A slew of retailers issued lackluster same-store sales data for August.

Wal-Mart

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, the world's biggest company, said sales at stores open at least a year came in below expectations, citing unusually warm weather. The Bentonville, Ark.-based company posted a 3.8% gain in August same-store sales, below its forecast for 4% to 6% growth. Same-store sales at its Wal-Mart division climbed 4.3%, while its Sam's Club unit posted a modest 1.1% gain.

Federated Department Stores

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, which operates Macy's and Bloomingdale's, said same-store sales fell 5.8% in the four weeks ended Aug. 31. Total sales for the month dropped 3.8% to $1.09 billion from $1.3 billion last year. "We obviously were disappointed with our August sales performance," the company said. "However, we did see some improvement in sales trends during the last two weeks of the month, including the Labor Day weekend, which gives us encouragement for achieving our plan of a 1% to 3% same-store sales increase for the fall season."

Consumer electronics chain

Best Buy

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said its second-quarter comparable-store sales for its rose 2% as overall weakness in the economy contributed to sluggish demand for its home entertainment products. In August the company lowered its outlook for the second time in two months, saying it would not meet its target of 4% to 5% sales growth. But on the upside, Best Buy said total sales for the second quarter jumped 20% to $5 billion due to the addition of 76 new store locations.