Robert Steven Kaplan may be the equivalent of a fill-in head coach who takes his team to the Super Bowl and wins.

While other funds struggle through the mortgage crisis, a hedge fund founded by former Harvard Management Co. CEO Jack R. Meyer is flourishing.

Meyer and former Harvard colleagues run Convexity Capital Management, which makes trading bets that benefit from volatility. The fund, started last year, had disappointing early results. But recent market swings have brought a turnaround.