Private survey shows US crude stocks fell by 2.1m barrels last week

The headline numbers from Reuters, citing a private survey:

• Crude inventories dropped by 2.09 million barrels during the week ending October 2, according to sources who spoke on condition of anonymity. Gasoline supplies decreased by 1.37 million barrels, while distillate stockpiles grew by roughly 461,000 barrels compared with the prior week, the sources added.

API vs EIA: how the two weekly US oil inventory reports differ

Each week, oil traders receive two assessments of US crude and fuel inventories. Both reports address the same topic, but they originate from separate organisations, rely on distinct methodologies, and hold differing significance in the marketplace.

The initial report is produced by the American Petroleum Institute (API), the leading US oil and gas industry association. It typically comes out on Tuesdays at 4:30 pm US Eastern time. Participation by member companies is voluntary, meaning the survey captures a substantial portion of US capacity but not the entirety. The full document is available via subscription, though the key crude, gasoline, distillate, and Cushing numbers are broadly disseminated by news outlets shortly after their release.

The subsequent report is issued by the Energy Information Administration (EIA), the statistical division of the US Department of Energy. Its Weekly Petroleum Status Report generally arrives on Wednesdays at 10:30 am Eastern. Operators such as refineries, terminals, and pipelines are required to report, and the data is freely available to the public. The EIA report also has a wider scope. In addition to inventory figures, it provides estimates for domestic crude output, imports and exports, refinery utilization, implied product demand, and Strategic Petroleum Reserve holdings.

Owing to variations in sampling and methodology, the two reports frequently differ, sometimes by millions of barrels and occasionally in the direction of the change. A significant API build may precede an EIA draw, or the opposite may occur.

This explains why markets treat each report differently. The API numbers serve as an early signal that can influence prices during thin after-hours trading and shape market expectations. The EIA figures are the official reference point: they are legally required, more thorough, and government-sourced, and typically trigger a stronger market reaction when published against analyst predictions.

The practical approach is to view the API as a preliminary indicator and the EIA as the more reliable measure. Neither is definitive. The EIA's weekly estimates are subsequently reconciled with its more comprehensive monthly data. US holidays can delay either report by a day.