Annual Report and Proxy

Dear Marathon Oil Corporation Stockholder,

2021 was an outstanding year at Marathon Oil, as evidenced by our bottom line financial results and environmental, safety and governance (ESG) excellence that compete not only with the best companies in energy, but with the best in the S&P 500.

We’re particularly proud of our strong safety performance, disciplined capital framework and compelling return of capital to stockholders, including executing over $1 billion of share repurchases since October and four consecutive base dividend raises, representing a cumulative 133% increase.

Throughout the year, we did not waver from our reinvestment rate capital allocation framework, generating over $2.2 billion of free cash flow, including approximately $900 million during fourth quarter alone, and returning that cash back to you, our stockholders. During fourth quarter, we returned more than 70% of our cash flow from operations to equity investors, significantly exceeding our minimum 40% commitment.

Marathon Oil believes continuously improving all elements of our ESG performance is foundational to maximizing longterm stockholder value. During 2021, we made remarkable progress toward our ESG objectives, including achieving our 30% greenhouse gas (GHG) intensity reduction target and improving total Company gas capture to 98.8%. In early 2022, we announced new environmental objectives that complement our existing 2025 GHG intensity goal, and which are consistent with the trajectory of the Paris Climate Agreement. Ultimately, we believe these new quantitative objectives highlight our commitment to meeting global energy demand with leading environmental performance.

Your Board of Directors and management cordially invite you to attend our 2022 Annual Meeting of Stockholders, to be held May 25, 2022, in the Level 6 Auditorium of One MRO, 990 Town & Country Blvd., Houston, TX 77024, at 10:00 a.m. Central Time. In the event it is not possible or advisable to hold our Annual Meeting in person because of the COVID-19 pandemic, we will announce alternative arrangements for the meeting as promptly as practicable, which may include holding the meeting virtually. If we take this step, we will announce the decision to do so in advance.

We value the communication we have established with our stockholders. We look forward to continuing to hear your views, and we ask for your continued support as we work to maximize the value of your investment in our Company.

We are making our proxy materials accessible online, which allows us to provide our stockholders with the information they need, while lowering the costs of delivery and reducing the environmental impact of our Annual Meeting. Please read the Proxy Statement for more information about how to access the proxy materials online.

On April 13, 2022, we plan to mail to our U.S. stockholders a notice explaining how to access our 2022 Proxy Statement and 2021 Annual Report, request a printed copy of these materials and vote online. All other stockholders will continue to receive copies of the Proxy Statement and Annual Report by mail.

Your vote is important. Whether or not you plan to attend the meeting, we encourage you to vote promptly so that your shares will be represented and properly voted at the meeting.

Sincerely,

Signature of Lee M. Tillman
Lee M. Tillman
Chairman, President and Chief Executive Officer
Signature of Marcela E. Donadio
Marcela E. Donadio
Independent Lead Director

Dear Shareholders,

2021 was a year of comprehensive delivery against our framework for success, as evidenced by bottom line financial results and environmental, social and governance (ESG) excellence that compete not only with the best companies in energy, but with the best in the S&P 500.

We stayed disciplined and did not waver from our reinvestment rate driven capital allocation priorities, generating over $2.2 billion of free cash flow, including about $900 million during fourth quarter alone. We dramatically enhanced our balance sheet quality by accelerating $1.4 billion of gross debt reduction.

We then successfully transitioned to market leading return of capital to our equity investors, prioritizing our shareholders as the first call on cash flow generation via our differentiated percentage of cash flow framework. During fourth quarter, we returned more than 70% of our cash flow from operations to equity investors through the powerful combination of a sustainable and competitive base dividend and consistent share repurchases, significantly exceeding our minimum 40% commitment.

While others in our space may once again be focused on growing their production, we are focused on growing the per share financial metrics that matter most to our equity valuation – our cash flow per share and our free cash flow per share. Since October 2021, we have executed over $1 billion of share repurchases – achieving an 8% reduction to our outstanding share count in just 41/2 months. Beyond driving significant underlying per share growth, share repurchases are highly synergistic with base dividend growth over time and we recently raised our quarterly base dividend for the fourth consecutive quarter.

In 2021, we also achieved significant progress against core safety and environmental objectives including the second best annual Total Recordable Incident Rate1 (TRIR) since becoming an independent E&P. We also achieved our target to reduce greenhouse gas (GHG) intensity by at least 30% relative to 2019 baseline and improved total company gas capture2 to 98.8%.

Early in 2022, we announced new quantitative environmental objectives that highlight our commitment to meeting global energy demand with leading environmental performance. This includes near, medium and long-term goals focused on GHG intensity, methane intensity and gas capture, and a commitment to the 2030 World Bank Zero Routine Flaring initiative.

As we look ahead to 2022 and beyond, you can expect more of the same from our company: peer leading capital efficiency and operational execution, significant free cash flow generation and market leading return of capital to shareholders, all underpinned by our commitment to continue to drive ESG excellence.

Finally, we would like to thank all of our dedicated employees and contractors who made 2021 another exceptional year for our company.

Signature of Lee M. Tillman
Lee M. Tillman
Chairman, President and CEO
Signature of Marcela E. Donadio
Marcela E. Donadio
Independent Lead Director