Marathon Oil Corporation

Lee Tillman served as Chairman, President, and CEO from August 2013 until the ConocoPhillips acquisition closed in November 2024. Investment decisions — primarily capital allocation across Marathon's US unconventional basins and its Equatorial Guinea operations — were managed through a centralized corporate planning function reporting to Tillman. The board of directors held final authority over the annual capital budget, which in its final independent years ran in the $1.7–$2.0 billion range (per the firm's earnings releases).

Marathon Petroleum Corporation was the downstream refining and marketing business of the original integrated Marathon Oil Company. The two entities separated in a 2011 corporate spin-off that created Marathon Oil as an independent E&P company focused on upstream exploration and production. Marathon Petroleum took the refineries, retail network, and Speedway brand. The two companies have not been operationally linked since, though they do share a lineage tracing back to Standard Oil.

Marathon Oil historically funded the Marathon Oil Company Foundation as its primary philanthropic vehicle, with grant-making focused on communities where the company operated — Houston, Eagle Ford counties in South Texas, and Bakken-region counties in North Dakota. The foundation's governance was separate from the commercial board, though executive officers frequently served as foundation trustees. Post-acquisition, ConocoPhillips has not publicly detailed the foundation's future structure.

Marathon consistently prioritized operator-controlled acreage over non-operated minority stakes, which let the company dictate drilling pace and completion design without relying on external partners' capital budgets. That operational control came at the cost of higher capital intensity. By 2024, Marathon had also fully exited international theaters beyond its long-held Equatorial Guinea position — a cleaner geographic footprint than peers like Hess or APA Corporation maintained.

Marathon operated across four US unconventional basins: the Bakken in North Dakota, the Eagle Ford in South Texas, the STACK/SCOOP formations in Oklahoma, and the Permian Basin in New Mexico. The company also maintained an offshore and onshore upstream presence in Equatorial Guinea, Africa, where the Alba gas and condensate field constituted its principal international asset. The US portfolio represented the vast majority of production and capital spending.