Who Is Billy Walters?

Last year, there were headlines about a federal insider-trading investigation of two well-known figures: pro-golfer Phil Mickelson and billionaire investor Carl Icahn. But also on the target list was William T. "Billy" Walters. ESPN investigative reporter Mike Fish wondered who that was.

The world's most successful sports bettor runs a sophisticated gambling syndicate with handicappers, computer engineers, and secret employees who pose as high rollers using his money.