Wal-Mart (WMT) says August sales increased 3% beating the company’s forecast of a 1% to 2% rise for stores open at least a year.The nation’s largest retailer cut prices on groceries consumer electronics and back-to-school supplies. Wal-Mart says September same-store sales may rise 2% to 3%. Overall sales at Wal-Mart stores rose 2.8% in August while sales at Sam’s Club a warehouse chain rose 4.2% - or 7.5% including sales of fuel.“The underlying business performance for Wal-Mart US continued to show strength and the improved relative performance has resulted in market share gains ” Eduardo Castro-Wright head of the ...