U.S. base oil exports remained healthy in June despite tighter domestic supply, with shipments exceeding 3 million barrels, according to the latest figures published by the U.S. Census Bureau.
The volume was down from more than 3.25 million barrels in May and 14% lower year on year, however. The decline continues a general trend of declining exports and month-to-month volatility. U.S. shipments fell as low as 2.819 million in September and 2.355 million in November 2025.
Base oil producers continue to send millions of barrels to international markets each month, while the amount of feedstock available to support those shipments has become more constrained. A tightening feedstock pool can restrict production even while demand for U.S. base oils remains strong enough to support substantial exports.
Base oils and diesel can vie for feedstocks at plants capable ofmaking both products. When diesel becomes much more valuable relative to crude — known as the crack spread — the incentive to maximize fuel production increases. The U.S. diesel crack spread reached a record $102.20 per barrel on Aug. 17, according to Reuters.
The Energy Information Administration raised its forecasts for U.S. gasoline and diesel prices as higher crude prices and tighter fuel supplies pushed product prices higher. The agency’s June outlook put the average 2026 wholesale diesel price at $3.40 per gallon, $1.34 higher than its February forecast.
Further complicating maerket trends in hurricane season, a period which typically sees base oil producers be more conservative in terms of exports, Gabriela Wheeler, Lubes’n’Greases’ base oils editor, told Lube Report.
“Producers like to have extra inventories to cover potential supply disruptions due to severe weather. This year, it has been particularly difficult to keep extra supplies because the market has been extremely tight since the start of the war in Iran.”
Disruptions to crude and refined-product flows have tightened global fuel markets, contributing to these stronger U.S. refining margins. Major U.S. refiners reported sharply higher second-quarter profits as refining margins increased.
HF Sinclair’s Tulsa refinery is integrated with its base-oil operation, while Motiva’s Port Arthur manufacturing complex includes the largest base-oil plant in the Western Hemisphere. HF Sinclair’s adjusted refinery gross margin rose 57.3% year on year to $25.95/bbl in the second quarter, while its refining segment’s adjusted core profit more than doubled to $1.02 billion.