The Commerce Department said Thursday that business stockpiles rose 0.3 percent in April from March. That followed a 0.1 percent decline in March from February.
Sales slipped 0.1 percent in April following a sharp 1.2 percent drop in March. It marked the first back-to-back sales declines in nearly a year, although the weakness was concentrated in manufacturing.
A separate Commerce report showed retail sales jumped 0.6 percent in May. The gain in a critical measure of consumer spending could prompt businesses to keep stocking their shelves.
More restocking boosts economic growth because it means companies are ordering more factory-made goods. The economy grew at a 2.4 percent annual rate from January through March, a gain boosted by stronger inventory growth.
In April, retailers increased restocking 0.4 percent to lead all categories. Manufacturing and wholesale stockpiles both grew 0.2 percent.
The April drop in sales reflected further weakness at U.S. factories. Manufacturing sales fell 0.7 percent. That offset an increase in sales at wholesale businesses. Sales at retailers in April were flat.
U.S. factories have struggled this year as weak economies abroad have slowed U.S. exports. American businesses have also reduced their pace of investment in areas such as equipment and computer software.