Diesel's retail-wholesale spread is 1.654, about 35 cents wider than a month ago

The diesel retail-wholesale spread is 1.654 a gallon, up 0.354 over the past 30 days. That is about 35 cents of added room between what you pay at the rack and what you charge at the pump, and it is money sitting on your side of the counter. If you move a few thousand gallons of diesel a week, that swing is real cash, not rounding.

The wider street margin tracks a wider refining margin. The 3:2:1 crack spread is 63.88, up 2.82 over the month. Gasoline is 4.496 a gallon and near the top of its 30-day range, at the 92 percent mark, even though WTI crude fell to 90.73, down 5.5 percent. Pump prices held up while the barrel came off. Refiners see that spread first, and it is flowing down to the street.

Refinery utilization is 92.7, down 5.2 percent, and it is at the 44 percent mark of its 30-day range. Watch that number. Lower runs mean less product coming out, and if utilization keeps slipping while demand holds, wholesale diesel and gasoline could firm up and close some of the margin you have today. Natural gas is the other mover, with Henry Hub at 3.13, up 10.9 percent over the month, so anything you run on gas is getting more expensive to operate.

For now the read is simple. Your buy side on crude eased, your sell side on fuel held near its highs, and the spread between them widened across both diesel and the refined barrel. Price your contracts against the margin you actually have this week, because a further drop in refinery runs may pull it back in.