Diesel's retail-to-wholesale margin narrowed 37 cents a gallon even as pump diesel sits near a month high

Retail diesel is 5.599 today, at the 98 percent mark of its 30-day range (low 3.459, high 5.652). That is about as high as pump diesel has been in a month. But the spread between retail and wholesale is 1.104 now, down 0.367 over the past 30 days. So even with the pump number near its ceiling, the cents you keep between rack and street has thinned by roughly 37 cents a gallon over the month. If you have been reading the high pump price as a fat margin, check the ticket. The buy side rose faster than you could pass it through.

The reason is on the wholesale side. ULSD diesel futures are 4.54, at the 91 percent mark of their range (low 3.093, high 4.682), up 16.3 percent in 30 days. Crude is pulling the whole barrel up with it: WTI is 91.48, up 17.0 percent, and Brent is 96.28, up 15.2 percent. Your cost of goods climbed most of the way to a month high while the pump price ran into resistance near the top of its own range. That gap is the squeeze.

The 3:2:1 crack spread is 62.09, up 2.05 over the month, so the refiner's take on turning a barrel into product is a little wider than it was. Refining margin widened while your street margin tightened. Those are two different lines on the same barrel, and right now they are moving in opposite directions.

Diesel futures near 91 percent of range with crude still climbing means your wholesale cost could keep pushing up on the next fill, so watch whether the pump can move with it or whether that 1.104 spread tightens further. If crude stalls, the wholesale side may ease and give the margin room back.