U.S businesses left their stockpiles unchanged in October, while total business sales fell for the second month out of the past three. The results could raise concerns about economic growth this quarter.

The Commerce Department says October business inventories were flat following a tiny 0.1 percent rise in September. It was the weakest showing since July. Sales fell 0.2 percent in October after being flat in September.

Overall economic activity was restrained over the summer partly because businesses worked to align their stockpiles with weaker sales. Economic growth slowed to an annual rate of 2.1 percent in the third quarter.

Many economists believe continued weakness in inventories will dampen growth this quarter as well.