New York ? Back-to-school sales failed to give the nation’s largest merchants a much-needed lift as consumers fretted about job security and stock market volatility.

Retailers’ reports on August sales Thursday showed that while consumers have been spending on homes and cars, they have pinched pennies at department stores and mall-based clothing retailers.

Even Wal-Mart Stores Inc., Target Corp. and Kohl’s Corp., which are considered largely recession-proof, posted results below Wall Street expectations.

“Consumers are shopping only on need, and they are being rewarded by waiting,” said Richard Jaffe, an analyst at UBS Warburg Securities. “Economic uncertainties have caused people to think twice about spending.”

Jaffe added that cool weather earlier in August hurt apparel sales.

“They’re buying cars, but they are staying clear away from department stores and general merchandise stores,” said Michael Niemira, vice president of Bank of Tokyo-Mitsubishi Ltd.,

Department stores’ same-store sales fell 4.8 percent in August, the worst monthly performance since the 6.8 percent decline recorded in September 2001, Niemira said.

Industry observers offered mixed forecasts on consumer spending for the rest of the year.

“There is no reason that the consumer mindset will change. Holiday will keep pace with a mediocre performance,” said Tad Shepperd, president of ShopperTrak RCT, which tracks sales of 15,000 individual stores.

Carl Steidtmann, chief economist at Deloitte Research, predicted that continued mortgage refinancing will free consumer dollars and increase overall spending by 6.5 percent in the second half of the year.