There's a subtlety here: Renaissance is a company which manages hedge funds. They're famous because their main fund, Medallion, has done exceptionally well.

There's a subtlety here: Renaissance is a company which manages hedge funds. They're famous because their main fund, Medallion, has done exceptionally well. The only investors in Medallion are Renaissance employees; it's capacity is limited, so that even employees can't generally invest as much as they'd like. Renaissance also manages several other hedge funds, which have much higher capacity, and have both employee and outside investors.