U.S. wholesale prices surged last month as the Iran war drove up the cost of energy.

The Labor Department reported Tuesday that its producer price index — which measures inflation before it hits consumers — rose 0.5% from February and 4% from March 2025. The year-over-year gains was the biggest in more than three years. Energy prices surged 8.5% from February.

Excluding volatile food and energy prices, so-called core producer prices rose a modest 0.1% from February and 3.8% from a year earlier.