Diesel's retail margin narrowed 37 cents to $1.104 a gallon as wholesale outran the pump

The retail-wholesale diesel spread is $1.104 a gallon, down over the past 30 days. The spread is the margin between the rack price you pay and the pump price you charge, and it got thinner. If you move a few thousand gallons a day, that is real money off the top.

The reason is in the two diesel numbers. Wholesale ULSD futures are at 4.505, up 19.5% in 30 days and sitting near the top of their range at the 89 percent mark. The pump price, U.S. diesel at 5.599, is up only 4.7% over the same stretch. Wholesale climbed about four times as fast as retail, and the difference in those rates pulled the spread in. Crude is behind the move: WTI is at 92.78, up 22.4% in 30 days, with Brent at 97.08 on a nearly identical 22.3% run.

So the pump looks high and it is high, but the cost side rose faster than the street price could follow, and the margin paid for the difference.

The pump price is now at the 98 percent mark of its 30-day range, just under its high of 5.652, so there is little room left at retail before it prints a fresh 30-day top. If wholesale holds where it is, retail could keep grinding higher over the next week or two as operators try to rebuild the margin they lost. Worth watching whether the rack backs off first, which would let the spread widen back out on its own.