SEATTLE — Costco, the nation's largest wholesale club operator, said yesterday its first-quarter profit rose 10 percent amid strong demand for consumer electronics. The company expects to take a second-quarter charge as it fixes improperly priced employee stock options.

For the quarter ending Nov. 26, net income totaled $236.9 million, or 51 cents per share, compared with $215.8 million, or 45 cents per share, a year ago. Revenue increased 9 percent to $14.15 billion from $12.93 billion last year.

Analysts surveyed by Thomson Financial predicted earnings of 50 cents per share on sales of $14.06 billion.

Costco Wholesale Corp. also trimmed the top end of its earnings guidance for the year to $2.60 per share, from a previous top mark of $2.65, with the low end of the range staying at $2.50. Analysts are estimating earnings of $2.59 per share for fiscal 2007.

Chief Financial Officer Richard Galanti also said earnings in the second quarter could be 62 cents to 66 cents per share, short of analysts' forecasts of 67 cents.

Costco shares fell 11 cents to $54 in after-hours trading, after closing up 97 cents, or 1.8 percent, on the Nasdaq Stock Market.

Sales at stores open at least a year, a key industry gauge called same-store sales, rose 4 percent, the company said.

Comparable sales felt a drag from lower gasoline prices, a year after Hurricane Katrina pinched supplies, Galanti said in a conference call with investors. The retailer sells gasoline.

But Costco also made more money on memberships, which increased by $5 in May, and continues to see strong sales in electronics, particularly flat-panel TVs, he said.

Costco also said it expects to take a second-quarter charge of about $70 million, or $45 million after taxes, as it pays employees the difference of increased exercise prices on some stock options granted from 2000 to 2003.

The company had previously acknowledged "imprecisions" with certain grants. Yesterday, Costco said a company probe into option granting practices found that options for the 1,050 workers in question carried an artificially low exercise price, which could expose them to tax liabilities.