As a counter-argument, from [0]:

> The Medallion Fund, which has been available exclusively to current and past employees and their families, surged 80% in 2008 despite hefty fees; the Renaissance Institutional Equities Fund (RIEF), owned by outsiders, lost money in both 2008 and 2009; RIEF declined 16% in 2008

A cynic in me would say that Simons used a better strategy for the Medallion Fund than for the RIEF.

[0] https://en.wikipedia.org/wiki/Jim_Simons#Controversies

The Medallion Fund does use a better strategy than REIF. It only worked up to a certain scale where they started moving the market though, which is why they ended up kicking out outsiders.

REIF just lets them use Medallion as marketing while getting those sweet AUM fees on a massive fund.