Global oil inventories are grouped into three major components. The first covers OECD commercial oil inventories and Strategic Petroleum Reserves (SPRs), with data sourced from OECD national government reports. The second covers commercial oil inventories and SPRs in non-OECD countries, which have grown in significance since non-OECD oil demand surpassed that of the OECD in 2015. Tracking non-OECD oil inventory levels, however, remains challenging due to the lack of available good-quality data. Estimates for these stocks are primarily based on monthly data from major producer and consumer countries, as published
by the Joint Organisations Data Initiative (JODI), alongside official sources from major non-OECD countries. The third component of global oil inventories is ‘oil at sea’, including ‘oil afloat’ and ‘oil in transit,’ which serves as an important operational link between exporting and importing countries.

Since the beginning of 2025, global oil inventories increased by 304 million barrels (mb) to reach 8,482 mb at the end of September 2025, according to the latest available data. The OECD commercial oil stocks increased by 90 mb, while OECD SPR dropped marginally by 4 mb. The non-OECD oil stocks and oil at sea increased by 62 mb and 156 mb, respectively. The build in OECD commercial stocks from 1Q25 to 3Q25 could be attributed to higher imports into the region. For OECD SPRs, the decline was due to stock draws in OECD Europe and OECD Asia Pacific. However, SPRs in OECD Americas saw a build. This was driven mainly by steady additions to the US SPR, which have risen by about 3 mb per month, as the Administration replenishes the significant releases made back in 2022. Between January and September 2025, the observed build in total OECD commercial oil inventories was driven by an increase in OECD crude and product stocks of 38 mb and 52 mb, respectively.

The build in OECD crude oil stocks was a result of steady and robust supply, combined with higher imports within OECD countries. More recently, the build-up in oil at sea is attributed to higher output from few key producing countries, that increased their crude exports. In the OECD regions, combined crude and refined product stocks held in OECD Americas increased by 58 mb. This build was driven by a 12 mb increase in crude stocks, combined with a rise of 46 mb in products stocks over the same period. The crude build occurred on the back of year-on-year lower refinery utilization. In OECD Asia-Pacific, both crude and product inventories have risen this year, resulting in a combined oil stock build of 26 mb. Higher crude imports supported crude stocks, while lower demand caused product stocks to increase. In OECD Europe, most of the build since the beginning of this year has come from a 7 mb increase in crude stocks, while product stocks have experienced a slight drop of 1 mb.

Despite all of this, OECD commercial oil stocks in September remain 122 mb below the 2015-2019 average. In addition to the OECD commercial oil stocks build, the global oil stock increase was driven by the rise in non-OECD oil stocks and oil at sea. The build in non-OECD oil stocks was spurred by the ongoing build in China’s SPR. In the first three quarters of 2025, crude oil inventories in China increased by 37 mb, or 135 tb/d. In terms of days of forward cover, total oil inventories in non-OECD countries stood at 50 days at the end of September, which is still well below the OECD country level of 88 days. As oil demand in non-OECD countries rises further in the coming years, supported by economic expansion, there will be a need to further expand storage facilities to create an adequate level in terms of days of forward cover.
Source: OPEC