MPLX LP Announces Closing of $1 Billion Private Placement of 6.5% Series A Convertible Preferred Units

FINDLAY, Ohio, May 13, 2016 - MPLX LP (NYSE: MPLX) has closed the previously announced sale of approximately 30.8 million Series A Convertible Preferred Units representing limited partnership interests in the Partnership (the "Preferred Units").  Primary investors include funds managed by Stonepeak Infrastructure Partners, Magnetar Capital, Kayne Anderson Capital Advisors and The Energy & Minerals Group.  The aggregate net proceeds of approximately $984 million from the sale of these Preferred Units will be used for capital expenditures, repayment of debt, and general partnership purposes.  MPLX previously announced that the combination of some opportunistic equity issuances in the first quarter and this private placement provides for the partnership's anticipated funding needs for the remainder of 2016 and into 2017.

The securities offered in the private placement have not been registered under the Securities Act of 1933, as amended (the "Securities Act"), or any state securities laws and may not be offered or sold in the United States absent registration or an applicable exemption from registration requirements of the Securities Act and applicable state laws.

This press release is neither an offer to sell nor a solicitation of an offer to purchase the securities described herein.

###

About MPLX LP
MPLX is a diversified, growth-oriented master limited partnership formed in 2012 by Marathon Petroleum Corporation to own, operate, develop and acquire midstream energy infrastructure assets. We are engaged in the gathering, processing and transportation of natural gas; the gathering, transportation, fractionation, storage and marketing of NGLs; and the transportation and storage of crude oil and refined petroleum products. Headquartered in Findlay, Ohio, MPLX's assets consist of a network of common carrier crude oil and products pipeline assets located in the Midwest and Gulf Coast regions of the United States, an inland marine business, a butane storage cavern located in West Virginia with approximately 1 million barrels of storage capacity, crude oil and product storage facilities (tank farms) with approximately 4.5 million barrels of available storage capacity, a barge dock facility with approximately 78,000 barrels per day of crude oil and product throughput capacity and gathering and processing assets that include more than 5,000 miles of gas gathering and NGL pipelines, 53 gas processing plants, 13 NGL fractionation facilities and one condensate stabilization facility.

Investor Relations Contacts:
Lisa D. Wilson (419) 421-2071
Kevin Hawkins (866) 858-0482

Media Contact:
Chuck Rice (419) 421-2521
Jamal Kheiry (419) 421-3312

Forward-looking statements
This press release contains forward-looking statements within the meaning of federal securities laws regarding MPLX LP ("MPLX") and Marathon Petroleum Corporation ("MPC").These forward-looking statements relate to, among other things, expectations, estimates and projections concerning the business and operations of MPLX and MPC. You can identify forward-looking statements by words such as "anticipate," "believe," "design," "estimate," "expect," "forecast," "goal," "guidance," "imply," "intend," "objective," "opportunity," "outlook," "plan," "position," "pursue," "prospective," "predict," "project," "potential," "seek," "strategy," "target," "could," "may," "should," "would," "will" or other similar expressions that convey the uncertainty of future events or outcomes. Such forward-looking statements are not guarantees of future performance and are subject to risks, uncertainties and other factors, some of which are beyond the companies' control and are difficult to predict. Factors that could cause MPLX's actual results to differ materially from those implied in the forward-looking statements include: negative capital market conditions, including a persistence or increase of the current yield on common units, which is higher than historical yields, adversely affecting MPLX's ability to meet its distribution growth guidance; risk that the synergies from the acquisition of MarkWest Energy Partners, L.P. ("MarkWest") by MPLX may not be fully realized or may take longer to realize than expected; disruption from the MPLX/MarkWest merger making it more difficult to maintain relationships with customers, employees or suppliers; risks relating to any unforeseen liabilities of MarkWest; the adequacy of MPLX's capital resources and liquidity, including, but not limited to, availability of sufficient cash flow to pay distributions, and the ability to successfully execute its business plans and growth strategy; the timing and extent of changes in commodity prices and demand for crude oil, refined products, feedstocks or other hydrocarbon-based products; continued/further volatility in and/or degradation of market and industry conditions; completion of midstream infrastructure by competitors; disruptions due to equipment interruption or failure, including electrical shortages and power grid failures; the suspension, reduction or termination of MPC's obligations under MPLX's commercial agreements; modifications to earnings and distribution growth objectives; the level of support from MPC, including drop-downs, alternative financing arrangements, taking equity units, and other methods of sponsor support, as a result of the capital allocation needs of the enterprise as a whole and its ability to provide support on commercially reasonable terms; federal and state environmental, economic, health and safety, energy and other policies and regulations; changes to MPLX's capital budget; other risk factors inherent to MPLX's industry; and the factors set forth under the heading "Risk Factors" in MPLX's Annual Report on Form 10-K for the year ended Dec. 31, 2015, filed with the Securities and Exchange Commission (SEC). Factors that could cause MPC's actual results to differ materially from those implied in the forward-looking statements include: risks described above relating to MPLX and the MPLX/MarkWest merger; changes to the expected construction costs and timing of pipeline projects; continued/further volatility in and/or degradation of market and industry conditions; the availability and pricing of crude oil and other feedstocks; slower growth in domestic and Canadian crude supply; the effects of the lifting of the U.S. crude oil export ban; completion of pipeline capacity to areas outside the U.S. Midwest; consumer demand for refined products; transportation logistics; the reliability of processing units and other equipment; MPC's ability to successfully implement growth opportunities; modifications to MPLX earnings and distribution growth objectives; federal and state environmental, economic, health and safety, energy and other policies and regulations, including the cost of compliance with the Renewable Fuel Standard; changes to MPC's capital budget; other risk factors inherent to MPC's industry; and the factors set forth under the heading "Risk Factors" in MPC's Annual Report on Form 10-K for the year ended Dec. 31, 2015, filed with the SEC. In addition, the forward-looking statements included herein could be affected by general domestic and international economic and political conditions. Unpredictable or unknown factors not discussed here, in MPLX's Form 10-K or in MPC's Form 10-K could also have material adverse effects on forward-looking statements. Copies of MPLX's Form 10-K are available on the SEC website, MPLX's website at http://ir.mplx.com or by contacting MPLX's Investor Relations office. Copies of MPC's Form 10-K are available on the SEC website, MPC's website at http://ir.marathonpetroleum.com or by contacting MPC's Investor Relations office.