The Labor Department says wholesale stockpiles rose a seasonally adjusted 0.4 per cent. That follows an increase of 0.8 per cent in the previous month. August's increase was the highest in seven months.
Sales at wholesale businesses rose 0.6 per cent in September, up from 0.4 per cent in August.
Stockpiles of computer equipment and machinery increased. Inventories of consumer items such as groceries, clothing and beer, wine and other alcoholic beverages also rose.
The gains in stockpiles helped boost stronger growth in the July-September quarter. And rising sales among wholesalers shows businesses are unlikely to get caught with too many unsold goods on their shelves.