The ULSD diesel market is experiencing an unprecedented refining margin environment as the closure of the Strait of Hormuz fractures global supply chains for middle distillates. Argus Media reports that since the start of "Operation Epic Fury," US Gulf Coast ULSD crack spreads versus WTI Houston have surged to a high of $66.64/bbl. (FACT: Argus Media, 2026) These crack spreads — the difference between the price of a barrel of crude and the finished diesel product — reflect extraordinary refinery profitability as the scramble for diesel supply intensifies globally.
However, the strength in crack spreads does not tell the full story. Argus notes that Gulf Coast ULSD differentials to NYMEX heating oil have come under pressure since the initial spike, partly because sky-high freight rates and war-risk insurance costs around the Strait of Hormuz are distorting arbitrage and trade flows. (FACT: Argus Media, 2026) The "knock-on" effect of the disruptions has been "a fundamental shift in US exports," as Gulf Coast refiners pivot to push as much diesel as possible to both Europe and Asia simultaneously to fill the supply gaps left by stranded Gulf production. (FACT: Argus Media, 2026)
On the other side of the world, China's major refiners — including Sinopec and private mega-refiner Rongsheng — have stopped signing new fuel export contracts for diesel and gasoline. Several Asian refiners heavily dependent on Middle Eastern crude have started to reduce crude throughput and cancel exports amid a lack of deliveries from the Persian Gulf, where some 14 million bpd of crude oil supply remains stranded. (FACT: DTN, March 5, 2026) Singapore's Jurong Island refineries are operating but face reduced throughput as regional crude slates shift to alternative grades that require different processing configurations.
Ukraine's drone campaign against Russian energy infrastructure has added a further layer of supply disruption. The Yaroslavl refinery — a key supplier of diesel to Russian domestic and export markets — was hit by Ukrainian drone strikes in April, reducing Russian distillate output at a time when the global market can least afford incremental losses. (FACT: Multiple news sources, April-May 2026) While Russia is not a primary supplier to European diesel markets following the 2022 sanctions regime, the loss of any refinery capacity in a supply-constrained world pushes Atlantic Basin refiners to run harder, tightening an already stressed system.
The IEA's May 2026 Oil Market Report confirms that global observed oil inventories drew by 129 million barrels in March and 117 million barrels in April. On-land stocks fell by 170 million barrels in April alone — equivalent to 5.7 million bpd of demand being met from storage. (FACT: IEA, May 13, 2026) The agency's base case — which assumes a gradual Hormuz reopening from Q3 2026 — still leaves the market in deficit until Q4, with only a "modest surplus" expected in the final quarter of the year. (FACT: Reuters, May 13, 2026)
The World Bank's April Commodity Markets Outlook forecasts energy prices surging 24% in 2026, with Brent averaging $86/bbl under a base case that assumes Hormuz disruption ends in May. (FACT: World Bank, April 2026) That assumption now looks optimistic. EU officials state that the price shock will persist through 2027. (FACT: Fortune, May 23, 2026) For ULSD diesel specifically, the structural deficit in middle distillate supply — driven by the simultaneous loss of Gulf refining, disrupted crude flows, and secondary impacts from Ukraine-Russia refinery attacks — means refining margins will remain elevated regardless of headline crude price movements. The 2022 rally in ULSD cracks was driven by Russia-Ukraine sanctions; the 2026 rally is driven by a physical supply hole that the IEA describes as "the largest supply disruption in history." (FACT: IEA, May 2026)
Action: Do not anchor expectations to Brent crude price movements — ULSD refining margins (crack spreads) are disconnecting from crude benchmarks. The $66.64/bbl USGC crack spread means $30-40/bbl of the finished diesel price is pure refinery margin driven by physical distillate scarcity. Purchase contracts should be negotiated on a fixed-dollar-per-gallon basis, not as a formula off NYMEX heating oil futures, because the relationship between crude, futures, and physical diesel has broken down. For Q3-Q4 2026, expect ULSD to command a premium of $1.00-$1.50/gal over gasoline at the wholesale level.
Horizon: The IEA deficit forecast extends through Q4 2026 even under the optimistic Hormuz reopening scenario. China's export halt removes 500,000-800,000 bpd of potential diesel supply from global markets. Russian refinery outages add further tightness. Assume elevated ULSD cracks through at least H1 2027, with potential for rationing in import-dependent markets through summer 2026.
Trigger: Watch (1) the USGC ULSD 62g Pipe differential to NYMEX heating oil — a widening differential signals physical tightness on the Gulf Coast regardless of futures; (2) China's diesel exports — if Sinopec and Rongsheng resume export contracts, it signals domestic demand destruction and provides global relief; (3) freight rates on the USGC-to-Europe diesel route — rates above $15/bbl signal structural arbitrage stress that keeps physical diesel prices elevated regardless of crude.