Why has U.S. refinery utilization fallen to 92.5, down 5.6% in a month?

U.S. refinery utilization is 92.5, down 5.6% over the past 30 days, off a high of 98 and a low of 88.6. Less of the country's refining capacity is running than a month ago. A working fuel buyer wants to know why, and whether it is the reason diesel keeps climbing.

Diesel is 6.382, up 14.0% over the same 30 days. Gasoline is 4.603, up 9.4%. The obvious read is that refineries slowed, product got scarcer, and prices rose to match. Less output, higher pump. It fits on the first pass.

Then RBOB gasoline breaks it. Wholesale gasoline is 3.036, down 5.5% over the month. Retail gasoline rose almost ten percent while the wholesale barrel it comes from fell. A supply squeeze on gasoline would push both up together. One up and one down says the gap between what gasoline costs the station and what the station charges widened, and the widening belongs to retail pricing rather than a shortage at the refinery.

Diesel tells a cleaner version of the same thing. The diesel retail-wholesale spread is 1.627 now, wider by 0.523 over 30 days. The space between the rack price and the pump price grew by about half a dollar a gallon in a month. Part of diesel's 14.0% is the wholesale barrel getting dearer, and part is that widening retail margin. Both moved the same way for diesel, which is why diesel is the tighter of the two fuels right now.

If refineries cut runs because the economics turned against them, the crack spread would show it first. The 3:2:1 crack is 59.08, down only 3.01 over the month. A refiner turning three barrels of crude into two of gasoline and one of diesel still clears about 59 on the math, barely below where it was. Refiners did not slow down because making fuel stopped paying. At 59 they have every reason to run hard.

So the drop in utilization is not a margin story. Something took those barrels of capacity offline while the incentive to run stayed strong. October is fall turnaround season, when refiners schedule maintenance they put off over the summer driving months, and planned downtime pulls utilization down without touching the crack. The wire points the same direction. Goldman says diesel could stay high through 2027 because refineries are struggling to meet demand, which is a problem of capacity and maintenance rather than price. The President blamed gas prices on refinery issues rather than on the Strait of Hormuz. Different speakers, same finger pointed at the plants themselves.

Crude supply is the other candidate, and it is recovering rather than failing. Gulf oil exports are back to 81% of pre-war levels, led by Saudi Arabia. Only 60% of those Gulf barrels are crossing the Strait of Hormuz now against 83% before the war, so the routes are stretched and longer, but the oil is moving and volumes are near where they were. A refiner short of crude would run less, so this could be part of it, though the trend is toward more feedstock reaching market.

Natural gas rules itself out as the pinch. Storage is 3415, up 6.3% and at its 30-day high. Refineries burn gas for process heat and hydrogen, and there is plenty of it in the ground. Nothing about the plants' own energy bill forced them to throttle back.

What the numbers support is narrow and worth saying plainly. Utilization fell 5.6% while the crack spread held near 59, which means refiners did not pull back because the business went bad. They are making good money per barrel and the capacity loss is coming from somewhere other than price, most likely the seasonal maintenance the calendar and the wire both point to. I cannot tell you from this data how much of the 5.6% is planned turnaround and how much is unplanned outages, because I do not have a crude feedstock price or an outage tally in front of me. The drop looks like maintenance against strong margins, and I would hold that loosely until a crude number confirms it.

For an operator the useful part is diesel. Diesel is up 14.0%, the retail-wholesale spread widened by 0.523, and Goldman sees the tightness lasting into 2027. If you buy diesel, this is the fuel to lock where your supplier will let you, and the wide crack is the thing to watch, because as long as refiners clear near 59 they have reason to bring capacity back and chase that diesel demand once turnarounds finish. Gasoline looks easier. Wholesale RBOB is down 5.5%, so the retail gasoline rise may ease as that lower wholesale cost works through to the pump, assuming the retail margin does not hold on to the gap.

What I am sure of is that the utilization drop is not a sign of refiners in trouble. What I am less sure of is the exact cause of the capacity that came offline, and I would want a crude price and a maintenance schedule before calling it anything more than seasonal.

And that was just the data. See you tomorrow.