Business inventories rose 1% in May, the Commerce Department said Thursday.
The increase followed another 1% climb in April that was more than originally reported.
Sales decreased 0.1%, the first decline in nearly a year.
Inventories were projected to increase 0.9%, Bloomberg reported.
Factory inventories, which make up about two-fifths of the total, rose 0.8%, while wholesale inventories, which make up about 30%, gained 1.8%.
When sales are growing, it usually means trucking is seeing additional demand to deliver goods and restock shelves.