Commercial oil inventories across the Organisation for Economic Co-operation and Development (OECD) increased in August, but remained below historical benchmarks, with refined-product stocks still significantly lower than a year earlier, according to OPEC’s October 2026 Monthly Oil Market Report.
OECD commercial oil inventories rose by 36.6 million barrels from July to 2.808 billion barrels, preliminary data in the report show. Despite the monthly build, total stocks were 57.5 million barrels below their level in August 2025, 8.8 million barrels below the latest five-year average and 177.2 million barrels below the 2015–2019 average.
The figures point to a gap between the recent increase in stored oil and the broader level of inventory availability across developed economies, where commercial stockpiles remain below historical reference points used to assess market conditions.
Crude oil accounted for most of August’s increase, rising by 29.5 million barrels month on month to 1.351 billion barrels. Product inventories, which include refined fuels, increased by a further 7.1 million barrels to 1.458 billion barrels.
The two categories, however, showed contrasting year-on-year trends. OECD commercial crude stocks were 19.3 million barrels above their August 2025 level and 22 million barrels above the latest five-year average. Product stocks were 76.8 million barrels below a year earlier and 30.8 million barrels below the five-year average, highlighting the continuing weakness in the refined-products component of the inventory picture.
The combined inventory level was also well below the longer historical benchmark covering 2015–2019. Total OECD commercial stocks stood 177.2 million barrels beneath that average, while crude inventories were 96.8 million barrels below it and product inventories were 80.4 million barrels lower.
The difference matters for oil-market participants because crude stocks and refined-product inventories represent distinct stages of the supply chain. An increase in crude held by commercial operators does not necessarily translate into a comparable increase in available gasoline, diesel, jet fuel or other finished products.
Regional inventory movements
All three OECD regions recorded increases in crude inventories in August. OECD Americas crude stocks rose by 15.9 million barrels, Europe added 8 million barrels and Asia Pacific increased by 5.6 million barrels, according to the report.
Product stocks moved differently across the regions. OECD Europe recorded an increase of 13.1 million barrels, while the Americas drew down 3.6 million barrels and Asia Pacific reduced product inventories by 2.5 million barrels.
These movements left the overall OECD product-stock increase at 7.1 million barrels, despite declines in two of the three regions.
The report’s figures are preliminary and cover August 2026. They therefore provide a snapshot of commercial inventories during that month rather than a measure of current stock levels.
Stock cover remains below historical averages
OECD commercial inventories provided 60.4 days of forward demand cover in August, up one day from July, OPEC said.
That level remained 1.1 days below August 2025, 0.5 days below the latest five-year average and 2.7 days below the 2015–2019 average.
Forward cover measures how long existing inventories could meet projected demand, making it a useful indicator alongside the absolute volume of oil held in storage. The August reading shows that the monthly inventory increase had not restored stock cover to its recent five-year norm.
For oil-market participants, the data offer a more nuanced picture than the monthly build alone suggests. Crude inventories increased and exceeded their five-year average, but total commercial stocks remained below that benchmark because product inventories were still comparatively low.
OPEC’s figures do not, by themselves, establish that OECD economies face an imminent shortage of oil or refined fuels. They do, however, show that aggregate commercial inventories and forward cover remained below historical averages in August, even as stocks began to recover from July.
