Diesel's street margin is 145.6 cents a gallon, about 13 cents wider than a month ago

The diesel retail-wholesale spread is 1.456 now, up 0.133 over the past 30 days. The markup between what you pay at the rack and what you charge at the pump has widened by about 13 cents a gallon. Wholesale came down faster than street price, so anyone selling diesel is keeping more of each gallon right now than they were in mid-September.

The reason is on the futures side. ULSD is 4.65, down 11.4% over 30 days, and it is at the 70 percent mark of its 30-day range between 3.238 and 5.262. Wholesale diesel has eased, but retail is sticky the way it usually is, and the gap between the two is where the extra margin showed up. If you haul or jobber diesel, this is the part of the board that actually touches your invoice today. Gasoline tells a quieter story: RBOB is 3.072, down 11.8%, and it is only at the 38 percent mark of its range, so pump-side gas margin has less room to work with than diesel does.

One thing worth watching is the 3:2:1 crack spread, which is 54.93 now, down 13.67 over 30 days and tighter. The crack spread is the refiner's margin on turning crude into product, and it has narrowed hard while the street spread widened. If refiners feel that squeeze, wholesale diesel could firm back up in the coming weeks, which may start to close the gap you are enjoying now. Nothing here says it has to happen, and WTI at 96.2 is down 6.1% and sitting high in its own range, so crude is not pushing product up at the moment. For now the read is simple: the diesel margin is working in your favor, and the futures that feed it are soft.