Shake Shack shares plunge after earnings

Overall, the numbers were a bit better than expected.

Sales jumped 51.5% to $34.8 million in sales in Q4, which was stronger than the $33.0 million expected by analysts. Growth was helped by new stores and a 7.2% gain jump in "same-shack" sales, which are stores that have been open for at least 24 months.

After costs and expenses, Shake Shack had a net loss of $0.01 per share, which wasn't as bad as the $0.03 net loss per share expected.

"We are pleased with the strength of our fourth quarter results and excited to begin our journey as a public company," CEO Randy Garutti said. "As a result of our successful IPO, we have the financial flexibility to support our robust expansion plans. Near-term, we are targeting at least 10 new domestic company-operated Shacks annually, with the goal of doubling our domestic company-operated store count in three years and tripling our store count in five years. Long-term, we see the potential for at least 450 domestic company-operated Shacks."

Shares, however, are down 7% in after-hours trading. It's currently at $43.80, down from Wednesday's closing price of $46.90.

On January 29, Shake Shack's IPO priced at $21 per share and then exploded to north of $52.50 per share on the first day of trading.

We'll have live updates here »

From 2010 to 2014, the company went from 7 shacks to 63 shacks worldwide.

"During the three fiscal years ended December 25, 2013, we grew from seven Shacks in two states to 40 Shacks across six states, Washington, D.C. and eight other countries, representing a 79% compound annual growth rate," the company's IPO filing noted.

Total revenue has surged from just $19.5 million to $82.5 million, which represents a compound annual growth rate of 62%.