MPLX LP : 3Q 2020 Earnings Release Slides–November 2, 2020

Forward‐Looking Statements

This presentation contains forward-looking statements within the meaning of federal securities laws regarding MPLX LP (MPLX). These forward-looking statements relate to, among other things, MPLX's expectations, estimates and projections concerning the business and operations, financial priorities and strategic plans of MPLX. These statements are accompanied by cautionary language identifying important factors, though not necessarily all such factors, that could cause future outcomes to differ materially from those set forth in the forward-looking statements. You can identify forward-looking statements by words such as "anticipate," "believe," "commitment," "could," "design," "estimate," "expect," "forecast," "goal," "guidance," "imply," "intend," "may," "objective," "opportunity," "outlook," "plan," "policy," "position," "potential," "predict," "priority," "project," "proposition," "prospective," "pursue," "seek," "should," "strategy," "target," "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 company's 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 but are not limited to: the effects of the recent outbreak of COVID-19, including any related government policies and actions, and the adverse impact thereof on our business, financial condition, results of operations and cash flows, including, but not limited to, our growth, operating costs, labor availability, logistical capabilities, customer demand for our services and industry demand generally, cash position, taxes, the price of our securities and trading markets with respect thereto, our ability to access capital markets, and the global economy and financial markets generally; the ability to reduce capital and operating expenses; the risk of further impairments; the risk that anticipated opportunities and any other synergies from or benefits of the Andeavor Logistics LP (ANDX) acquisition may not be fully realized or may take longer to realize than expected, including whether the transaction will be accretive within the expected timeframe or at all; disruption from the transaction making it more difficult to maintain relationships with customers, employees or suppliers; risks relating to any unforeseen liabilities of ANDX; the amount and timing of future distributions; negative capital market conditions, including an increase of the current yield on common units; the ability to achieve strategic and financial objectives, including positive free cash flow in 2021, and with respect to distribution coverage, future distribution levels, proposed projects and completed transactions; the success of Marathon Petroleum Corporation's (MPC) portfolio optimization, including the ability to complete any divestitures on commercially reasonable terms and/or within the expected timeframe, and the effects of any such divestitures on the business, financial condition, results of operations and cash flows; adverse changes in laws including with respect to tax and regulatory matters; the adequacy of capital resources and liquidity, including, but not limited to, availability of sufficient cash flow to pay distributions and access to debt on commercially reasonable terms, and the ability to successfully execute business plans, growth strategies and self-funding models and to effect any common unit repurchases; 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 as a result of the COVID-19 pandemic (including any related government policies and actions), other infectious disease outbreaks, natural hazards, extreme weather events or otherwise; non-payment or non-performance by our producer and other customers; changes to the expected construction costs and timing of projects and planned investments, and the ability to obtain regulatory and other approvals with respect thereto; 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 financial policies, capital budgets, and earnings and distributions; the ability to manage disruptions in credit markets or changes to credit ratings; compliance with federal and state environmental, economic, health and safety, energy and other policies and regulations and/or enforcement actions initiated thereunder; adverse results in litigation; other risk factors inherent to MPLX's industry; risks related to MPC; 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, 2019, and in Forms 10-Q and other filings, filed with 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 but are not limited to: the effects of the recent outbreak of COVID-19, including any related government policies and actions, and the adverse impact thereof on the business, financial condition, results of operations and cash flows, including, but not limited to, growth, operating costs, labor availability, logistical capabilities, customer demand for products and industry demand generally, margins, inventory value, cash position, taxes, the price of securities and trading markets with respect thereto, the ability to access capital markets, and the global economy and financial markets generally; the effects of the recent outbreak of COVID-19, and the current economic environment generally, on working capital, cash flows and liquidity, which can be significantly affected by decreases in commodity prices; the ability to reduce capital and operating expenses; with respect to the proposed sale of Speedway, the ability to successfully complete the sale within the expected timeframe, on the expected terms, or at all, based on numerous factors, including the failure to satisfy any of the conditions to the consummation of the proposed transaction (including obtaining certain governmental or regulatory approvals on the proposed terms and schedule), the occurrence of any event, change or other circumstance that could give rise to the termination of the proposed transaction; MPC's ability to utilize the proceeds as anticipated; the risk that the dissynergy costs, costs of restructuring transactions and other costs incurred in connection with the proposed transaction will exceed our estimates; and our ability to capture value and realize the other expected benefits from the associated ongoing supply relationship following consummation of the proposed sale; the risk that the cost savings and any other synergies from MPC's acquisition of Andeavor and the ANDX acquisition may not be fully realized or may take longer to realize than expected, including whether the ANDX transaction will be accretive within the expected timeframe or at all; disruption from the Andeavor or ANDX transactions making it more difficult to maintain relationships with customers, employees or suppliers; risks relating to any unforeseen liabilities of Andeavor or ANDX, respectively; the risk of further impairments; the ability to complete any divestitures on commercially reasonable terms and/or within the expected timeframe, and the effects of any such divestitures on the business, financial condition, results of operations and cash flows; future levels of revenues, refining and marketing margins, operating costs, gasoline and distillate margins, merchandise margins, income from operations, net income and earnings per share; the regional, national and worldwide availability and pricing of refined products, crude oil, natural gas, NGLs and other feedstocks; consumer demand for refined products; the ability to manage disruptions in credit markets or changes to credit ratings; future levels of capital, environmental and maintenance expenditures; general and administrative and other expenses; the success or timing of completion of ongoing or anticipated capital or maintenance projects, including the potential conversion of MPC's Martinez Refinery to a renewable diesel facility; the receipt of relevant third party and/or regulatory approvals; the reliability of processing units and other equipment; the successful realization of business strategies, growth opportunities and expected investment; share repurchase authorizations, including the timing and amounts of such repurchases; the adequacy of capital resources and liquidity, including availability, timing and amounts of free cash flow necessary to execute business plans, complete announced capital projects and to effect any share repurchases or to maintain or increase the dividend; the effect of restructuring or reorganization of business components, including those undertaken in connection with the Speedway sale and workforce reduction; the potential effects of judicial or other proceedings, including remedial actions involving removal and reclamation obligations under environmental regulations, on the business, financial condition, results of operations and cash flows; continued or further volatility in and/or degradation of general economic, market, industry or business conditions as a result of the COVID-19 pandemic (including any related government policies and actions), other infectious disease outbreaks, natural hazards, extreme weather events or otherwise; general economic, political or regulatory developments, including changes in governmental policies relating to refined petroleum products, crude oil, natural gas or NGLs, regulation or taxation and other economic and political developments (including those caused by public health issues and outbreaks); non-payment or non-performance by producer and other customers; compliance with federal and state environmental, economic, health and safety, energy and other policies, permitting and regulations, including the cost of compliance with the Renewable Fuel Standard, and/or enforcement actions initiated thereunder; the effects of actions of third parties such as competitors, activist investors or federal, foreign, state or local regulatory authorities or plaintiffs in litigation; the impact of adverse market conditions or other similar risks to those identified herein affecting MPLX; 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, 2019, and in Forms 10-Q and other filings, filed with the SEC.

We have based our forward-looking statements on our current expectations, estimates and projections about our business and industry. We caution that these statements are not guarantees of future performance and you should not rely unduly on them, as they involve risks, uncertainties, and assumptions that we cannot predict. In addition, we have based many of these forward-looking statements on assumptions about future events that may prove to be inaccurate. While our management considers these assumptions to be reasonable, they are inherently subject to significant business, economic, competitive, regulatory and other risks, contingencies and uncertainties, most of which are difficult to predict and many of which are beyond our control. Accordingly, our actual results may differ materially from the future performance that we have expressed or forecast in our forward-looking statements. Any forward-looking statements speak only as of the date of the applicable communication and we undertake no obligation to update any forward-looking statements except to the extent required by applicable law. Copies of MPLX's Form 10-K, Forms 10-Q and other SEC filings are available on the SEC's website, MPLX's website athttp://ir.mplx.comor by contacting MPLX's Investor Relations office. Copies of MPC's Form 10-K, Forms 10-Q and other SEC filings are available on the SEC's website, MPC's website athttps://www.marathonpetroleum.com/Investors/ or by contacting MPC's Investor Relations office.

Non-GAAP Financial Measures

Adjusted EBITDA, distributable cash flow (DCF), distribution coverage ratio and leverage ratio are non-GAAP financial measures provided in this presentation. Adjusted EBITDA and DCF reconciliations to the nearest GAAP financial measures are included in the Appendix to this presentation. Distribution coverage ratio is the ratio of DCF attributable to GP and LP unitholders to total GP and LP distributions declared. Leverage ratio is consolidated debt to last twelve months pro forma adjusted EBITDA. These non-GAAP financial measures are not defined by GAAP and should not be considered in isolation or as an alternative to net income attributable to MPLX, net cash provided by operating activities or other financial measures prepared in accordance with GAAP. Certain EBITDA forecasts were determined on an EBITDA-only basis. Accordingly, information related to the elements of net income, including tax and interest, are not available and, therefore, reconciliations of these forward-looking non-GAAP financial measures to the nearest GAAP financial measures have not been provided.

Stable Cash Flows

⚫ Stable, fee based cash flows with minimum volume commitments

• ⚫ On-track to reduce 2020 forecasted operating expenses by $200 million

• ⚫ Supports goal of achieving positive free cash flow for 2021

• ⚫ Announced Board authorization of a unit repurchase program for up to $1 billion of common units held by the public

Historical Quarterly Adjusted EBITDA

($ Billions)

4Q 2019

1Q 2020

MPLX L&S

2Q 2020

MPLX G&P

3Q 2020

Continued Capital Discipline

⚫ On-track to achieve forecasted 2020 reduction targets:

• - Reducing net maintenance capital spending by $100 million to approximately $150 million

• - Reducing growth capital(a) spending by over $600 million to approximately $900 million

⚫ Continued focus on L&S investments

2018

Growth Capital(b)

$2.6 B

2019

2020 Target

L&S GrowthG&P Growth

• (a) Adjusted Growth Capital spending and Net Maintenance Capital spending. See appendix for additional information and reconciliations

• (b) Excludes Net Maintenance Capital