Inflation accelerated across several major economies in September, with energy prices emerging as the primary driver of price increases worldwide.
In the United States, the consumer price index rose 3.7 percent year-over-year in September, exceeding economist expectations of 3.6 percent, according to data released Wednesday by the Bureau of Labor Statistics. The monthly increase stood at 0.6 percent, matching forecasts. Gas prices, which rose 9.1 percent in September, accounted for more than half of the monthly inflation increase. Energy prices overall climbed 5.2 percent last month, up from 2.1 percent in August. A gallon of regular gasoline cost roughly $4.33 as of Wednesday morning. The annual inflation rate of 3.7 percent marked the highest level since May, when it reached 4.2 percent.
Portugal recorded inflation of 3.6 percent in September on a year-over-year basis, up from 3.3 percent in August, according to data released Tuesday by the Instituto Nacional de Estatística. The acceleration was driven largely by fuel prices. Energy product prices rose to 15.3 percent from 12.2 percent the previous month. Unprocessed food prices accelerated to 3.7 percent from 3.4 percent. Core inflation, excluding energy and unprocessed foods, reached 2.7 percent, up from 2.6 percent in August.
Spain's inflation climbed to 4.9 percent in September, the highest level recorded since February 2023, according to the Instituto Nacional de Estadística. The increase of six-tenths of a percentage point from August was primarily attributed to fuel price increases stemming from the energy shock caused by the Iran conflict, combined with a base effect from fuel price declines in September 2025. The government maintained a 20-cent-per-liter tax reduction on diesel and gasoline to contain the rise at fuel pumps. Core inflation, excluding energy and unprocessed foods, stood at 3.1 percent year-over-year.
In Argentina, inflation reached 1.9 percent in September, accelerating 0.2 percentage points from August's 1.7 percent, according to the Instituto Nacional de Estadística y Censos. Year-over-year inflation stood at 33.4 percent, while the accumulated rate for the first nine months of 2026 reached 23.6 percent. Regulated and seasonal prices rose above core inflation during the month. Housing, water, electricity, gas and other fuels led increases, followed by education at 3 percent, communications at 2.5 percent, health at 2.4 percent, and food and non-alcoholic beverages at 2 percent. Seasonal prices, driven primarily by vegetables, tubers and legumes, recorded the largest monthly increase at 2.9 percent.
In Cape Verde, inflation rose to 2.7 percent year-over-year in September, up 1.6 percentage points from August, according to the Instituto Nacional de Estatística. The monthly rate of change reached 1.1 percent, 1.2 percentage points higher than the previous month. The twelve-month average inflation rate stood at 1.5 percent. Core inflation, excluding energy and unprocessed foods, registered a year-over-year change of 1.5 percent, up 1.2 percentage points from August.
Across these economies, energy costs remained the dominant factor in price acceleration, with fuel prices and utility tariffs driving the majority of monthly increases. Officials attributed the global energy price surge to ongoing geopolitical tensions, particularly the conflict involving Iran.