I think that a better solution is to use the stock market as a fair lottery.

Fair systems are good for the person who would otherwise be exploited. They aren't good for the one who is seeking advantage. The whole point in this branch is that you were considering the availability of finding deals that give you positive expected returns.

If you are looking for a way to ensure a real positive expectation from a deal you don't create a stock market, you create a black market.