Shake Shack Investors Feeling Indigestion Sales soar in the burger chain's first quarter as a publicly traded company but shares take a hit.

Shake Shack's fourth quarter revenue rose 51%, reflecting strong growth for the New York burger chain's first quarter as a publicly traded company. It also outlined sales targets for the new year that met expectations. Here are some of the key details from the company's earnings report.

What you need to know: Shake Shack's results were broadly stronger than Wall Street expected, although this wasn't a home run debut. Total revenue grew to $34.8 million, better than the $33 million projected by Wall Street analysts. Same-store sales jumped 7.2%, better than the 4% predicted by analysts. Still, shares of the high-flying stock were down about 6% in after-hours trading Wednesday.

"We are witnessing a seismic shift in people's understanding and expectations of food and, for the last decade, Shake Shack has helped lead the change in consumer behavior through our fine casual approach," said Shake Shack CEO Randy Garutti.

He said the successful IPO would help fund the company's expansion plans, with a near-term goal of opening at least 10 new domestic company-operated outlets annually. The long-term goal is to operate at least 450 U.S. company-operated Shakes.

Shares of Shake Shack more than doubled on the first day of trading in late January as investors placed a bet that the small chain could one day become the next Chipotle. Fast-casual restaurants have menus that are filled with food that consumers perceive as healthier fare than what fast-food competitors sell, but without the table service found at restaurant chains. And while many banks that cover the company were optimistic about Shake Shack's future, they warned shares were a tad too pricy based on where the company's business stands today.

The big number: The net loss for the latest quarter totaled $1.4 million, or five cents per share, included four cents in expenses associated with the IPO. Analysts surveyed by Bloomberg had anticipated a three-cent loss, which excludes items like the IPO costs. Shake Shack also projected total revenue of $159 million to $163 million for the current year, compared to the $161 million Wall Street estimate.

What you might have missed: Average weekly sales for domestic company-operated Shake Shack locations was $85,000 for the fourth quarter of 2014, a decline of 3.4% from $88,000 a year earlier. This isn't exactly a surprise, as Shake Shack had warned that average volumes were significantly higher in Manhattan, where the chain started, than in locations outside that high-traffic borough. As a result, as Shake Shack opens more stores, average volume trends are expected to continue to decline.