as a partnership for federal income tax purposes; and

•	Each of our operating subsidiaries, except for MarkWest Hydrocarbon, will be treated as a partnership or will be disregarded as an entity separate from us for federal income tax purposes.

•	Neither we nor any of the operating subsidiaries has elected or will elect to be treated as a corporation; and

•	For each taxable year, more than 90.0% of our gross income has been and will be income of the type that Jones Day has opined or will opine is “qualifying income” within the meaning of Section 7704(d) of the Internal Revenue Code.

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•	interest on indebtedness properly allocable to property held for investment;

•	our interest expense attributed to portfolio income; and

•	the portion of interest expense incurred to purchase or carry an interest in a passive activity to the extent attributable to portfolio income.

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•	his or her relative contributions to us;

•	the interests of all the partners in profits and losses;

•	the interest of all the partners in cash flow; and

•	the rights of all the partners to distributions of capital upon liquidation.

•	any of our income, gain, loss or deduction with respect to those units would not be reportable by the common unitholder;

•	any cash distributions received by the common unitholder as to those units would be fully taxable; and

•	while not entirely free from doubt, all of these distributions would appear to be ordinary income.

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•	a short sale;

•	an offsetting notional principal contract; or

•	a futures or forward contract;

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•	the name, address and taxpayer identification number of the beneficial owner and the nominee;

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•	information about whether the beneficial owner is:

•	a person that is not a U.S. person;

•	a foreign government, an international organization or any wholly owned agency or instrumentality of either of the foregoing; or

•	a tax-exempt entity;

•	the amount and description of units held, acquired or transferred for the beneficial owner; and

•	specific information including the dates of acquisitions and transfers, means of acquisitions and transfers, and acquisition cost for purchases, as well as the amount of net proceeds from dispositions.

•	for which there is, or was, “substantial authority”; or

•	as to which there is a reasonable basis and the pertinent facts of that position are disclosed on the tax return.

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•	accuracy-related penalties with a broader scope, significantly narrower exceptions, and potentially greater amounts than described above at “—Administrative Matters—Accuracy-Related Penalties”;

•	for those persons otherwise entitled to deduct interest on federal tax deficiencies, nondeductibility of interest on any resulting tax liability; and

•	in the case of a listed transaction, an extended statute of limitations.

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•	whether the investment is prudent under Section 404(a)(1)(B) of ERISA or any other applicable Similar Laws;

•	whether in making the investment, the plan will satisfy the diversification requirements of Section 404(a)(1)(C) of ERISA or any other applicable Similar Laws;

•	whether the investment will result in recognition of unrelated business taxable income by the plan and, if so, the potential after-tax investment return. Please read “Material Federal Income Tax Consequences—Tax-Exempt Organizations and Other Investors”; and

•	whether making such an investment will comply with the delegation of control and prohibited transaction provisions of ERISA and the Internal Revenue Code or any other applicable Similar Laws.

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•	fixed prices;

•	market prices prevailing at the time of any sale under this registration statement;

•	prices related to market prices;

•	varying prices determined at the time of sale; or

•	negotiated prices.

•	in or through one or more distributions;

•	on the New York Stock Exchange;

•	in the over-the-counter market; or

•	in privately negotiated transactions.

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*	Estimated expenses are not presently known. The foregoing sets forth the general categories of expenses that MPLX anticipates it will incur in connection with the offering of securities under this Registration Statement. An estimate of the aggregate expenses in connection with the issuance and distribution of the securities being offered may be included in an applicable prospectus supplement.

•	MPLX GP LLC, as the general partner of MPLX;

•	any departing general partner of MPLX;

•	any person who is or was an affiliate of the MPLX GP LLC or any departing general partner of MPLX;

•	any person who is or was a managing member, manager, general partner, director, officer, fiduciary or trustee of MPLX, its subsidiaries, MPLX GP LLC, any departing general partner of MPLX or any of their respective affiliates;

•

any person who is or was serving at the request of MPLX GP LLC or any departing general partner of MPLX or any of their respective affiliates as an officer, director, managing member, manager, general partner, fiduciary or trustee of another person owing a fiduciary duty to MPLX or any of its subsidiaries, provided that a person shall not be an Indemnitee for purposes of the Partnership Agreement by reason of providing, on a fee-for-services basis, trustee, fiduciary or custodial services; and

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•	any person MPLX GP LLC designates as an Indemnitee because such person’s status, service or relationship exposes such person to claims or suits relating to the business and affairs of MPLX and its subsidiaries.

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(a)	The undersigned Registrant hereby undertakes:

(1)	To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i)	To include any prospectus required by Section 10(a)(3) of the Securities Act;

(ii)

To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii)	To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

(2)	That, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3)	To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4)	That, for the purpose of determining liability under the Securities Act to any purchaser:

(i)	Each prospectus filed by the Registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(ii)

Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii) or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement

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(b)

The undersigned Registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the Registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to section 15(d) of the Exchange Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(c)

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the Registrant pursuant to the foregoing provisions, or otherwise, the Registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by a director, officer or controlling person of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

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*	The undersigned by signing his name hereto does sign and execute this registration statement on Form S-3 pursuant to the Powers of Attorney executed by the above-named directors and officers of the registrant, which are being filed herewith on behalf of such directors and officers.

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