Is Top U.S. IPO Performer Since 2009

Over the last two years, the online restaurant reservations site OpenTable has outperformed all other IPOs. I sure wouldn't have guessed that. Chalk that up to a soft market for IPOs and a business that's shown impressive revenue growth. OpenTable gets paid by restaurants when you book through their service.

In the early days after its debut in May 29, the company traded at about 28 dollars a share. It closed Thursday over $65. But now the short-sellers are circling the company, according to a report in Bloomberg. They're betting that the company can't continue to grow while keeping up its profit margins.

The good news for you: more and more restaurants are signing up to work with OpenTable, making it easier to book a date online. At last count, 15,246 restaurants used the company's system.