Inventories at retailers, manufacturers and wholesalers rose 0.4 percent in March, the Commerce Department (news - web sites) said, after an increase of 0.7 percent the previous month.
The gain beat Wall Street expectations for a 0.2 percent rise and partly reflected cars sitting on dealer lots.
Stocks at retailers rose 0.8 percent, while inventories at manufacturers were unchanged. Supplies of motor vehicles and parts climbed 1.3 percent.
Business sales surged 1.8 percent, the largest jump since April 2002, helped by good business at retailers.
Sales at retailers surged 2.4 percent after falling the previous month and manufacturing sales rose 1.9 percent.
The stocks-to-sales ratio -- the amount of time it would take to deplete inventories at the current sales pace -- fell to 1.38 months from 1.40 months in February.