Costco Wholesale ( COST) shares were up in premarket trading after the warehouse retailer beat analysts' expectations by a penny in the second quarter.

Net income rose 25% to $226.8 million, or 48 cents a share, from $182.1 million, or 39 cents a share, a year ago. The consensus forecast was for 47 cents a share, according to Thomson One Analytics.

Revenue in the quarter ended Feb. 15 increased 14% to $11.33 billion.

The second-quarter operating results included an after-tax charge of $16 million, or 3 cents a share, covering an increase in workers' compensation loss reserves.

The warehouse shopping club also said net sales hit $3.49 billion in February, up 14% from a year ago. Same-store sales in the U.S. during the period rose 9%, while international sales jumped 21%.

Costco said results were helped by the weak dollar and the California grocers union strike.

Costco shares were up 24 cents to $39.95 before the open.