US oil stocks surge as Iran war disrupts global energy flows — API reports gains in crude, gasoline, distillate inventories

US inventories of crude oil, gasoline and distillates all rose last week, according to data from the American Petroleum Institute, as the market weighs a prolonged US-Iran war and severe disruptions to Middle East oil shipping.

API said crude inventories increased by 7.1 million barrels in the week ended Sept. 11, while gasoline stocks rose 1.5 million barrels and distillates gained 1.6 million barrels. The figures are preliminary industry estimates ahead of the more closely watched Energy Information Administration report. The API says its weekly data are widely used by oil traders and companies.

The build in U.S. stocks comes as global oil markets face an unusual supply shock. Oil prices have climbed above $100 a barrel, with Brent reaching about $107.90 and WTI above $104.95 amid escalating Middle East disruptions, as as of 9.47am Tokyo on Wednesday (Sept. 16, 2026).

The key issue is the Strait of Hormuz. Reuters reported Sept. 15 that only four commodity vessels crossed the waterway on Monday, compared with a pre-war average of about 125 daily transits.

Hormuz normally handles roughly a fifth of global crude and LNG flows.

At the same time, Saudi Arabia's East-West oil pipeline has been disrupted, adding pressure to alternative export routes.

Higher US inventories do not necessarily mean the global oil market is adequately supplied.

The US can build stocks while international supplies remain constrained by shipping bottlenecks, damaged infrastructure and reduced exports from the Middle East.

The EIA's official Weekly Petroleum Status Report will provide the definitive government data and additional details on crude production, refinery utilisation, imports, exports and petroleum-product demand.