Medallion is for employees of Renaissance. It doesn't have customers/partners. If you accept that Renaissance is good at what it does, it's simple to posit that Renaiisance reserves its most profitable activities for its own employees as preferred customers/partners, as a compensation vehicle and a PR/recruiting tactic to make Renaissance look more impressive. Medallion is like Google's "X", in that sense.
This explanation shows why Medallion's high returns are possible, and also why Medallion not actually better than Renaissance's overall average performance (that is, could not be replicated as an indepdent spin of without the rest of Renaissance to extract value from), beyond an acconting illusion to make ordinary wages look like investing.
It's not at all surprising that this could be how Medallian works, since that's just an application hedging, which is Renaissance's core business.
as @jkaptur said, with "partners" I meant their trading partners, clients, service providers. The OP suggested that maybe Medallion has an advantage and kept it. I suggested that a new hedge fund would pay the Medallion partners more and accept less in profit than Medallion.
This explanation shows why Medallion's high returns are possible, and also why Medallion not actually better than Renaissance's overall average performance (that is, could not be replicated as an indepdent spin of without the rest of Renaissance to extract value from), beyond an acconting illusion to make ordinary wages look like investing.
It's not at all surprising that this could be how Medallian works, since that's just an application hedging, which is Renaissance's core business.