WASHINGTON – Inventories held by wholesalers rose for a third consecutive month in March and sales increased by more than double the expected amount. Rising demand is making businesses more confident about the future, a key development needed to sustain the recovery.

Wholesale inventories rose 0.4 percent in March, slightly lower than the 0.5 percent gain that had been expected, the Commerce Department said Tuesday. Sales shot up by 2.4 percent, more than double the 1.1 percent increase economists had forecast.

It marked the 12th straight month that sales have risen at the wholesale level, an encouraging sign for the economic rebound. The hope is that businesses will step up ordering and restock depleted shelves, giving a boost to factories and prompting them to rehire laid-off workers.

Mike England, an economist with Action Economics, said the big sales gain among wholesalers reinforced earlier reports of March sales increases at the retail and manufacturing levels. Those gains are out-performing market assumptions and bolstering the outlook for the overall economy in the months ahead, he said.

Inventories have risen for five of the past six months. A 0.5 percent increase in October was the first gain after 13 consecutive declines. Before October, businesses had gone through a massive liquidation of their stocks as they struggled to contain costs during the recession.