US oil refineries are running at full tilt as wars in the Middle East and Ukraine choke global fuel supplies, pushing utilization to 96 per cent nationwide and 100 per cent in the Midwest and Rocky Mountains, according to the US Energy Information Administration.

Exports of diesel and jet fuel have hit record levels after Iran closed the Strait of Hormuz, while Houthi threats and Russian drone strikes further tighten the market; US wholesale diesel futures have jumped 26 per cent this month, lifting refiner margins to a record high and boosting stocks of Valero and Marathon Petroleum.

The surge leaves little margin for error—any outage could spike prices worldwide. The Strategic Petroleum Reserve has fallen to 311mn barrels, near its operational minimum of 180mn to 200mn barrels, and commercial stocks at Cushing, Oklahoma sit at 20mn barrels. Analysts warn the buffer is exhausted, making the system vulnerable to further shocks.