Warehouse club operator Costco Wholesale Corp (COST.O) reported better-than-expected quarterly comparable-store sales on Thursday, helped by higher membership fees and strong sales in the United States.

Sales at established stores open for at least a year rose five per cent, excluding the impact of changes in gasoline prices and foreign exchange.

Analysts on average were expecting growth of 3.7 per cent, according to research firm Consensus Metrix.

Net income attributable to Costco rose to US$700 million, or US$1.59 per share, in the third quarter ended May 7 from US$545 million, or US$1.24 per share, a year earlier.

Total sales rose eight per cent to US$28.86 billion.