A Short-Lived Shock, a Slower Decline The sequence observed between September 11 and September 22, 2026 looks like a round trip, but it is not one. On September 11, a barrel of Brent traded at ?.06

A Short-Lived Shock, a Slower Decline

The sequence observed between September 11 and September 22, 2026 looks like a round trip, but it is not one. On September 11, a barrel of Brent traded at ?.06. In two sessions, it gained ?.74 to reach ?.80 on September 15, a rise of 10.79%. The correction was immediate: ?.84 on the 16th, ?.18 on the 17th, then a steady slide to ?.89 on September 22.

Since the peak, Brent has lost ?.91, or 12.16%. It ends the period 2.69% below its September 11 level. The spike has therefore been entirely erased in value, but the absolute level remains high: a barrel near ? still weighs heavily on energy budgets.

WTI Falls Back Below ?

U.S. crude followed the same profile, with a smaller amplitude. WTI went from ?.27 on September 11 to ?.02 on the 15th, a gain limited to 5.68%. It then fell 9.91% to close at ?.41 on September 22. The symbolic ? threshold was breached to the downside as early as September 21, at ?.97. Over the entire period, WTI gives up 4.80%, a decline markedly sharper than that of Brent.

This asymmetry is reflected in the spread between the two benchmarks. From ?.79 on September 11, the Brent-WTI differential jumped to ?.78 on the 15th, then to ?.22 on the 16th. It then tightened around ? to ?, settling at ?.48 on September 22. The tension therefore bore mainly on the international reference crude. Buyers indexed to Brent absorbed the bulk of the shock, while those tied to WTI enjoyed relative protection.

Refined Products: An Uneven Pass-Through

For an industrial operator, the crude price is merely a leading indicator. The real cost plays out in refined products, whose reaction differs by segment.

Jet Fuel, Locked to Crude

U.S. aviation fuel tracked the crude trajectory. It went from ?.521 per gallon on September 11 to ?.705 on the 15th, a rise of 4.07%. It then fell back to ?.354 on September 22, a decline of 7.46% from the peak. Over the period, jet fuel drops 3.69%, an order of magnitude close to that of WTI. For air transport and express logistics, the decline therefore passes through quickly, with no significant retention in refining margins.

Gasoline, Lagging by Several Sessions

U.S. regular gasoline tells a very different story. While crude peaked on September 15, gasoline continued to climb: ?.834 per gallon on the 15th, ?.869 on the 16th, ?.986 on the 17th, then a peak at ?.038 on September 18. Between the 11th and the 18th, the gain reaches 9.76%, versus 5.68% for WTI between the 11th and its own peak.

The subsequent pullback remained modest: gasoline ends at ?.891 on September 22, down only 3.64% from its high. Above all, it remains 5.76% above its September 11 level, while WTI has fallen 4.80% over the same period. This roughly three-session lag and this downward rigidity illustrate the so-called "rocket and feather" mechanism: pump prices rise fast and fall slowly. For light-vehicle fleets and distribution, the expected relief from the crude pullback is not yet visible in costs.

U.S. Natural Gas: An Autonomous Trajectory

Henry Hub gas moves in a distinct register. Starting at ?.71 per million BTU on September 11, it reached ?.00 on September 16 before stabilizing between ?.90 and ?.97. It closes at ?.90 on September 22, up 7.01% over the period.

This move did not follow the oil decline: gas ends higher while crude ends lower. The amplitude nonetheless remains contained, within a 29-cent range. The ratio between the Brent barrel price and the U.S. gas million-BTU price comes out at nearly 40 on September 22. This considerable gap confirms that U.S. gas remains a cheap energy source relative to petroleum products. For industries able to arbitrage between fuels, the competitive advantage of gas-fired processes in the United States remains intact.

Elasticity of Procurement Costs: What the Data Teaches

This eight-session sequence yields several lessons for managing energy purchases.

First, indexation matters as much as price. A contract tied to Brent absorbed a rise of nearly 11% in two sessions, versus less than 6% for a contract tied to WTI. The widening of the spread to more than ? on September 16 shows that the choice of benchmark can materially alter a supply chain's bill.

Second, the pass-through is neither instantaneous nor symmetrical. Jet fuel tracks crude almost in real time, in both directions. Gasoline amplifies the rise, extends it by several sessions and restores only part of the decline. Cost models that apply a single elasticity to all petroleum products underestimate this retention risk.

Finally, energy diversification acts as a shock absorber. Henry Hub, weakly correlated with the period's oil move, offered relative stability. A mixed energy portfolio would have smoothed the impact of the mid-September spike, even though gas did not benefit from the pullback.

Points of Vigilance for the Coming Weeks

The violence of the September 15 spike is a reminder of the market's capacity to abruptly price in a risk premium. Brent's return to around ? does not mean normalization: levels remain high and daily volatility, which exceeded ? in a single session on Brent, argues for more active hedging strategies.

Three indicators warrant close monitoring: the Brent-WTI spread, a revealer of tensions in the international market; the speed of the gasoline pullback, which determines the effective decline in road transport costs; and Henry Hub's hold around ?, a threshold already touched on September 16. For industrial buyers, the lesson of this fortnight is clear: the cost of energy depends less on the level of crude than on how each link in the chain transmits its variations.

This article was written with the assistance of artificial intelligence and verified by our editorial team.