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 woman. Zimmerman, who survived a 1990s scandal involving Russia, her husband and Harvard University, is so successful at avoiding the limelight that Leda Braga’s $9.5 billion Systematica Investments Ltd. is often cited as the top woman-led firm by assets.

Swensen, who runs Yale University’s $25.6 billion endowment, and Thomas Steyer of Farallon Capital Management originally staked Zimmerman in 1994 with about $50 million. Yale’s investment now is valued at around $1 billion, making it one of the endowment’s most profitable.

“She’s employing this leveraged strategy to exploit pricing differentials in the fixed-income world with an obsessive focus on risk,” Swensen said in an interview.

Bracebridge has had only eight losing months since 2009. The fund’s 2 percent gain last year eclipsed the industry, which was up 0.6 percent on average, according to data compiled by Bloomberg. Hedge funds had trouble navigating unexpected market events, including a devaluation in the Chinese currency in August, a rally in European government bonds and a steep drop in oil prices.

Ackman’s Pershing Square Holdings, the publicly traded part of his activist hedge fund, lost 20.5 percent last year, hurt in part by a drop in the shares of drugmaker Valeant Pharmaceuticals International Inc. Einhorn’s Greenlight Capital suffered the second losing year in its history, with its main fund falling 20.4 percent due to wrong-way stock picks.

“There were a lot of gopher holes that you could step in,” said Gabriel Sunshine, Zimmerman’s partner at Bracebridge. “We managed to miss most of them.’’

Heavyweight Network

Zimmerman, 52, has a powerful network of allies, including former New Jersey Governor Jon Corzine, who was Zimmerman’s boss at Goldman Sachs Group Inc., where he was co-chief executive officer. Among her top investors is Princeton University’s endowment, run by Swensen protege Andrew Golden.

Corzine said he remembers Zimmerman as a brilliant trader who attracted the brightest of co-workers.