Key Takeaways

• Refineries can’t make more diesel without also making gasoline and jet fuel in roughly fixed proportions, so a diesel export ban, and associated rapid diesel inventory build, could potentially force refiners to shut down more than half of Gulf Coast capacity.
• That much lost refining capacity means gasoline supply would also shrink by about 2,100 thousand barrels a day — so a policy meant to lower diesel prices could raise gasoline prices instead.
• If the government restricts fuel exports once, investors and refiners will expect it could happen again, making them less willing to invest in new capacity — which means less future supply and, ultimately, higher prices over time.

Every week since June, diesel has cost a little more at the truck stops along I-10 and the co-ops lining the Corn Belt — and the political ramifications have now reached the halls of Congress and the White House. The proposed solution: restrictions on petroleum product exports. The argument is straightforward — American refineries export diesel, so keep that diesel home and prices fall.

Diesel Cracks Spike as Inventories Hit 26-Year Low

Source: Bloomberg.

As shown in the chart above, diesel crack spreads are exceeding $100 per barrel while distillate inventories sit at a 26-year seasonal low. The cause is well documented: nearly 5 million barrels per day of global refinery capacity has been curtailed by the Iranian conflict and Ukrainian strikes on Russian refineries, leaving markets acutely undersupplied.

Should the administration proceed with a full export ban, we estimate it would take approximately 50 days to fill domestic storage with the excess distillate production that would now be trapped at home — a timeline that runs conveniently close to an election now 42 days away, as of 9/24/26. The political logic is clear. The economic consequences are another matter: European diesel supply would enter crisis, U.S. refiners would be forced to cut runs as storage fills, and the resulting reduction in total refined product output would ultimately tighten supplies of gasoline and other products as well. A short-term fix with significant long-term costs.

In The Extreme: Half the Gulf Coast Refiners Could Be Idled

A U.S. refinery does not exclusively make diesel. It transforms crude oil into a slate of products — gasoline, diesel, jet fuel, petroleum coke, and a dozen others — in proportions that the laws of chemistry and billions of dollars of fixed infrastructure have largely locked in place. The EIA's June 2026 yield data puts the U.S. slate at 43.8% gasoline and 29.6% distillate. Refiners can tune secondary units — hydrocrackers, FCCs, and cut points — to shift yields modestly at the margin, but the range is narrow.

The math behind a diesel export ban is straightforward. The U.S. exports 1,440 thousand barrels per day of distillate on a trailing 52-week average. With domestic distillate stocks standing at approximately 107.9 million barrels as of September 11, redirecting those exports to domestic markets fills available storage capacity in roughly 50 days at consistent utilization and yield assumptions.

The immediate market effect would be a sharp collapse in the diesel crack spread as surplus barrels flooded domestic storage. A targeted diesel-only ban — leaving gasoline and jet fuel exports intact — would initially allow refiners to maintain full throughput, with the profitability of other products offsetting a weakening distillate crack. Year-to-date gasoline cracks have averaged $42 per barrel and jet fuel $84 per barrel; under those assumptions, the diesel crack would need to reach approximately negative $100 per barrel before a Gulf Coast refinery would be compelled to reduce runs.

In practice, it would never get that far. Distillate prices would go negative well before physical storage filled, as markets priced in the inevitable. Refiners would begin cutting throughput within weeks in anticipation — reducing output not just of diesel, but of every product in the barrel. The policy designed to lower diesel prices at the pump would ultimately tighten supplies of gasoline, jet fuel, and other refined products as well.

No policy can repeal the underlying math. Distillate represents 29.6% of refinery output, so eliminating 1,440 thousand barrels per day of distillate exports requires total crude throughput to fall by approximately 4,900 thousand barrels per day — simply 1,440 divided by 0.296. Gulf Coast refining capacity, the source of nearly all U.S. product exports, runs roughly 9,500 thousand barrels per day. Sustaining zero distillate exports is therefore the steady-state equivalent of idling 51% of Gulf Coast refining capacity.

The collateral damage is unavoidable. When half the Gulf Coast refining complex goes dark to solve a diesel problem, gasoline output falls by approximately 2,100 thousand barrels per day alongside it. Diesel — the product the ban was designed to protect — ends up short. So does every other product in the barrel. The U.S. consumer, promised relief at the diesel pump, pays more at the gasoline pump instead.

The Refining Trade

Ultimately, free market economics must prevail. Higher crack spreads are precisely the signal that incentivizes refiners to maximize throughput, attracts capital toward capacity expansions, and — over time — brings prices down. An export ban perversely does the opposite: it distorts the price signal, destroys the economics that would otherwise encourage higher production, and leaves the consumer worse off than before the policy was enacted.

Any policy that compels refineries to operate at high utilization irrespective of profitability is more destructive still. Beyond the immediate economic damage, these interventions carry a longer-lasting risk: once markets learn that future administrations may manipulate fuel economics for short-term political gain, the cost of capital for U.S. refining rises permanently. Investors demand a higher return to compensate for regulatory risk they cannot predict or hedge. Higher capital costs mean less investment. Less investment means less capacity. Less capacity means less diesel — the very outcome the policy sought to prevent.

The irony is complete. A policy conceived to lower diesel prices, if pursued consistently or replicated by future administrations, would structurally reduce the refining investment that is the only durable path to lower prices. We are left with a simple question: is 42 days of potentially lower prices worth the long-term damage to the industry asked to provide them?

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