NEW YORK – Wal-Mart Stores Inc. offered a weak business outlook Thursday as new economic challenges for its low-income shoppers start to take a toll.

The world's largest retailer reported an 8.6 percent increase in profit for the fourth quarter which includes the crucial holiday season. But higher gasoline prices, late tax refunds and the payroll tax increase have it wary about the coming year.

Wal-Mart, based in Bentonville, Ark., is considered an economic bellwether because the retailer accounts for nearly 10 percent of nonautomotive retail spending in the U.S. Low- and lower-middle-income people have continued to struggle even as the housing and stock markets improve.