CNN  —  Wholesale price inflation unexpectedly accelerated in June to its highest rate since March 2023. That’s an unwelcome development for the US economy one day after the government announced that consumer prices declined on a monthly basis for the first time in four years. The Producer Price Index, a measurement of average price changes seen by producers and manufacturers, was 2.6% for the 12 months ended in June, unexpectedly rising from the 2.4% annual rate seen in May, according to Bureau of Labor Statistics data released Friday. On a monthly basis, prices rose 0.2% after holding flat in May. Economists had expected that prices would increase 0.1% on a monthly basis and hold steady at 2.2% annually. PPI serves as a potential bellwether for retail-level inflation in the months ahead.