2020 ANNUAL REPORT SHERWOOD, WEST VIRGINIA MPLX I 2020 ANNUAL REPORT FROM THE CHAIRMAN, PRESIDENT AND CEO Fellow Unitholders, an MPLX joint venture that is connected to nearly 20 gas processing plants in the Delaware Basin of far West Texas and More than any other year, 2020 highlighted the strength, stability southeastern New Mexico. The system entered commercial and resiliency of our underlying businesses, with the company service earlier in 2021. Through another project, we increased achieving several significant milestones despite the unprecedented challenges and disruptions created by the global COVID-19 fractionation capacity at our Hopedale facility in Ohio. The pandemic. We generated positive excess cash flow for the full 80,000 barrel-per-day expansion has allowed the facility to year after self-funding our total capital investments and our reach record fractionation volumes of 320,000 barrels per day. distributions to unitholders, and we achieved this sooner than We also continued to advance the Smithburg 1 Processing our original target of 2021. This accomplishment provided us the Plant project, which will add 200 million cubic feet per day of financial flexibility to begin implementing a board-authorized natural gas processing capacity for the Marcellus Basin when repurchase program of up to $1 billion in outstanding publicly traded it comes online in 2021. common units, and we completed the repurchase of approximately During 2021, we intend to continue exercising strict capital $33 million in units during the fourth quarter of 2020. discipline with a growth capital outlook of $800 million, focusing In addition, we were able to increase our adjusted EBITDA (a) for on projects expected to deliver the highest returns and support the year by $100 million to $5.2 billion and grow total distributable the generation of excess cash flow. cash flow compared to 2019, allowing us to return more than Focusing on a Sustainable Future $3 billion in capital to unitholders. We also took critical steps to strengthen our financial foundation, including: We also recognize the importance of setting objectives that • Reducing our forecasted operating expenses for 2020 by drive continuous improvement in our Environmental, Social and more than $200 million; Governance performance, and we believe we are positioning • Reducing our 2020 capital spend by more than $700 million MPLX to be an industry leader in this space. From lowering the from the target level; and carbon intensity of our operations to improving energy efficiency • Executing other steps to further enhance our long-term cost and conserving natural resources, we are challenging ourselves structure, drive efficiencies in our business, and optimize our to lead in sustainable energy and to embed sustainability portfolio to focus on assets with long-term strategic value as throughout our decision-making processes. the U.S. energy landscape evolves. Specifically in 2020, we voluntarily created a target for our G&P Strategic Organic Growth segment to reduce methane emissions intensity 50% below 2016 levels by 2025. MPLX also earned four EPA ENERGY STAR® During 2020, we also made important progress on key growth Challenge for Industry Awards for energy efficiency and received projects in our Logistics and Storage (L&S) and Gathering and the American Petroleum Institute’s Distinguished Pipeline Safety Processing (G&P) segments. Through pipeline projects expected Award. In addition, we engaged 1,450 landowners and more than to come online in 2021, we are continuing to advance our strategy 28,000 households through Marathon Pipe Line’s Earning Your of creating integrated crude oil and natural gas logistics systems Trust program. from the Permian Basin of West Texas to the U.S. Gulf Coast. Key projects in our L&S segment included the following: As we look forward in 2021, the availability of COVID-19 vaccines in the U.S. has provided hope for continued economic recovery • Segments of the Wink-to-Webster crude oil pipeline, in which MPLX has an equity interest, are expected to come online and relief from the broad-ranging uncertainties of the last year. Our throughout 2021. The pipeline will have destination points in disciplined approach to managing our business in 2020 allowed us the Houston market, with connectivity to Marathon Petroleum to not only navigate tremendous challenges, but also to accomplish Corporation’s (MPC) Galveston Bay refinery. significant short- and long-term objectives that delivered value to our unitholders and critical support to our sponsor, MPC. • The Whistler pipeline, which will carry natural gas from the Continuing this approach in the year ahead, with an Permian Basin to the Agua Dulce market in South Texas with emphasis on strict capital discipline and EBITDA industry connectivity to reach MPC’s Galveston Bay refinery, growth, supports our ongoing goal of generating is expected to go into service in the second half of 2021. excess cash flow for 2021, and ultimately, expanding MPLX also has an equity interest in this pipeline. our opportunities to return incremental capital • As part of a joint venture, MPLX is continuing to develop a to our unitholders. solution primarily utilizing existing infrastructure to create Sincerely, natural gas liquids takeaway capacity from the Permian Basin to Sweeny, Texas, to support producer customers. In our G&P segment, approximately 1.8 billion-cubic-feet-per-day of capacity was added to the Agua Blanca pipeline system, Michael J. Hennigan (a) Non-GAAP financial measure. See discussion on inside back cover of this wrap. Chairman, President and Chief Executive Officer UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2020 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ___________________ to __________________ Commission file number 001-35714 MPLX LP (Exact name of registrant as specified in its charter) Delaware 27-0005456 (State or other jurisdiction of incorporation or organization) (I.R.S. Employer Identification No.) 200 E. Hardin Street, Findlay, OH 45840-3229 (Address of principal executive offices) (Zip code) (419) 421-2414 (Registrant’s telephone number, including area code) Securities registered pursuant to Section 12(b) of the Act: Title of each class Trading Symbol(s) Name of each exchange on which registered Common Units Representing Limited Partnership Interests MPLX New York Stock Exchange Securities registered pursuant to Section 12(g) of the Act: None Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes x No ¨ Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ¨ No x Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes x No ¨ Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes x No ¨ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act. Large Accelerated Filer x Accelerated filer ¨ Non-accelerated filer ¨ Smaller reporting company ☐ Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨ Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. x Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No x The aggregate market value of common units held by non-affiliates as of June 30, 2020 was approximately $6.8 billion. This amount is based on the closing price of the registrant’s common units on the New York Stock Exchange on June 30, 2020. Common units held by executive officers and directors of the registrant and its affiliates are not included in the computation. The registrant, solely for the purpose of this required presentation, has deemed its directors and executive officers and those of its affiliates to be affiliates. MPLX LP had 1,037,169,607 common units outstanding at February 12, 2021. DOCUMENTS INCORPORATED BY REFERENCE: None Table of Contents Page PART I Item 1. Business 3 Item 1A. Risk Factors 28 Item 1B. Unresolved Staff Comments 52 Item 2. Properties 53 Item 3. Legal Proceedings 58 Item 4. Mine Safety Disclosures 60 PART II Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities 60 Item 6. Selected Financial Data 62 Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations 63 Item 7A.