Vineer Bhansali doesn’t sleep much nowadays. Nor is he getting in as many of the long-distance runs that he loves. But he’s having the time of his life.

Bhansali is the founder of LongTail Alpha LLC, a hedge fund in Newport Beach, California, and he’s newly obsessed with what was once among the sleepiest corners of finance: Treasury bonds. With volatility exploding in the long-placid market, he’s ordered his fund to shift away from other strategies and boost its focus on Treasuries. LongTail now buys and sells bonds constantly, he says, making four times as many trades as it did a year ago.