US inflation accelerated to 3.7 percent in September, surpassing economists’ forecasts and marking the first increase in annual inflation since May. The rise was largely driven by a significant rebound in fuel prices, which surged amid ongoing geopolitical tensions related to the conflict in Iran. The data was released weeks ahead of the US midterm elections, raising concerns about the economic pressures facing consumers, particularly those in lower income brackets.

The Consumer Price Index (CPI) increased from 3.4 percent in August and exceeded the anticipated 3.6 percent rise. Core inflation, which excludes the more volatile food and energy sectors, also rose to 2.6 percent from 2.4 percent the previous month, pointing to broader price pressures across the economy. According to the US Bureau of Labor Statistics, petrol prices climbed 34.2 percent year-on-year and were 9.1 percent higher than in August, while diesel prices hit record levels in parts of the country.

The rise in fuel costs has been linked to supply disruptions and uncertainty tied to the ongoing conflict in Iran. The International Energy Agency (IEA) warned that a global diesel shortage is expected to persist into next year, despite international efforts—including attempts by President Donald Trump’s administration—to ease supply constraints. Measures taken by the US have included the release of emergency oil and diesel reserves from the G7, lifting some sanctions on Russian diesel, and proposals to restrict fuel exports domestically.

The inflation increase is complicating the economic landscape ahead of the midterms scheduled for November 3, where control of Congress is at stake. The issue of rising living costs, exacerbated by inflation outpacing wage growth—real wages have declined for six consecutive months with hourly earnings rising 3 percent—has become a focal point in campaigning by both parties. Democrats are seeking to capitalize on voter frustrations with price increases, while the Trump administration faces pressure to curb inflationary pressures and stabilize fuel costs.

Financial markets reacted swiftly to the inflation report. Yields on two-year US Treasury notes briefly rose to 4.95 percent before settling back near 4.85 percent, reflecting heightened expectations of possible Federal Reserve interest rate hikes. Prior to the data release, markets had largely discounted an October rate increase, but futures now indicate roughly a 40 percent probability, up from 22 percent. However, some analysts and Federal Reserve officials have cautioned against immediate action, suggesting that the central bank may wait for more data given the proximity to the elections.

Economists and investment strategists observe that inflationary pressures are becoming more entrenched. Industry experts note that price increases are now evident in many parts of the consumer basket, signaling a broadening of inflation beyond energy costs. The situation poses a challenge for policymakers balancing the goals of controlling inflation without derailing economic growth in a politically sensitive period.