Diesel's street margin narrowed about 72 cents a gallon over the past month

The diesel retail-wholesale spread is 1.015 today, down 0.724 over the past 30 days. That is roughly 72 cents a gallon of street margin gone in a month. If you sell diesel at the pump, you are working on a much thinner cushion over the rack than you were four weeks ago, and the reason is on the wholesale side.

ULSD futures are 4.026, up 29.8% over the past 30 days, the biggest move of any benchmark on the board. Diesel now trades near the 67 percent mark of its 30-day range, closer to the high of 4.496 than the low of 3.093. Your cost to refill the tank has climbed fast, and retail has not kept pace, which is what pulled the spread in. Crude backs up the diesel story without matching it: Brent is 89.99, up 24.0%, and WTI is 83.74, up 21.0%, both still in the lower half of their 30-day ranges.

Refiners are on the other side of that squeeze. The 3:2:1 crack spread is 60.74, wider by 7.41 over the past month, so the margin to turn a barrel of crude into product is up while the margin to sell diesel on the street is down. Gasoline is the quieter leg here, with RBOB at 3.147, up 11.4%, sitting at the 39 percent mark of its range. Natural gas is the outlier going the other way, down 14.6% to 2.8, with storage now at 99.776 and near the top of its 30-day range at the 98 percent mark.

If diesel futures hold near 4 and retail stays where it is, that street spread could stay tight into next week, so it may be worth checking your pump price against the rack more often than usual until wholesale settles.