Why has RBOB gasoline fallen 10.7% in a month while diesel climbed?

RBOB gasoline is $3.026, down 10.7% over the past thirty days, off a high of $3.772. Nearly every headline on my wire this month says refined products are getting more expensive. So why is gasoline moving the other way?

The first thing to rule out is crude. If gasoline fell because the barrel fell, the question answers itself and there is nothing more to look at. But crude is firm. Brent was $91.53 and WTI $85.47 in the latest tally, a fourth straight day of gains, with Murban at a four-month high as ADNOC curbs supply to Asia and tanker traffic through the Strait of Hormuz slows. Crude rising while gasoline falls means the drop is not coming from the barrel.

Diesel makes the split plain. U.S. diesel is $5.454, up 6.2% over the same thirty days. ULSD futures are $4.336, up 5.3%. The two big products went opposite ways in the same month, distillate up and gasoline down. Whatever pulled gasoline lower did not touch diesel.

The wire explains the diesel side cleanly. Ukrainian strikes on Russian refineries have knocked out processing, triggering motor oil shortages and price spikes inside Russia and forcing a fuel exporter to import from Asia. RBN has declining Russian refinery output pushing global products prices higher and shifting trade flows. A drone attack damaged an oil processing unit at the Ufa complex. That kind of damage lands on distillate, the diesel and jet side of the barrel, which is why diesel is bid and gasoline is not.

So gasoline is doing its own thing, and the reasons look domestic. U.S. petroleum inventories are 424.41 million barrels, up 3.6% on the month. More barrels in tank means less reason to bid the product up. The calendar matters too. This is mid-August, the back end of the summer driving season, when gasoline demand eases and the market starts pricing the shoulder months. I can't put a number on the seasonal piece from what is in front of me, but the direction fits a market with ample supply and softening demand.

Refinery activity points the same way. U.S. refiners are absorbing over half of Venezuelan crude, and Gulf Coast crude exports rose 20% week-over-week to 3.6 MMb/d, with Enterprise Houston loadings up 21% to 786 Mb/d. Refiners are running hard and moving barrels. Hard runs keep gasoline supply comfortable at the same time the war premium is landing on distillate.

Now the crack spread, which ties the month together and also throws up the one thing I can't square. The 3:2:1 is $60.53 now, down 8.8 over thirty days. The 3:2:1 weights gasoline twice for every barrel of diesel, so a 10.7% fall in RBOB pulls the blended margin down even with diesel up 6.2%. Gasoline is the reason the refiner's headline margin narrowed. And yet the wire also carries "cracks test records" on the Gulf as refiners take in Venezuelan crude. A record crack in one headline and a 3:2:1 down 8.8 on my desk do not fully reconcile. The record language may be a single-grade or single-region crack rather than the blended benchmark, but I can't confirm that from what I have, so I'm flagging it rather than smoothing it over.

For a retailer, the practical read is straightforward. Wholesale gasoline near $3.026, off a $3.772 high, means the cost of the next load coming in is lower. Street prices tend to lag the wholesale move down, so gasoline margins may widen for a few weeks while the pump catches up. On diesel it is the mirror image. The retail-wholesale diesel spread is $1.017, up just 0.002 on the month, basically flat, so diesel margins are steady while the wholesale cost of the product keeps climbing. Any operator with freight exposure or a diesel-heavy book carries that higher cost rather than earning on it.

What I'm sure of: gasoline did not fall because crude fell, because crude rose. It fell for reasons sitting on the gasoline side of the market: inventories are comfortable and refiners are running hard and exporting, and the driving season is winding down. The tightness from the Russian refinery hits went into distillate instead. The two products decoupled this month, and the 3:2:1 fell because the heavier gasoline weighting dragged it down even as diesel climbed.

What I'm not sure of: how much of the 10.7% is seasonal versus supply. Mid-August softening and a 3.6% build in inventories both point the same direction, and I can't cleanly separate them with the data on hand. I'm also not able to reconcile the record-crack headline with our blended spread falling, and I would rather say that plainly than pick the version that reads neater.

For now the useful takeaway for an operator is simple. Cheaper wholesale gasoline is a chance to hold margin at the pump, and pricier wholesale diesel is a cost to manage on the freight side, with the split driven by where the world's refinery trouble actually landed. If crude keeps grinding higher on Hormuz and the Russian outages drag on, the distillate side is the one to watch, not gasoline.

See you tomorrow.