US consumer prices rise 0.4% in August as energy costs jump

US consumer prices rose 0.4% in August 2026 on a seasonally adjusted basis, following a 0.1% gain in July, the Bureau of Labor Statistics reported on 11 September. The 12-month inflation rate was 3.4%, unchanged from July.

What happened

Energy was the standout. The energy index climbed 2.1% over the month and 16.3% over the year, and gasoline rose 3.9% in August and 27.4% from a year earlier. Food prices were up 0.1% for the month and 2.7% for the year, and shelter rose 0.3% in the month and 3.0% over twelve months.

Core inflation, which excludes food and energy, rose 0.3% on the month and 2.4% on the year, slightly down from 2.5% in July. In other words, the headline figure was being driven mostly by fuel rather than by broad price increases across the economy.

Why it matters for traders

A split between headline and core inflation makes the market debate harder, not easier. Some participants focus on the headline rate because it affects households directly, while central banks often give more weight to underlying measures and to expectations. The result is that a CPI release can trigger large moves in the dollar, Treasury yields, gold and equity indices, with direction depending on how the numbers compare with what the market had priced in rather than on the numbers alone.

CPI day is one of the busiest moments on the calendar. Spreads often widen for a short period, slippage on market orders is more likely, and tight stops can be hit by volatility that fades within minutes. Traders with leveraged positions open through the release should consider whether their margin can handle a sudden gap.

Energy-driven inflation also links markets together: oil and fuel prices feed the inflation data, the data shapes rate expectations, and rate expectations feed back into currencies and indices.

What to watch

• The next CPI release date on the BLS schedule, and the breakdown between energy and core components.
• Central bank commentary on whether energy-led inflation is spreading into wages and services.
• Oil and gasoline prices, which feed directly into the headline figure.