The refining margin we track — the 3-2-1 crack spread — is sitting near $60 a barrel, roughly double where it began the year (~$28). Numbers like that appear only in genuine crises: the last time was the 2022 diesel panic. It is natural to look at a figure that large, next to crude in the low-$70s, and conclude one of two things: refiners are gouging the market, or they must be paying far more for crude than the benchmark says.
Both instincts are pointing at something real. But the cleanest explanation is a third one: the headline crack overstates what refiners actually earn. It is a benchmark abstraction, not a profit-and-loss statement.
What the 3-2-1 crack actually measures
The 3-2-1 is a simple proxy: take 3 barrels of crude, assume they yield 2 barrels of petrol and 1 of distillate, value the products at hub spot prices, subtract the crude, and divide by three. Right now that maths runs hot because products are extraordinarily expensive relative to crude: reference gasoline near $3.05/gal (~$128/bbl) and ultra-low-sulphur diesel near $3.32/gal (~$139/bbl) against Brent around $72. That implies a petrol crack of roughly $56 and a diesel crack of roughly $67 — both near record highs at the same time, which is almost without precedent.
The formula is arithmetically correct. But it makes three assumptions that quietly flatter the refiner.
Why the paper number is not the cash number
1. The refiner is not running benchmark crude. The crack values the input at Brent — light, sweet, cheap. A complex refinery built to make diesel runs medium and heavy sour grades, and those are exactly the barrels a Middle East crisis makes scarce and dear. When Gulf supply is disrupted, sour differentials blow out: the refiner's actual feedstock can cost several dollars a barrel more than the Brent the crack assumes. This is the grain of truth in "they're paying more for crude than stated" — their real input cost sits above the benchmark.
2. The crack nets out no operating cost. Turning crude into clean products burns enormous energy — natural gas for process heat, hydrogen for hydrocracking and desulphurisation, power for the whole plant. Those costs have risen with the same tight energy market. The 3-2-1 ignores them entirely. Real cash margins are gross margins minus opex, and opex right now is not small.
3. The product basis is a hub, not a gate. The crack uses specific reference products at specific hubs. A given refinery's realised slate, quality and location differ; not every barrel it makes clears at the marker price.
Stack these up and the refiner's true cash margin is materially narrower than $60. The gap between the paper crack and the cash margin is the sour-crude premium plus the energy bill — the very things a supply crisis inflates.
So what is the crack telling us?
Not that refiners are banking $60 a barrel. It is telling us that product markets are under extreme physical stress — and it is mostly a diesel story. Russia is weighing a full diesel-export ban amid domestic shortages and drone damage to its refineries; Atlantic-basin distillate is tight; north-west European product inventories — ARA jet stocks recently hit a six-year low — have little slack. Britain is a net importer of diesel and leans heavily on those same north-west European and further-afield cargoes, so it is directly exposed to that tightness. When there is a shortage of product, whoever has product to sell earns a windfall. That is scarcity rent, not manipulation.
The two-speed market
This is why a low crude price and a record crack can coexist without contradiction. They are measuring opposite ends of the barrel:
- Crude is in glut. Stranded Gulf barrels are finally sailing after the ceasefire, OPEC+ is adding supply, and the war-risk premium is draining out of the flat price. Crude is cheap because there is too much of it.
- Products are scarce. The bottleneck moved downstream — into refining capacity, diesel export bans, and shipping logistics that a cheap barrel of crude does nothing to fix.
In a frictionless market, a $60 margin would pull crude up and products down until it closed. It has not closed because refiners cannot fully capture it — the constraint is downstream of the crude they buy.
Bottom line
Read the crack spread the way you would read a fever, not a bank balance. A record margin is a measure of how tight products are, not how much money refiners are pocketing — their cash margins are narrower once the real, dearer sour crude and the energy bill are paid. And the warning inside it is the one that matters for Britain: with crude cheap but diesel scarce, it is diesel, not crude, that sets the price at the pump. A falling oil price will not rescue the haulier, the farmer or the food-distribution chain if the diesel crack stays this wide — and the DESNZ pump series will feel the product market long before it feels the barrel.
The 3-2-1 crack on our prices page is a benchmark proxy (Brent crude vs Atlantic-basin reference products). It is published to show product tightness relative to crude, not to estimate refiner profit.