I don't have a source on this but from what I read they returned ~80% in '09. From the research I've done on them, they generally make tons of very small bets

I don't have a source on this but from what I read they returned ~80% in '09. From the research I've done on them, they generally make tons of very small bets on assets they think are mispriced. Generally speaking, when volatility goes dramatically up is when more assets are mispriced thus leading to larger gains for them. However, we've seen historically low volatility so it makes sense that they're not returning as much right now.