PLEASANTON (AP) — Discount clothing retailer Ross Stores Inc. said Thursday that a key revenue indicator climbed 6 percent in December and raised its fiscal fourth-quarter earnings guidance, sending the company's shares higher.

The rise in revenue at stores open at least a year was about double what the company and Wall Street expected. The company expected growth of 2 to 3 percent, and Thomson Reuters says analysts it surveyed were projecting an increase of 2.7 percent on average.

Revenue at stores open at least a year is considered an important measure of retail health because it leaves out results from stores that have opened or closed within the last 12 months.

The company said its total revenue grew 11 percent to $1.28 billion over the five weeks ended Dec. 29.

Ross runs about 1,100 Ross Dress for Less stores around the country.

Based on its December results it now expects net income of $1.05 to $1.06 per share for the fiscal fourth quarter, which ends in early February. Previously the company expected income of 99 cents to $1.04 per share.

On average analysts expected the company to earn $1.04 per share over the three months ending Feb. 2.

Ross said sales at stores open at least a year should grow 1 to 2 percent in January.

Shares of the Pleasanton, Calif., company rose $4.13, or 7.6 percent, to $58.57 in late morning trading. Its shares traded as high as $70.82 in mid-August and as low as $47.75 almost a year ago