Hedge fund titan Peter Brown has slept in his office 2,000 times—and offered an employee a pay rise for answering the phone in the middle of the night

Peter Brown, chief executive officer of Renaissance Technologies LLC, speaks during a Senate Permanent Subcommittee on Investigations hearing in Washington, D.C., U.S., on Tuesday, July 22, 2014. (Credit: Andrew Harrer—Bloomberg/Getty Images)

If your boss called you in the small hours of the morning with a pressing work question, you might be understandably frustrated.

But if they called and offered you a pay rise, you might nod off again with a smile on your face.