The US Strategic Petroleum Reserve (SPR) is the world's largest government emergency crude oil stockpile. In 2026 it was drawn down faster than ever in response to the Iran war: from about 415 million barrels before the conflict to 283.8 million barrels in late September 2026, the lowest level since 1982. This guide explains what the SPR holds, how releases work and how they affect WTI.
What the SPR Is
Created after the 1973–74 Arab oil embargo, the SPR stores crude oil in underground salt caverns at four sites on the US Gulf Coast: Bryan Mound and Big Hill in Texas, and West Hackberry and Bayou Choctaw in Louisiana. Its authorized capacity is 714 million barrels. The inventory peaked at about 727 million barrels in 2009–2010.
Does the SPR Hold WTI or Brent?
The SPR holds US crude in two categories, sweet and sour. Roughly 60% of the oil is sour (higher sulfur), which suits the many Gulf Coast refineries built to run heavier, sourer crude. The sweet portion is similar in quality to light sweet grades such as WTI, but it is stored on the coast, not delivered at Cushing, so it is not "WTI" in the futures-contract sense. The SPR holds no Brent, which is a North Sea benchmark.
Recent History
- 2022: after Russia invaded Ukraine, the Biden administration sold 180 million barrels over six months, at an average of about $96 a barrel, cutting the reserve to around 347 million barrels.
- 2023–2024: the Department of Energy repurchased oil when prices were at or below roughly $79 a barrel, and recovered additional barrels through earlier exchange returns, lifting the reserve to around 415 million barrels by early 2026.
- March 11, 2026: with the Strait of Hormuz closed, President Trump authorized the release of 172 million barrels over about 120 days as the US share of a record 400-million-barrel coordinated IEA release.
- Late September 2026: the SPR held 283.8 million barrels (week ending September 25), about 40% of capacity. A final 40 million barrels was authorized for delivery in November–December 2026.
Sales vs Exchanges
The DOE can sell SPR oil, or exchange it: companies borrow crude now and return it later with extra barrels as a premium. Much of the 2026 release was structured as exchanges, with reported premiums of roughly 24–26% and returns scheduled into 2028. Exchanges refill the reserve automatically, but only years later.
How SPR Releases Affect WTI
An SPR release adds physical supply on the Gulf Coast, which tends to weigh on US crude prices relative to international ones and can encourage exports. Its price impact depends on scale: the 2026 IEA release added very roughly 2.5–3 million b/d to the world market at its peak, against Hormuz losses many times larger, so it cushioned rather than reversed the price spike. Purchases to refill the reserve work the other way, adding demand. Because the SPR is on the coast, releases affect Gulf Coast grades and the WTI-Brent spread more directly than Cushing inventories.
Risks of a Low Reserve
With the reserve near 40% full, policymakers have less room to respond to the next disruption, and CNBC reported concerns that very low cavern levels can complicate operations. Refilling at 2026 prices would be expensive; the administration has floated using Venezuelan crude among other options.
Frequently Asked Questions
Does the US Strategic Petroleum Reserve contain WTI or Brent oil?
Neither, strictly speaking. The SPR stores US crude oil in salt caverns on the Gulf Coast in two broad categories: sweet (low-sulfur) and sour (higher-sulfur) crude. About 60% of the inventory is sour. The sweet crude is similar in quality to WTI-type light sweet grades, but it is not WTI delivered at Cushing, and the SPR holds no North Sea Brent.
Where is the Strategic Petroleum Reserve stored?
In underground salt caverns at four sites on the Gulf Coast: Bryan Mound and Big Hill in Texas, and West Hackberry and Bayou Choctaw in Louisiana. There are no SPR caverns at Cushing, Oklahoma.
How much oil is in the SPR now?
The SPR held 283.8 million barrels in the week ending September 25, 2026 — its lowest level since 1982 and about 40% of its 714-million-barrel authorized capacity — down from about 415 million barrels before the Iran war began in February 2026.
Does the quality of oil used to refill the SPR matter?
Yes. The Department of Energy buys crude that meets its sweet or sour specifications so that the barrels can be processed by Gulf Coast and Midwest refineries in an emergency. Refilling with the right mix of grades matters because many US refineries are configured for heavier, sourer crude than the light sweet oil the US mostly produces.
Sources
- DOE — Strategic Petroleum Reserve
- Wikipedia — Strategic Petroleum Reserve (United States)
- CNBC — Trump will release 172 million barrels of oil from the SPR (March 11, 2026)
- CNBC — Depleted strategic oil reserve nears level that raises concerns (Aug 15, 2026)
- 24/7 Wall St. — SPR at 44-year lows; another 40 million barrels (Sept 30, 2026)
- EIA — Weekly U.S. ending stocks of crude oil in the SPR
Disclaimer: This article is for general information only and is not investment advice. Trading oil, futures and energy securities involves substantial risk of loss.