Notice of Exempt Solicitation. Definitive Material. (px14a6g)

March 27, 2017

Dear Marathon Petroleum Corporation Shareowner:

Support Shareowner Proposal #6 on Climate Change Reporting

CalPERS is the largest state public pension fund in the United States with $311 billion ¹ in total assets under management and long-term owner of approximately 2,012,000 shares in Marathon Petroleum Corporation. CalPERS will be voting FOR shareowner proposal #6 at the company’s April 26, 2017 annual meeting of shareowners.

Systemically Important Carbon Emitters (SICEs)

After completing a review of the CalPERS global equity portfolio, we identified 100 companies as significant carbon emitters responsible for over 50% of the portfolio’s total carbon emissions ² . CalPERS defines these companies as systemically important carbon emitters (SICEs) – with Marathon Petroleum Corporation being one of them. Further, we believe proposal #6 is of particular significance in light of the global consensus regarding climate change and emission reduction targets reflected in the Paris Agreement. The importance of the proposal’s request is also underscored by the efforts of Financial Stability Board (FSB), an international body mandated by G-20 leaders to develop efficient climate-related financial risk disclosures.

Request for an Assessment of the Company’s Portfolio under a 2 Degree Scenario

Consistent with the CalPERS Investment Beliefs, we believe effective management of environmental factors, including those related to climate change risk increase the likelihood that companies will perform well over the long-term. We support the request of proposal #6 asking Marathon Petroleum Corp. issue a report on the company’s strategy for aligning its business plan with the well below 2 degree Celsius goal of the Paris Agreement, while continuing to provide safe, affordable and reliable energy. The report should include:

The impact of a below 2 degree scenario on Marathon Petroleum’s current business model, business lines and products; and

Plans to integrate technological, regulatory and business model innovations such as advanced biofuels, fuel cells, and electric vehicle charging infrastructure.

¹ CalPERS total assets under management at fiscal year ending February 28, 2017.

² Based upon CalPERS ownership portion of total scope 1 + scope 2 emissions.

PLEASE NOTE: The cost of this solicitation is being borne entirely by CalPERS and is being done through the use of the mail and telephone communication. CalPERS is not asking for your proxy card. Please do not send us your proxy card. For additional information, please contact Garland Associates, Inc. at (561) 366-1165.

Vote FOR Shareowner Proposal #6 Requesting a Climate Change Policy and Reporting

CalPERS believes investors will benefit if the company provides accurate and timely disclosure surrounding environmental risks and opportunities associated with climate change. As a significant Marathon Petroleum Corporation investor we encourage shareowners to support proposal #6.

For questions about the CalPERS vote please contact Todd Mattley, CalPERS Investment Officer at INVO_GE_Corporate_Governance_Engagements@calpers.ca.gov or 916-795-0565.

Thank you for your support.

Sincerely,