Business inventories increased 0.3% in June, the smallest gain since May 2010, the Commerce Department said Friday.
The increase followed a revised 0.9% climb in May that was smaller than originally reported.
Inventories were projected to increase 0.5%, Bloomberg reported.
Sales rose 0.4% after a 0.1% decline the previous month.
Factory inventories, which make up about two-fifths of the total, rose 0.2%, while wholesale inventories, which make up about 30%, gained 0.6%.
When sales are growing, it usually means trucking is seeing additional demand to deliver goods and restock shelves.