A hedge fund is a collection of investors that make bets on the future. The "hedge" refers to the fact that the investors often try to diversify their strategies so that the direction of their bets are less correlated, and they can be successful in a variety of future scenarios. Engineering-focused hedge funds have used what might be called "machine learning" for a long time to predict what will happen in the future. Numerai is a hedge fund that crowdsources its investment strategies by allowing anyone to train models against Numerai's data. A model that succeeds in a simulated environment will be adopted by Numerai and used within its real money portfolio.