[fractionalhare]

Medallion is far beyond 15%/year. Between 1988 and 2018 they had an average annualized return of 39.1%. And the variance is remarkably low: since 1990 there has never been a year with less than a 20% return.

These figures are net. And for what it's worth, I am in the industry and I don't know any professional who thinks there's obvious fraud going on. It's possible, but you make it seem like there's a consensus that it's illegitimate when you say "most sane people." Frankly it's the other way around.

People who think the returns are fraudulent tend to be outside the industry and thoroughly unacquainted with what quantiles of returns are rare versus implausible. They usually hand wave a misinterpretation of Buffett's famous bet against hedge funds and Fama's (strong) Efficient Market Hypothesis.