In a year when titans Bill Ackman and David Einhorn each lost more than 20 percent for their investors, David Swensen’s bet on a little-known hedge fund kept making him money. Nancy Zimmerman’s Bracebridge Capital has gone from $5.8 billion in assets four years ago to $10.3 billion today with a return of about 10 percent a year since its inception. That makes it the largest hedge fund in the world run by a...