Record diesel refining margins are turning a market signal into a wider cost problem for logistics-heavy industries.
The issue is not only the price of crude oil. Diesel crack spreads — the difference between the value of diesel and the crude oil used to make it — have reached record or near-record levels in several major markets. That matters because diesel sits inside the cost structure of trucking, rail, agriculture, construction, mining, warehousing and delivered inventory.
For businesses already dealing with higher labour, rent, equipment and financing costs, diesel is the kind of expense that spreads quickly. It moves through freight quotes, carrier fuel surcharges, farm operating budgets, jobsite costs and the delivered price of physical goods.
Why diesel margins are under pressure
The U.S. Energy Information Administration said on September 18 that diesel prices are driven by crude oil, retail margins, distribution costs, taxes and crack spreads, which it uses as an indicator of refining margins. EIA said tight global distillate supplies and elevated crude oil prices have pushed diesel higher in recent months.
As of September 14, U.S. retail diesel prices averaged $6.29 per gallon, according to EIA. The agency said that was the highest nominal price since its weekly series began in 1994 and the highest inflation-adjusted price since 2022.
The supply picture is tight even though U.S. refiners are running hard. EIA said U.S. distillate production from January through August averaged 5.1 million barrels per day, the most since 2019, while refinery utilization reached 97% in the week ending September 11. Even so, U.S. distillate inventories were 15.8 million barrels, or 13%, below the 2021–2025 seasonal average.
That is the core tension in the diesel market: refineries are producing more, but inventories are still low because global demand for replacement barrels remains strong. EIA said reduced refining activity in Russia, China and the Middle East has lifted international distillate prices, increased the cost of importing diesel into the United States, and raised demand for U.S. diesel exports.
The crack spread moved from market data to business cost
Reuters reported in August that the U.S. diesel crack spread hit an all-time high of $102.20 per barrel on August 17. The spread crossed $100 per barrel for the first time as supply disruptions collided with peak agricultural demand.
S&P Global also reported that European diesel refining margins reached record levels in early September. Platts assessments cited by S&P Global showed the physical Amsterdam-Rotterdam-Antwerp diesel crack hit $98 per barrel on September 1 before easing to $95.30 per barrel on September 2.
These figures matter because crack spreads are not an abstract refinery metric when they stay high. A wider diesel crack can lift wholesale diesel prices even when crude oil is not the only force moving the market. From there, the cost can move into retail fuel, bulk supply contracts and transportation pricing.
Freight costs respond quickly
Diesel is one of the fastest-moving cost inputs in freight because many carrier contracts include fuel adjustment mechanisms. The U.S. Department of Energy’s ATLAS fuel surcharge table, which applies to shipments using applicable DOE modal rate tenders, listed a 41% less-than-truckload fuel surcharge and an $0.81-per-mile truckload fuel surcharge for September 16 through September 22, based on a September 14 diesel price of $6.285 per gallon.
Those figures do not represent every freight contract, but they show how quickly diesel prices can move through transportation pricing. A higher diesel price does not need to wait for annual contract resets. In many lanes, it can appear in weekly surcharge updates, spot-market quotes or new carrier bids.
The Bureau of Transportation Statistics also includes U.S. diesel sales prices in its latest supply chain and freight indicators, alongside measures such as truck spot rates, inventory-to-sales ratios and freight transportation activity. That placement reflects diesel’s role as a current operating-cost signal, not only an energy-market datapoint.
Agriculture is feeling the pressure during harvest
The timing is especially difficult for agriculture. Reuters reported on September 18 that U.S. farmers are facing record diesel prices during harvest season, when diesel use rises for combines, tractors and crop transport. The same report said the average U.S. diesel price had reached $6.29 per gallon, up 68% from $3.74 a year earlier, based on EIA data.
The pressure is not limited to fuel used on farms. Diesel also moves crops after harvest through trucks, rail and refrigerated food distribution. Reuters cited Michigan State University economist David Ortega, who said higher diesel costs raise expenses throughout the food supply chain, from harvesting to freight delivery.
Rail is another channel. Reuters reported on September 14 that U.S. rail fuel surcharges on grain shipments had more than doubled from a year earlier, citing U.S. Department of Agriculture data. The report said the average fuel surcharge rate on grain shipments reached 48 cents per mile per rail car in the second week of September, up 153% from the weighted average a year earlier.
Those costs do not automatically translate dollar-for-dollar into grocery prices. Retail food prices also depend on labour, packaging, storage, rent, competition, contracts and consumer demand. But elevated diesel raises the cost floor for moving food, especially when it hits during a fuel-intensive harvest window.
Canada is exposed through fuel prices and cross-border freight
Canadian businesses are not insulated from the diesel margin shock. Kalibrate Canada reported that Canadian retail diesel prices rose 6.2 cents per litre in August to 236.8 cents per litre, while the diesel refining margin, or crack spread, reached an all-time high of 119.4 cents per litre on August 19.
Kalibrate’s September 18 daily pump price survey listed the volume-weighted Canada average for automotive diesel at 276.7 cents per litre. Regional prices varied widely, but the national figure shows that Canadian diesel users are also facing elevated costs.
For Canadian carriers, importers, retailers and construction firms, the risk is broader than fuel bought at the pump. Cross-border trucking lanes, U.S.-priced inputs, farm supply chains, rail movements and delivered inventory can all be affected when diesel costs rise across North America.
Why crude prices alone do not explain the problem
Diesel normally moves with crude oil, but crude is only one part of the delivered fuel price. EIA’s diesel price breakdown separates crude oil from refining margins, distribution costs, retail margins and taxes. That distinction is especially relevant when diesel crack spreads are unusually high.
A crude-only view can miss the pressure created by limited distillate supply. If refineries are running near capacity and inventories are still below normal, buyers may bid aggressively for diesel and related middle distillates. That can keep diesel expensive even if crude prices stop rising.
The September Short-Term Energy Outlook from EIA estimated that U.S. average diesel crack spreads would exceed $2 per gallon from August through November before decreasing steadily through mid-2027. That forecast depends on assumptions about normal tanker traffic returning through the Strait of Hormuz and more distillate exports from Saudi Arabia and Kuwait. EIA also said that if flows out of the Middle East remain constrained beyond the end of 2026, global distillate crack spreads would likely be higher than its forecast.
What to watch next
The main signal is whether distillate inventories rebuild. If inventories remain below seasonal averages while global supply stays constrained, diesel margins may stay high enough to keep pressure on freight and operating costs.
The next signals are fuel surcharges, rail rates, trucking spot prices and supplier delivery fees. These are where higher diesel costs become visible to businesses that never buy diesel directly.
The final signal is timing. Agriculture is in a fuel-intensive period, construction projects are still active in many regions, and retailers are moving inventory ahead of the holiday season. A diesel shock during a high-movement period can have a wider effect than the same price move during a slower freight cycle.
Record diesel refining margins are therefore not only a refinery-profit story. They are a logistics-cost story. Until distillate supply improves and inventories rebuild, diesel remains a pressure point for the cost of moving, building, harvesting and delivering goods.
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