U.S. Diesel Prices Surpass $6.50 per Gallon for the First Time
According to Bloomberg, the national average price of diesel in the U.S. rose to $6.505 per gallon on September 21, surpassing the $6.50 mark for the first time, signaling the ongoing transmission of war-driven fuel costs to the real economy.
Diesel prices have surged rapidly over the past month: the national average was about $5.85 on September 4, first breaking the $6 mark on September 11 at $6.05; it further increased to $6.23 on September 14, reaching $6.505 by September 21. Compared to the benchmark price of about $3.70 per gallon before the conflict, the year-on-year increase is between 60% and 69%. During the same period, the national average gasoline price was about $4.29 per gallon, also significantly higher than the pre-conflict level of about $2.90 per gallon, having briefly surpassed $4.50 in May this year.
The increase in diesel prices is significantly faster than that of crude oil itself: current diesel supply is only about 25% of pre-conflict levels, a much larger decline than the approximately 45% drop in crude oil. Two fronts are simultaneously squeezing supply—one is the military confrontation between the U.S. and Iran over the Strait of Hormuz, which accounts for about 20% of global oil transport; the other is Ukraine's ongoing drone strikes against Russian refineries, leading to a drop in Russian diesel exports to a multi-year low. U.S. domestic diesel inventories currently stand at 106.3 million barrels, 13% lower than the five-year average, and are under pressure due to high demand ahead of the autumn harvest season.
During the same period, Brent crude was priced at $104.77 per barrel, and WTI crude has repeatedly surpassed $100 this year, providing synchronous support for rising diesel costs.
Estimates from Brown University indicate that since the outbreak of the Iran conflict, the rise in diesel prices has added over $46 billion in fuel costs for U.S. consumers. Fuel costs typically account for 25% to 30% of the operating costs for trucking companies, and increases in diesel prices will first reflect in the Producer Price Index (PPI) before gradually transmitting to the Consumer Price Index (CPI), forming a typical chain of "diesel rises first, inflation follows."
The most directly impacted are transportation-intensive industries—trucking, rail freight, aviation (pressure on jet fuel distribution), food distribution, building materials supply, and agricultural harvesting operations—all face significant increases in fuel costs that are difficult to fully pass on to end customers; analysts point out that if companies cannot pass on costs, the profit margins and stock prices of related companies will be under pressure. In contrast, energy and refining companies with diesel inventory or refining capacity advantages benefit from the widening price gap, highlighting the funding distribution pattern of "those who stock oil benefit, those who use oil bear the pressure" in this round of shocks.
The autumn refinery maintenance season is approaching, and if the operating rate declines further from the current inventory level, which is already 13% below the five-year average, the upward pressure on diesel prices may further intensify, which is also a key variable for the market to track going forward.
Source: Public Information
ABAB AI Insight
The surge in diesel prices due to war impacts is not new—during the Gulf War in 1990, Iraq's invasion of Kuwait led to a disruption in Middle Eastern oil supplies, causing diesel and heating oil prices to double within months; similarly, at the onset of the Russia-Ukraine conflict in 2022, European diesel prices hit historic highs due to restricted Russian exports. What is different this time is that the shock comes from two simultaneous fronts—the U.S.-Iran military confrontation in the Middle East and Ukraine's drone strikes on Russian refineries, both compressing global diesel supply. This combination of "dual-front conflicts impacting the same fuel category" is relatively rare in nearly thirty years of energy history and is the direct reason for the significant increase in diesel prices (year-on-year increase of about 60% to 69%) compared to crude oil itself (about 45% supply loss).
The flow of funds and resources is undergoing a structural shift—transportation-intensive companies (trucking, rail, aviation, food distribution) are forced to allocate a larger proportion of cash flow to fuel procurement, squeezing funds available for expansion, equipment upgrades, or employee salaries; meanwhile, energy companies with refining capacity and diesel inventory are gaining excess profits from the widening price gap, effectively transferring funds from downstream transportation and consumption to upstream refining and energy asset holders. The $46 billion in additional consumer spending calculated by Brown University essentially quantifies the scale of this resource redistribution.
The current stage of the diesel market is more akin to the simultaneous shortages of diesel and heating oil during the 1973 oil embargo, rather than conventional seasonal supply-demand fluctuations—at that time, geopolitical factors directly cut off the supply chain of specific fuel categories, rather than being solely due to rising demand. The industry is currently in a "structural supply damage period": diesel inventories are already 13% below the five-year average, and we have not yet entered the peak autumn maintenance season, meaning that even if the conflicts do not escalate further, supply recovery will require multiple steps, including refineries operating at full capacity and the arrival of import replacements, making it difficult to quickly return to pre-conflict levels in the short term.
Essentially, this represents a restructuring of the supply chain—when two independent wars simultaneously cut off the supply chain of the same fuel category, the pricing mechanism for diesel shifts from being a "simple derivative of crude oil prices" to an "independent geopolitical risk asset." Its price volatility and duration will no longer fully follow crude oil trends, but will be determined by specific damaged nodes in the supply chain (Russian refinery capacity, Strait of Hormuz passage capacity). Mechanistically, this means that as long as these two specific nodes remain unrepaired, the premium of diesel relative to crude oil will continue to exist, and the transmission path from PPI to CPI will be faster and more direct than conventional oil price increases, because diesel is embedded in every segment of the real economy, including transportation, agriculture, and construction, making it the least frictional and fastest penetrating link in the inflation transmission chain.
ABAB News · Cognitive Law
- When two fronts impact the same fuel, the increase will no longer synchronize with crude oil.
- Where diesel rises first, prices will eventually follow.
- Those who stock oil benefit from the price difference, while those who use oil bear inflation.