No. 1 in Security

LifeLock
11,474.3% Three-Year Growth
Revenue: $131.4 Million
Employees: 482
CEO: Todd Davis
Founded: 2005
Overall RANK: No. 8
Tempe, Ariz. lifelock.com

Since its inception in 2005, LifeLock has guaranteed its customers that it will spend up to $1 million to resolve any instances of identity theft. But the company didn't take off until CEO Todd Davis dreamed up an even bolder advertising message: He gave out his Social Security number to demonstrate just how confident he was in his company's services. The pitch was so zany that one television host wouldn't allow him to mention it during an interview. It also resulted in a Federal Trade Commission complaint, which LifeLock settled with a payment of $12 million. But LifeLock adjusted its service and kept growing. 'The unintended consequences were that it made us even better,' Davis says. Today, LifeLock has more than 1.7 million customers; fewer than 1,500 of them have had to invoke the guarantee.