From the interview linked in my other comment here, they’re not likely doing anything particularly special. relevant quotes:
> Now we have some of the smartest people around, working in our hedge fund, we have string theorists we recruited from Harvard, and they're doing simple regression.
> the smarter you are the less likely you are to make a stupid mistake. And that's why I think you often need smart people who appear to be doing something technically very easy
> we had 7 Phd's just cleaning data and organizing the databases
> Now we have some of the smartest people around, working in our hedge fund, we have string theorists we recruited from Harvard, and they're doing simple regression.
> the smarter you are the less likely you are to make a stupid mistake. And that's why I think you often need smart people who appear to be doing something technically very easy
> we had 7 Phd's just cleaning data and organizing the databases