WASHINGTON (AP) - U.S. companies continued to build up their stockpiles in November as their sales improved, a sign that businesses believe consumers will increase spending in the months ahead. The Commerce Department says business stockpiles grew 0.4 percent in November. That follows a strong 0.8 percent gain in October. Sales increased 0.8 percent in November after a 0.5 percent gain the previous month. Rising stockpiles should help keep growth solid in the October-December quarter. Several economists project growth at a 3 percent annual rate in that period after a 4.1 percent rate in the previous quarter. Greater restocking boosts growth because it requires more factory production. Retailers led much of the gains in inventories ahead of the holiday shopping season. Wholesalers also increased their stockpiles. Stockpiling by manufacturers was flat.