The middle-distillate bottleneck as the carrier of the 2026 shock into inflation: the United States, Europe and Türkiye, August–September 2026
ABSTRACT
This analysis examines through which product the 2026 energy shock reached consumer prices. It argues that, in price terms, the shock concentrated in diesel rather than crude: the IEA reports diesel above $200 a barrel in early September, 94% over pre-war levels, and the US Gulf Coast diesel crack spread rose from about $20 to over $100. Crack spreads, refinery utilisation and Gulf product exports are compared, and pass-through is traced in US August CPI and Turkish pump prices. The bottleneck has three sources: a roughly 60% fall in Gulf product exports, Russia’s diesel export ban and Atlantic refineries at capacity. US headline effects came from gasoline; diesel works through freight and production costs and can carry pressure into 2027.
1. The event and its measured effect
While crude oil fluctuated around $100 in September 2026, the product market priced a much sharper scarcity. On 11 September New York Harbor ultra-low sulphur diesel (ULSD) stood at $211.51 a barrel against $100.72 for WTI, and the simple ULSD–WTI crack spread had widened from $61.43 on 1 June to $110.79 (OilPriceAPI, 2026). The refiner’s gross margin on diesel exceeded the price of crude itself.
The claim is that, measured by price, the carrier of the 2026 shock was the bottleneck in middle distillates (diesel, gasoil, jet fuel and heating oil). For inflation, the diesel channel is less visible to households than the gasoline channel but spreads through freight, farm and industrial costs into a wider basket and over a longer period. The scope is August–September 2026, with data for the United States, Europe and Türkiye and for losses at Gulf refineries. The futures–physical crude gap and the event-level crude price path are outside the scope.
2. Concepts: crack spreads and pass-through
A crack spread is the difference between the price of a refined product and the price of crude, and it measures the scarcity value of refining. If crude supply alone is cut, the spread should stay roughly constant; a widening spread shows that scarcity has formed in the refined product or in product trade.
Two studies guide the pass-through question. Kilian and Zhou (2022) show that rising oil and gasoline prices from 2020 onwards markedly raised US headline inflation and households’ one-year inflation expectations. Households buy gasoline directly and see its price daily; diesel is mostly a business input whose effect runs through costs. Choi et al. (2018), using 72 economies, find that a 10% rise in global oil inflation raises domestic inflation by about 0.4 percentage points on impact, similarly in advanced and developing economies, with cross-country differences most consistently explained by transport’s CPI share and energy subsidies. For Türkiye, Çatık and Önder (2011), using a regime-switching model on 1996–2007 data, show that oil price pass-through becomes asymmetrically stronger in the high-inflation regime. These findings predict a larger inflation effect of the same diesel shock in Türkiye than in the United States.
3. Mechanism: three sources of the bottleneck
The first source is Gulf refining. According to the IEA, Gulf product exports fell by about 60% from their February level, and global refinery runs, although at a summer peak of 81.4 million barrels per day (mb/d) in August, were 4.2 mb/d lower year on year (International Energy Agency [IEA], 2026). After the attack on the East–West pipeline, the 400,000 b/d SAMREF refinery at Yanbu cut operations by 50% and is expected to run at reduced capacity at least through October (Industrial Info Resources, 2026).
The second source is trade restriction. Argus estimated that 1.3–1.4 million barrels a day of diesel were missing from the global market in early September, and Russia’s diesel export ban had been extended to 30 September (International Association of Movers [IAM], 2026). The Gulf loss and the Russian restriction hit the same product group.
The third source is the capacity limit in the Atlantic basin. US refinery utilisation reached 98% in early September (Watson, 2026) and stood at 96.8% on 17 September, when US distillate stocks were 13% below their five-year average (Charles, 2026). The EIA expects US distillate stocks to fall below 100 million barrels in September and to stay below the five-year average for most of 2027 (Hydrocarbon Engineering, 2026). The constraint sits in refining and inventories and would outlast a recovery in crude flows.
4. Price evidence: crude and diesel diverge
| Indicator | Earlier level | September 2026 level | Source |
|---|---|---|---|
| US Gulf Coast diesel crack spread | About $20/bbl before the conflict | Above $100/bbl on 1 September | Watson (2026) |
| US Gulf Coast ULSD crack spread | August average $92.84/bbl | $107.26/bbl (17 September) | Charles (2026) |
| NY Harbor ULSD–WTI crack spread | $61.43/bbl (1 June) | $110.79/bbl (11 September) | OilPriceAPI (2026) |
| Southern Europe diesel crack spread | — | $104.08/bbl (2–4 September) | IAM (2026) |
| US on-highway diesel | — | $6.285/gallon, +68% year on year (17 September) | Charles (2026) |
Diesel prices 94% above pre-war levels (IEA, 2026) and the widening of crack spreads show that product scarcity formed a price component separate from crude. US retail diesel set a record of $5.85 a gallon on 4 September (Watson, 2026). On 17 September Brent futures fell intraday to $104 while refiners kept their diesel edge (Charles, 2026); a margin that stays high while crude eases shows that the two markets were responding to different scarcities.
5. Where the effect actually sits: gasoline directly, diesel through costs
US August CPI separates the two channels. Headline CPI rose 3.4% year on year, gasoline 27.4%, energy 16.3% and fuel oil 52.0%, while core CPI stayed at 2.4%. The 3.9% monthly rise in gasoline accounted for more than a third of the total monthly increase (U.S. Bureau of Labor Statistics [BLS], 2026). This limits the claim: in the United States the direct headline contribution came from gasoline, with its large basket weight. The 52% rise in fuel oil, the middle distillate households buy directly, shows how sharply diesel scarcity registered where it is visible.
Diesel’s main channel runs through costs, and the August data do not yet show it clearly in core inflation. Read with Kilian and Zhou (2022), diesel’s effect is likely to be weaker than gasoline’s in household expectations and more persistent in firms’ pricing decisions.
In Türkiye the diesel channel is more directly visible. In August transport prices rose 4.82% month on month and 35.08% year on year, above headline CPI inflation of 31.51% (Dünya, 2026). The special consumption tax (ÖTV) on diesel was cut to zero on 13 August; Minister of Treasury and Finance Şimşek cited the burden of high diesel prices on consumers and producers, and a rise to TL 3 in September was scheduled (GZT, 2026). On that day diesel cost TL 80.07 per litre on Istanbul’s European side; on 22 September it reached TL 96.30, well above petrol at TL 80.40 (GZT, 2026; Hisse.net, 2026). With the tax increase in this period limited to TL 3, most of the TL 16.23 rise at the pump came from the product price, not from tax. Choi et al.’s (2018) transport-share finding and Çatık and Önder’s (2011) high-inflation-regime result make stronger propagation in Türkiye the expected outcome.
6. Alternative explanations considered
One alternative attributes the Turkish diesel rise to the exchange rate. The lira can explain part of the pump price level, but it cannot explain diesel’s divergence from petrol, because the exchange rate affects both products in the same proportion. The divergence points to distillate scarcity.
A second alternative holds that diesel simply followed crude. The crack spread data rule this out as a full explanation: a margin that rose from about $20 to above $100 (Watson, 2026) and held while crude eased (Charles, 2026) is a component that crude does not contain.
7. Outlook: Türkiye, Saudi Arabia and the World
In Türkiye the first October data point is September CPI, due from TurkStat on 5 October; the September expectation in the CBRT Survey of Market Participants is 2.12% (Uzmanpara, 2026). The diesel ÖTV schedule sets TL 6 in October, TL 9 in November, TL 12 in December and TL 13.9006 on 1 January 2027 (GZT, 2026), adding a mechanical monthly increase regardless of international prices. If crack spreads stay above $100, tax and product price push the same way; if they fall, the schedule absorbs part of the decline. Under either condition diesel should remain a principal driver of transport inflation in the fourth quarter.
For Saudi Arabia, product losses recover more slowly than crude: SAMREF is expected to run at reduced capacity at least through October (Industrial Info Resources, 2026), on a repair timetable separate from pipeline flows. As long as Gulf product exports remain about 60% down (IEA, 2026), Saudi product export revenue will lag the recovery in crude.
Globally, two schedules matter: Russia’s diesel export ban had been extended to 30 September, and its October status is not confirmed in the sources used here (IAM, 2026); an extension would sustain the European premium. The EIA’s expectation that US distillate stocks stay below the five-year average for most of 2027 (Hydrocarbon Engineering, 2026) implies that the diesel premium can carry into 2027 even if crude falls. Central banks would then be premature in reading lower crude prices as disinflation.
8. Conclusion
The price magnitude of the 2026 shock appeared in diesel rather than in crude. Crack spreads above $100 came from a roughly 60% fall in Gulf product exports, Russia’s export ban and Atlantic refineries running at capacity. Pass-through depended on the economy: in the United States gasoline supplied the direct headline contribution and diesel’s effect accumulated in fuel oil and costs; in Türkiye diesel diverged from petrol and lifted transport inflation above the headline rate. Because distillate stocks are expected to stay low into 2027, easing crude prices will not by itself end the inflation pressure in the diesel channel.
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Furkan Mahmut Tameroglu