Exhibit 99.1

Marathon Petroleum Corporation Reports Third-Quarter 2012 Results

FINDLAY, Ohio, Nov. 1, 2012 – Marathon Petroleum Corporation (NYSE: MPC) today reported third-quarter net income of $1,224 million, or $3.59 per diluted share, compared with net income of $1,133 million, or $3.16 per diluted share, in the third quarter of 2011. For the third quarter of 2012, net income adjusted for special items was $1,129 million, or $3.31 per diluted share, compared with net income adjusted for special items of $1,133 million, or $3.16 per diluted share, in the third quarter of 2011.

“MPC’s continued strong operating performance allowed us to leverage favorable market conditions, which led to very strong financial results during the third quarter,” said MPC President and Chief Executive Officer Gary R. Heminger. “Our focus on safe and efficient operations has allowed us to utilize our assets at optimal levels.”

Heminger said the company’s positive financial results were complemented by success in various other areas aimed at increasing future shareholder value.

“Our $2.2 billion Detroit Heavy Oil Upgrade Project is nearly complete,” Heminger said. “The Detroit refinery began its scheduled shutdown and maintenance in September, and we are now progressing toward completing the tie-in of the upgrade project with the existing refinery, with startup expected early this month.” Once the refinery is running at its new capacity of 120,000 barrels per calendar day (bpcd), the plant’s heavy crude oil processing capacity will increase from 20,000 bpcd to 100,000 bpcd.

Early in the third quarter, MPLX LP (MPLX) filed a registration statement with the U.S. Securities and Exchange Commission for an initial public offering (IPO) of common units representing limited partner interests in MPLX. MPC intends for MPLX to become its primary vehicle for ownership, operation and growth of hydrocarbon-based pipelines and other midstream assets. The IPO was priced on Oct. 25, and units are currently trading on the New York Stock Exchange under the ticker symbol “MPLX.”

In October, MPC announced that it had signed a definitive agreement to purchase BP’s 451,000 bpcd refinery in Texas City, Texas, and related assets. The acquisition is expected to close early in 2013 and be accretive to earnings in the first year of operation. “I’m proud to report that we continue executing on our commitment to balance selective investment in the business with returning capital to our shareholders,” Heminger said.

Noting the importance of safe operations to the company’s success, Heminger pointed out that MPC’s 80,000 bpcd Texas City refinery was recently certified as a Voluntary Protection Program Star Worksite by the Occupational Safety and Health Administration. That certification represents the fourth MPC refinery to meet the rigorous safety standards of the federal program. Only about one fifth of U.S. refineries have achieved this certification. “I firmly believe that our commitment to safety is one of the strongest components of our operational advantage in this very challenging industry,” said Heminger. “I’m proud of our employees’ commitment to safety and operational excellence, and I commend all our Texas City refinery personnel on this significant achievement.”

Segment Results

Total income from operations was $1,895 million in the third quarter of 2012, compared with $1,759 million in the third quarter of 2011.

Refining & Marketing

Refining & Marketing segment income from operations was $1,691 million in the third quarter of 2012, compared with $1,711 million of segment income in the third quarter of 2011. The Refining & Marketing gross margin was relatively unchanged at $13.12 per barrel in the third quarter of 2012, compared with $13.18 per barrel in the third quarter of 2011. The Chicago and U.S. Gulf Coast Light Louisiana Sweet (LLS) 6-3-2-1 blended crack spread increased to $11.81 per barrel in the third quarter of 2012 from $5.98 per barrel in the third quarter of 2011. However, MPC had higher crude oil costs in the third quarter of 2012 relative to the market-based blended crack spread, due to narrower crude oil differentials compared to the benchmark LLS. In addition, MPC

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had higher planned turnaround and major maintenance expenses in the third quarter of 2012 compared to the same period in 2011.

Speedway

Speedway segment income from operations was $76 million in the third quarter of 2012, compared with $85 million in the third quarter of 2011. The $9 million decrease was primarily the result of a lower gasoline and distillates gross margin and higher expenses, partially offset by an increase in merchandise gross margin. Speedway gasoline and distillates gross margin per gallon averaged 11 cents in the third quarter of 2012, compared with 12.57 cents in the third quarter of 2011.

Speedway same-store merchandise sales decreased 0.8 percent in the third quarter of 2012, compared with a 1.8 percent increase in the third quarter of 2011. Same-store gasoline sales volume decreased 3.9 percent in the third quarter of 2012, compared with a decrease of 1.6 percent in the third quarter of 2011.

Pipeline Transportation

Pipeline Transportation segment income from operations was $52 million in the third quarter of 2012, compared with $56 million in the third quarter of 2011. The decrease in segment income was primarily due to a decrease in pipeline affiliate income.

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Corporate and Special Items

Corporate and other unallocated expenses decreased $19 million in the third quarter of 2012 compared to the third quarter of 2011. The decrease was primarily due to a decrease in pension expenses associated with a pension plan amendment announced in the second quarter of 2012.

During the third quarter of 2012, MPC recognized a pretax gain of $183 million resulting from the sale of the company’s Minnesota assets in 2010. MPC also recorded pretax pension settlement expenses of $33 million, resulting from the level of employee lump-sum retirement distributions occurring in the third quarter of 2012.

Strong Financial Position and Liquidity

On Sept. 30, 2012, the company had $3.4 billion in cash and cash equivalents, an unused $2 billion revolving credit agreement and a $1 billion unused trade receivables securitization facility. The company’s credit facilities and cash position should provide the company with sufficient flexibility to meet its day-to-day operational needs and continue its balanced approach to investing in the business and returning capital to shareholders. As of Sept. 30, 2012, the company’s strong financial position was further reflected by its debt-to-total-capital ratio of 23 percent.

Conference Call

At 10 a.m. EDT today, MPC will hold a webcast and conference call to discuss the earnings release and provide an update on company operations. Interested parties may listen to the conference call on MPC’s website at http://www.marathonpetroleum.com by clicking on the “2012 Third-Quarter Financial Results” link. Replays of the conference call will be available on the company’s website through Thursday, Nov. 15. Financial information, including the earnings release and other investor-related material, will also be available online prior to the webcast and conference call at http://ir.marathonpetroleum.com in the Quarterly Investor Packet.

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About Marathon Petroleum Corporation

MPC is the nation’s fifth-largest refiner, with a crude oil refining capacity of approximately 1.2 million barrels per calendar day in its six-refinery system. Marathon brand gasoline is sold through more than 5,000 independently owned retail outlets across 18 states. In addition, Speedway LLC, an MPC subsidiary, owns and operates the nation’s fourth-largest convenience store chain, with approximately 1,460 convenience stores in seven states. MPC also owns, leases or has ownership interests in approximately 8,300 miles of pipeline. MPC’s fully integrated system provides operational flexibility to move crude oil, feedstocks and petroleum-related

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products efficiently through the company’s distribution network in the Midwest, Southeast and Gulf Coast regions. For additional information about the company, please visit our website at http://www.marathonpetroleum.com.

Investor Relations Contacts:

Pamela Beall (419) 429-5640

Beth Hunter (419) 421-2559

Media Contacts:

Angelia Graves (419) 421-2703

Jamal Kheiry (419) 421-3312

In addition to net income determined in accordance with GAAP, MPC has provided supplemental “net income adjusted for special items,” a non-GAAP financial measure that facilitates comparisons to earnings forecasts prepared by stock analysts and other third parties. Such forecasts generally exclude the effects of items that are considered non-recurring, are difficult to predict or to measure in advance or that are not directly related to MPC’s ongoing operations. A reconciliation between GAAP net income and “net income adjusted for special items” is provided in a table on page 1 of this release. “Net income adjusted for special items” should not be considered a substitute for net income as reported in accordance with GAAP. We believe certain investors use “net income adjusted for special items” to evaluate MPC’s financial performance between periods. Management also uses “net income adjusted for special items” to compare MPC’s performance to certain competitors.

This release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements relate to, among other things, MPC’s current expectations, estimates and projections concerning MPC business and operations. You can identify forward-looking statements by words such as “anticipate,” “believe,” “estimate,” “expect,” “forecast,” “project,” “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 company’s control and are difficult to predict. Factors that could cause actual results to differ materially from those in the forward-looking statements include: our ability to successfully complete the acquisition of BP’s Texas City, Texas, refinery and related logistical assets, including, without limitation, the receipt of regulatory approvals and the satisfaction of other customary closing conditions; 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; completion of pipeline capacity to areas outside the U.S. Midwest; consumer demand for refined products; changes in governmental regulations; transportation logistics; the availability of materials and labor, delays in obtaining necessary third-party approvals, and other risks customary to construction projects; the reliability of processing units and other equipment; our ability to successfully implement growth opportunities; impacts from our repurchases of shares of MPC common stock under our stock repurchase authorization, including the timing and amounts of any common stock repurchases; other risk factors inherent to our industry; and the factors set forth under the heading “Risk Factors” in MPC’s Annual Report on Form 10-K for the year ended December 31, 2011 filed with the Securities and Exchange Commission (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 or in MPC’s Form 10-K could also have material adverse effects on forward-looking statements. Copies of MPC’s Form 10-K are available on the SEC website, at http://www.ir.marathonpetroleum.com or by contacting MPC’s Investor Relations Office.

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Consolidated Statements of Income (Unaudited)

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Supplemental Statistics (Unaudited)

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Supplemental Statistics (Unaudited) (continued)

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Segment Earnings Before Interest, Taxes, Depreciation & Amortization (Segment EBITDA)

(Unaudited)

Select Financial Data (Unaudited)

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