The scarcity rent
What the domestic-shortage framing obscures is the refining margin, and the margin is the whole story. The diesel crack spread — the refiner’s gross margin over crude — has done something in 2026 it had never done before, and it keeps setting new records. It first topped $102 a barrel on August 17, the first triple-digit print in history; then, as the U.S.-Iran war reignited over the weekend of August 30 — a US strike on Larak Island inside the Strait of Hormuz, an Iranian missile-and-drone response against US bases, and a fresh Trump threat against Iran’s main crude-export terminal at Kharg Island — it pushed to a new all-time high above $106 on September 1. Normal is $20 to $40. Crucially, this is not a crude-price story. Even as the renewed strikes lifted Brent back above $91 and WTI into the mid-$80s, diesel’s premium over crude widened rather than compressed: since the pre-war baseline of late February, ultra-low-sulfur diesel is up roughly 71 percent while Brent is up only about 26 percent. It is a refining story: with several million barrels a day of global refining capacity knocked offline — Ukrainian strikes on Russian refineries, Middle East damage, a Russian diesel-export ban, lost Hormuz product flows — the world cannot turn enough crude into middle distillates, and the marginal barrel of diesel is being auctioned. Retail diesel now sits near its wartime high, around $5.63 a gallon, and domestic distillate inventories are at the lowest seasonal level on record. Independent trade analysts have reached the identical diagnosis the correspondents did: the world is not short of crude in the traditional sense; it is short of the capacity to refine crude into diesel and jet.
The refiners’ results show who is collecting on that. Second-quarter net income roughly quadrupled across the sector — Marathon from about $1.2 billion to $5.1 billion, Valero from about $714 million to $3.7 billion, Phillips 66 from about $900 million to $3.8 billion, Exxon’s products segment from about $1.37 billion to $5.47 billion — with per-barrel refining margins doubling or better and Exxon posting record second-quarter diesel output. The mechanism is elegant and entirely legal: buy discounted heavy-sour Canadian and Venezuelan crude, run it through sophisticated coking and hydrocracking, and sell the finished distillate into a world market where scarcity margins are enormous. The renewed Hormuz threat only sharpens the position: when Middle East medium and heavy sour is curtailed, complex Gulf Coast refiners optimized for sour feed bid up the alternatives, firming US and Canadian heavy-sour differentials — Mars traded at a premium to WTI at the spring peak, its strongest since 2020, and Western Canadian Select’s discount narrowed to multi-month highs — so the barrels at the heart of this trade become more valuable, not less, each time the strait is threatened. That is not the profile of a refining shortage. It is the profile of an extremely valuable refining position. A rough gross product-over-crude value on just the increase in diesel and jet exports lands near $85 million a day — on the order of $31 billion annualized — which, whatever one deducts for the real costs of running a refinery, is a fair measure of the incentive in play.
The reframe: swing supplier, not shortage victim
Put the pieces together and the picture inverts. The world genuinely is short of diesel and jet. The United States is not fundamentally short of either crude or refining capability. Its highly utilized refining system has instead become the principal balancing supplier to a starved global product market — running hard, exporting into foreign bids, and consequently draining its own inventories, while American consumers pay prices set by the global scarcity. The consumer bears much of the cost of the shortage; the refining sector captures much of the scarcity rent. Saying “America has a diesel shortage” collapses that distinction. America does not have a diesel-production problem. America is participating in a global diesel shortage — as its arbitrageur of last resort.
