The annual inflation rate in the US rose to 4.2% in May 2026, marking its highest level since April 2023, from 3.8% in April and in line with market expectations. This represents the third consecutive monthly acceleration in headline inflation, with energy costs jumping 23.5% (vs 17.9% in April), due to the energy shock triggered by the conflict with Iran. Gasoline prices soared 40.5%, after a 28.4% gain. Fuel oil also increased 58.9% (vs 54.3%). In addition, inflation accelerated once again for shelter (3.4% vs 3.3%) and food (3.1% vs 2.3%). Compared to the previous month, the CPI was up 0.5%, slightly less than 0.6% in April, and in line with forecasts. Energy prices rose 3.9% and accounted for over 60% of the monthly gain. Meanwhile, the annual core inflation rate went up to 2.9%, a new high since September 2025, compared to 2.8% in April and matching forecasts. Compared to the previous month however, the core CPI rose 0.2%, less than 0.4% in April and below forecasts of 0.3%.