Costco Wholesale Corp. (COST) reported higher-than-expected quarterly profit and a healthy rise in September sales on Thursday, sending its shares up 2 percent in pre-market trading.

Costco (search), the largest U.S. warehouse club operator, said net profit grew to $296.8 million, or 62 cents a share, in the fiscal fourth quarter ended Aug. 29, from $239.4 million, or 51 cents a share, a year earlier.

The earnings beat analysts' average forecast of 58 cents a share as compiled by Reuters Estimates.

Equity analyst Dan Geiman of McAdams Wright Ragen said the company held down costs and improved operating margins in the quarter.

"Overall, it appears to be a fairly upbeat report and I would expect some upward revisions in terms of expectations," Geiman said.

Costco shares rose to $43.75 in pre-market trade on the Inet electronic brokerage system, up from a close at $42.93 on Wednesday on the New York Stock Exchange.

Net sales rose 11 percent in the fourth quarter to $14.83 billion. Comparable warehouse sales during the period gained by 8 percent.

Costco, based in Issaquah, Wash., said that during September, net sales rose 11 percent to $4.53 billion.

This contrasted with a disappointing August when sales rose just 4 percent due to sluggish back-to-school trade. Growth of 7.5 percent had been expected.

Costco operates 442 warehouse stores in the United States and Puerto Rico, Canada, Mexico, Britain, South Korea, Japan and Taiwan.