Hint: Born with an entrepreneurial streak, this finance star got an early start making money off inefficient markets. He became a baseball card dealer at age 10. By 13, he was lugging his wares in a milk crate and setting up shop at card expos. The hobby, he says, was not so different form the trading of illiquid assets he does now. The company he founded, and now runs, is on track to handle $600 million in transactions this year.
