The Department of Labor said its Producer Price Index increased a seasonally adjusted 0.6 percent compared with March. The index rose 1.0 percent in March, 0.5 percent in February, and 1.3 percent in January.
The monthly gain was twice what analysts had forecast. The median estimate for the annual gain was 5.9 percent.
The Producer Price Index measures prices received by businesses and it is a successor to what was known as the wholesale price index. It tends to track the better-known Consumer Price Index, which measures prices paid by consumers, but the two inflation gauges can depart from time to time.
The producer price inflation data follows the much higher than expected rise in consumer prices, which sent stocks falling amid concerns that inflationary pressures are strongeer than anticipated.
Excluding food and energy, prices rose 0.7 percent for the month and 4.1 percent for the year, both well-above estimated increases. Excluding food, energy, and trade services (which measure changes in retail margins rather than prices), prices rose 0.7 percent for the month and 4.6 percent year over year.