“Core” C.P.I., which more closely reflects underlying inflation by removing volatile food and energy prices, also showed little improvement. It rose 0.4 percent from December or 3.3 percent on a year-over-year basis, both higher than economists expected. The monthly increase in core prices was the highest since April 2023.

Inflation rose to 3% in January, its highest rate for six months, and above the 2.9% expected by economists. Price rises for food and energy both helped drive up the overall rate of price increases. The rise comes weeks after the US central bank decided to hold interest rates,