As of December 2025, China, the United States, and Japan collectively held the largest strategic oil inventories globally, according to estimates from the U.S. Energy Information Administration (EIA). These figures predate the coordinated emergency release of strategic petroleum reserves by International Energy Agency (IEA) member countries in March 2026, which was prompted by the effective closure of the Strait of Hormuz. The EIA's analysis, detailed in its Short-Term Energy Outlook (STEO) for March 2026, provides insights into the strategic stockpiling efforts of major oil-consuming nations.
The establishment of strategic oil stocks dates back to the 1970s, when the United States and other Organization for Economic Co-operation and Development (OECD) countries sought to create a buffer against potential supply disruptions. The recent coordinated release underscores the continued relevance of these reserves in managing global energy security, particularly in the face of geopolitical tensions impacting critical shipping lanes.
Estimating strategic oil inventories presents challenges due to varying levels of transparency across nations. The EIA adopted a conservative approach, defining strategic inventories primarily as government-owned stocks or those held by national oil companies (NOCs). For some countries, the definition was further limited to on-land storage facilities. Inventories held in commercial, floating, or underground storage were generally excluded, with notable exceptions made for China, where commercial inventories are considered part of its strategic reserves.
China emerged as the leading holder of strategic oil inventories by December 2025. The EIA estimates that China significantly expanded its strategic reserves throughout 2025, adding an average of 1.1 million barrels per day. This aggressive accumulation brought China's total strategic oil inventories to nearly 1.4 billion barrels by the end of the year. Preliminary data suggested that China continued to build these reserves into 2026, even before the March emergency release. The EIA's estimates for China's inventories are based on a comprehensive analysis of import, export, refining, and inventory data from various official and third-party sources, as China does not publicly report its oil inventory figures. The EIA's definition for China's strategic inventories includes both government-held and commercial stockpiles, reflecting directives to Chinese NOCs since 2024 to augment commercial stockpiles for emergency purposes. Within this total, government-held inventories in China were estimated at approximately 360 million barrels in December 2025, comparable to the U.S. Strategic Petroleum Reserve (SPR) level. China's commercial crude oil inventories, including those at refineries, were estimated to have reached a substantial 1 billion barrels by December 2025, significantly exceeding the 411 million barrels held commercially in the United States during the same period.
The United States held the second-largest strategic oil reserves. The U.S. SPR, established in 1975, has a total storage capacity of 714 million barrels. As of December 2025, the SPR contained 413 million barrels. Ahead of the coordinated release in March 2026, SPR stocks had briefly increased to over 415 million barrels, and by April 10, 2026, they stood at approximately 409 million barrels. These SPR figures are distinct from the more than 400 million barrels of commercial crude oil inventories maintained within the United States.
Japan ranked third in strategic oil inventory holdings, with government-held reserves reaching 263 million barrels as of December 2025. This figure excludes international joint stockpiling inventories and commercial inventories held by companies under strategic mandates as required by Japanese law. Japan's Oil Stockpiling Act mandates that industry participants maintain approximately 220 million barrels (equivalent to 70 days of demand) in commercial inventories, in addition to the government's 90-day strategic reserve. This dual approach ensures a robust supply cushion.
Within the broader OECD, Europe held an estimated 179 million barrels in government strategic inventories as of December 2025, according to the IEA. South Korea also maintains significant strategic oil stockpiles, with an average of 79 million barrels recorded during 2025. These holdings contribute to the collective energy security of the developed economies.
Estimating strategic inventories for non-OECD countries, excluding India, proved more challenging. For Saudi Arabia, the United Arab Emirates (UAE), and Iran, the EIA's estimates for strategic inventories were derived from reported December 2025 average refinery and commercial inventories, as distinguishing between commercial and strategic storage is difficult. Saudi Arabia was estimated to hold an average of 82 million barrels in on-land storage as of December 2025. This estimate does not encompass inventories reportedly held in leased crude oil storage sites in South Korea and Japan. The UAE held an average of 34 million barrels in on-land oil inventories as of December 2025. The UAE also possesses substantial underground storage capacity in Fujairah, the specifics of which are not publicly known, and is actively working to expand this capacity. Additionally, the UAE reportedly leases storage facilities in South Korea, Japan, and India.
Iran held an average of 71 million barrels of on-land oil inventories as of December 2025. Reports indicate that Iran may also hold crude oil in bonded storage within China, though current inventory levels in such facilities are not estimated by the EIA. India's strategic petroleum reserves, managed by the Indian Strategic Petroleum Reserve Ltd. (ISPRL), held 21.4 million barrels of crude oil as of March 2025. India also had an additional 3 million barrels stored at its Mangalore site on behalf of the Abu Dhabi National Oil Company (ADNOC), which is not considered part of India's strategic reserve. An agreement between ADNOC and ISPRL permits ADNOC to use this site for commercial storage, provided that at least 50% of its capacity remains available for ISPRL's strategic use. India has also explored options for storing oil internationally, including discussions with Oman regarding leasing space for approximately 5 million barrels.
The EIA's analysis highlights the concentration of strategic oil reserves among a few key nations, underscoring their critical role in global energy market stability. The methodologies employed, particularly the inclusion of commercial stocks in China's strategic reserves, reflect the unique approaches taken by different countries to ensure energy security. The data provides a snapshot prior to a significant event that tested these reserves, offering a baseline for future assessments of global oil inventory levels and their impact on market dynamics.
