Business inventories rose 0.4 percent in December, reinforcing the view that fourth-quarter economic growth received a big boost from companies restocking their shelves.
The Commerce Department said on Tuesday that inventories climbed to $1.56 trillion in December.
Economists polled by Reuters had forecast inventories increasing 0.5 percent in December. Sales rose 0.3 percent in November, the government said.
Inventories are a key element for measuring changes in gross domestic product.
A report on January 27 showed growth in business inventories helped drive a 2.8 percent expansion in gross domestic product during the fourth quarter.
Tuesday's report showed manufacturing stocks rose 0.1 percent in December, while retailers gained 0.2 percent and wholesalers' stocks edged 1.0 percent higher.
Business sales advanced 0.7 percent to $1.23 trillion.
The inventory-to-sales ratio, which measures how long it would take to clear shelves at the current sales pace, fell to 1.26 months from 1.27 months in November. (Reporting by Jason Lange; Editing by Andrea Ricci)