Marathon Petroleum Corporation

Marathon Petroleum Corporation is the largest independent petroleum refiner in the United States, operating 13 refineries with roughly 3.0 million barrels per day of crude processing capacity across the Gulf Coast, Mid-Continent, and West Coast regions, and controlling the general partner interest in MPLX LP, a large-scale midstream infrastructure company. The company generated $132.7 billion in revenue and $4.0 billion in net income attributable to shareholders in fiscal 2025.

This is a story about a business that earns its return on capital in the crack spread — the inherently cyclical margin between crude oil and refined products — and has chosen to return the overwhelming majority of its free cash flow to shareholders rather than diversify. In the five years since the Speedway retail sale, MPC has retired nearly half its shares, transforming the equity base at a pace that few industrial companies have matched. The discipline is genuine, and it has been rewarded: between mid-2021 and mid-2026, the stock appreciated roughly four-fold even as refining margins cycled from peak to trough and back.

The file turns on a single question: whether MPC's capital-return model can compound through the next down-cycle without the tailwind of an Iran-driven margin spike, or whether the buyback engine stalls just when shareholders need it most.