MPCMarathon Petroleum Corporation

Marathon Petroleum refines crude, and its earnings come not from the price of a barrel but from the gap between feedstock and fuel.

The key number is the refining margin: the gap between crude cost at the intake and revenue from petrol, diesel and jet fuel at the output. It can widen while crude falls and narrow while crude rises, so a refiner behaves differently from a producer — often in the opposite direction.

US capacity shrank for years: building a new refinery is expensive and politically difficult, while old ones closed. The resulting tightness is what holds margins above the historical norm — a structural rather than cyclical factor.

The company also owns a fuel retail network and a stake in a pipeline partnership that earns steady throughput income regardless of refining margins. Risks are planned and unplanned refinery outages and fuel specification requirements. Marathon pays a dividend and buys back stock very actively.