The flat reading for core prices, which excludes food and energy, was helped by a 1.2 percent fall in the cost of light trucks, a category that includes sport utility vehicles.
For the 12 months ending in December, prices at the wholesale level were up 4.4 percent compared to a 0.9 percent drop in wholesale prices in 2008. That big swing reflected a rise in energy costs in 2009.
Core inflation at the wholesale level was much better behaved last year, rising by 0.9 percent after having surged by 4.5 percent in 2008.
Last Friday, the government reported that consumer prices edged up a slight 0.1 percent in December with core prices up the same amount. That finished off a year in which consumer prices rose by 2.7 percent, reflecting higher energy costs during the year. Excluding food and energy, core consumer prices were up 1.8 percent, matching the rise in 2008.
Many economists are looking for inflation pressures to moderate even more in 2010 as the worst recession since the 1930s keeps exerting downward pressure on prices.
The low inflation has allowed Federal Reserve officials to push a key interest rate to its lowest level on record. The Fed's target for banks' overnight lending rate has been at 0 to 0.25 percent for more than a year now. Many analysts believe the Fed will keep rates low for much of 2010 because of their belief that the economy will not be growing fast enough to keep the unemployment rate from rising.
The jobless rate currently stands at 10 percent and many forecasters believe it will keep climbing and hit 10.5 percent by the middle of this year before starting to decline.