That makes a lot of sense. And also explains why the the other funds aren't as 'stellar'. I mean all these quants are in the same company, how is one fund perfect, and the others lackluster.
Simons, for example, has a ~$21B fortune, and I doubt he gets more than 1/3rd of Medallion's $10B capacity. He's probably got more money in RIEF than in Medallion.