Shake Shack Restaurant Sales Jump in Third Quarter

Shake Shack Inc, known for its antibiotic-free hamburgers and indulgent sides, on Thursday said sales at established restaurants jumped more than expected in the third quarter, sending its shares up 7 percent in extended trade.

The New York-based chain, founded by celebrity restaurateur Danny Meyer, said same-restaurant sales were up 17.1 percent, easily topping analysts' average call for a rise of 10.6 percent, according to research firm Consensus Metrix.

Those sales include the results from just 16 domestic company-operated units open for 24 months or longer. The company has 41 company-operated U.S. shops.

Critics worry that the chain's explosive same-store sales growth, a gauge of restaurant performance, will fade as it expands beyond very dense urban areas.

Shake Shack's net income roughly tripled to $1.5 million, or 10 cents per share.

The company, which has 75 restaurants around the world, raised 2015 forecasts and set its 2016 outlook.

The chain boosted its 2015 revenue forecast to a range of$189 million to $190 million from $171 million to $174 million previously. Its new same-restaurant sales forecast calls for growth of 11 percent to 12 percent. It previously said it expected "same-Shack sales" growth in the mid- to high-single digit percentages.

For 2016, Shake Shack forecast total revenue of $237 million to $242 million and same-restaurant sales growth of 2.5 percent to 3 percent.

Shares of the company, which went public on Jan. 30 with an IPO offering price of $21, flirted with $100 before early investors were given the chance to cash out.

On Thursday, the stock was up $3.46 to $54.57 in after-hours trading.

(Reporting by Lisa Baertlein in Los Angeles; Editing by Meredith Mazzilli, Bernard Orr)