Wholesale costs rose last month on gas prices Wholesale costs rose last month on gas prices JOSH BOAK| AP Economics Writer Jan. 16, 2014 Comments WASHINGTON — U.S. wholesale prices increased in December, pushed up by rising gasoline prices and energy costs. But overall inflation remained mild. The Labor Department says the producer price index, which measures costs before they reach the consumer, rose 0.4 percent last month. That ends three straight months of falling wholesale prices. Gas prices reversed recent declines and increased 2.2 percent last month. Home heating oil costs grew at the fastest pace in 10 months, while diesel fuel prices increased at the biggest clip in almost four years. Over the past 12 months, relatively low energy costs have kept inflation tame. Prices have risen a modest 1.2 percent in that period. Excluding volatile energy and food prices, wholesale costs increased 0.3 percent in December and 1.4 percent year over year.