Why has the diesel retail-wholesale spread narrowed to 1.356 this month?

The spread, the per-gallon gap between what a retailer pays at the rack and what the pump charges, is 1.356 now, down 0.283 over the past 30 days. That gap is the retailer's gross margin on every gallon of diesel sold. A quarter and change came out of it in a month. I wanted to know what moved, and whether the retailer or someone upstream is carrying the change.

Start with the pump. U.S. diesel is 6.276, down 3.9% over 30 days from a high of 6.529. Retail eased. But the spread shrank while retail dropped, which means the wholesale cost under it did not fall as much as the pump did. The rack held up and the pump gave a little back, so the retailer's slice is what closed.

So I went to crude, because wholesale diesel tracks it. Brent is 109.47, up 9.1% over 30 days. The 30-day low was 76.01 and the high 109.86, so crude ran most of the way up the range and is near the top of it. Crude climbed hard while the diesel pump eased. A retailer buying at a rack priced off that crude paid more for the barrel behind each gallon, then sold the gallon for slightly less. The margin between the two compressed from both ends.

The crude move itself is not demand doing the pushing. Goldman Sachs says the average global freight rate to move oil has gone to $20 per barrel from $3 per barrel last year, with the Iran war and the Hormuz crisis behind it. RBN Energy reports shipping crude from the U.S. Gulf Coast to China on a VLCC cost more than $80 million earlier this month, double September and 5X a year ago. Freight is landing on the delivered price of the barrel. Goldman keeps a $90 per barrel Brent baseline and calls the freight surge an upside risk to it, and Brent is already above that. The cost of moving the barrel is sitting in the barrel, and the barrel is sitting under the rack.

That explained the wholesale side holding firm. It did not yet tell me whether refiners were widening their own cut while the retailer's narrowed, so I checked the crack. The 3:2:1 crack spread, a proxy for the refiner's margin, is 53.3, down 16.53 over 30 days. It narrowed by a lot more than the retail spread did. Refiners are not expanding their take this month. Their margin came down harder than the retailer's.

The crack fell on the gasoline side, not diesel. RBOB has dropped 11.7% over 30 days to 3.065, down from a high of 3.587. U.S. gasoline at the pump is 4.424, down 4.0%. The 3:2:1 is weighted two parts gasoline to one part distillate, so soft gasoline drags the whole crack down even while diesel stays firm. A refiner heavy on diesel yield is doing better than that 53.3 suggests, but the headline margin still fell.

Supply backs up the firm-diesel read. U.S. refinery utilization is 16.615, off 4.1% over the month from its high of 17.586. Less throughput while diesel demand holds keeps the distillate side tight. The U.S. Department of Energy has called on refiners at home and abroad to raise diesel output, per Reuters citing two department officials, with the national average stuck above $6. The Loadstar reports transport businesses asking for help as diesel hits a record. TradeWinds ties diesel prices to the administration's sanctions stance. Firm diesel is the backdrop to all of it, and firm diesel is what keeps the rack from falling with the pump.

So here is what I am sure of. The retailer's diesel margin narrowed because the wholesale cost under it held up while the pump eased, and the wholesale cost held up because crude climbed 9.1% on freight, not because retailers or refiners widened anything. Crude and shipping took the move. The refiner crack fell further than the retail spread, so refiners are not the ones who gained ground this month. The per-gallon margin is landing at 1.356 for the retailer, down from where it was, and the dollars that left it went up the chain toward the delivered barrel.

Where I am less sure is the refiner picture. The 53.3 crack is a blended number dragged by weak gasoline, and a diesel-long refinery may be earning more off distillate than that figure shows. I cannot separate the two from the data in front of me, so I will not pretend the crack tells the whole refiner story. It tells the blended one.

For an operator, the useful part is plain. The 1.356 is thinner than last month, and the thing that thinned it is a crude and freight move you do not control. If freight stays elevated, as Goldman expects near term, the rack may keep the pressure on retail margin until the pump catches up or crude backs off. Watch the freight rate and watch Brent against that $90 baseline. Those are the two numbers moving your spread.

And that was just the data. See you tomorrow.