US inflation: the March 2026 energy shock, read in the numbers

In March 2026, the US consumer price index jumped to 3.3% year on year, its highest level since April 2024. Almost all the rise comes from energy, propelled by the war in Iran. Beneath this surface, inflation excluding energy and food stayed calm. This distinction is not a technical detail: it is the essential of the analysis.

The March figure

According to the Bureau of Labor Statistics, in its report of 10 April, the CPI rose 0.9% on the month in seasonally adjusted data, after 0.3% in February, taking annual inflation to 3.3% against 2.4% the previous month. The driver is unequivocal: energy rose 10.9% on the month, its strongest monthly rise since September 2005, and gasoline 21.2%, the strongest monthly increase ever recorded since the series began in 1967. On its own, gasoline explains nearly three-quarters of the monthly rise in the headline index.

Beneath the surface, the core stays calm

It is the report’s second figure that says the most. Excluding energy and food, core inflation rose only 0.2% on the month and 2.6% year on year, a tenth of a point below consensus. Housing, the heaviest item in the index, rose 0.3% on the month and 3.0% year on year, its slowest annual pace since August 2021. Food was flat on the month.

The reading that imposes itself is therefore that of a concentrated energy supply shock, not a generalised re-acceleration of prices. The nuance matters because the two situations call for different responses. An oil shock acts like a tax on the consumer: it mechanically weighs on purchasing power, more so on lower-income households for whom gasoline represents a higher share of the budget, but it does not reflect an overheating of demand. In a central bank’s analytical framework, such a shock is treated differently from inflation driven by services or wages.

Why the distinction matters

The risk lies in the transmission. An energy shock, even temporary, can diffuse to the core of the index over six to nine months, as in 2022, through transport and production costs. The favourable scenario has it fade before contaminating the core, which was precisely on the way to moderation before March. The March report does not settle between these two trajectories; it only sets the stakes. For households, the effect is immediate: real hourly wages fell 0.6% on the month. For the Federal Reserve, whose new chair Kevin Warsh argued for lower rates, the rise in inflation combined with a resilient labour market made a quick cut unlikely, markets pricing almost none for 2026.

Update, since March

The shock did not close in a month. Annual inflation kept rising, to 3.8% in April then 4.2% in May, energy remaining the main contributor, joined by a slight firming of housing and tariff effects. The end of the war, sealed by a US-Iran memorandum on 17 June, and the ensuing pullback in oil should lighten the energy component in the coming months. For the source of the shock, see the state of the Strait of Hormuz.

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Primary sources: US Bureau of Labor Statistics, Consumer Price Index (March, April and May 2026 reports); EIA, Short-Term Energy Outlook (April 2026); analyses by the Center for Commercial Agriculture (Purdue) on the transmission of the shock.