This week the API data carries extra weight, because the delayed EIA release gives traders longer to position on the industry figures. Middle East supply disruption is keeping crude highly sensitive to any sign of tightening or loosening in US balances, so early inventory signals have a bigger effect on prices than usual. Product stocks matter as well, since gasoline and distillate moves feed into views on refinery margins and winter fuel demand. The main risk sits with Thursday’s EIA report, which could quickly reverse any move made on the API numbers if the two diverge sharply.---The expected I had for the headline was a 1mn barrel draw. ---The API has the first word on US oil stocks, and this week, with the EIA delayed by the holiday, it keeps that role a day longer than usual.Summary:The API has released its weekly US oil inventory survey for the week ended November 6The API is an industry trade group that compiles voluntary data from oil companies, and it is released on Tuesday afternoons, US timeThe EIA, part of the US Department of Energy, uses mandatory surveys and is the market benchmarkThe EIA report adds production, trade, refinery runs, implied demand and Strategic Petroleum Reserve dataThe two reports can diverge, sometimes sharply, and the EIA figure usually takes over as the reference pointThis week’s EIA report is delayed to Thursday at 12:00 ET (17:00 GMT) because of the Veterans Day holidayThe American Petroleum Institute (API) has released its weekly survey of US oil inventories, giving traders a first look at stock changes for the week ended November 6. The official figures from the US Energy Information Administration (EIA) follow on Thursday, a day later than usual because of the Veterans Day holiday.The two reports cover the same week and many of the same categories, including commercial crude stocks, inventories at the Cushing, Oklahoma, storage hub, and gasoline and distillate stocks. They differ in three key ways: who compiles them, how complete the data is, and when they are published.The API is an industry trade association, and its weekly survey relies on figures that oil companies, refiners, pipeline operators and terminal owners submit voluntarily. The data goes first to subscribers on Tuesday afternoon, US time, and the headline numbers then circulate quickly through the market.The EIA is the independent statistical agency of the US Department of Energy. Its Weekly Petroleum Status Report is built from mandatory surveys of companies across the supply chain, which gives it wider coverage. It is normally published at 10:30 a.m. Eastern time on Wednesdays. This week, the EIA’s schedule moves the release to Thursday at 12:00 p.m. Eastern (17:00 GMT).The EIA report is also more detailed. As well as inventories, it includes domestic crude production, imports and exports, refinery runs and utilisation, implied demand for fuels, and holdings in the Strategic Petroleum Reserve. That breadth is why traders treat it as the benchmark and the API figures as an early indication.Because the two surveys use different methods and samples, their numbers can diverge, sometimes by several million barrels, and occasionally point in opposite directions. When the API and EIA agree, the API reading has usually set the tone in advance. When they differ, the EIA figure usually becomes the market’s reference point.With Middle East supply disruption keeping oil markets sensitive to any shift in US balances, the extra day’s wait leaves the API reading as traders’ main inventory signal for longer than usual. Thursday’s EIA report will show whether it holds. This article was written by Eamonn Sheridan at investinglive.com.