One thing most people don't think about. The kelly criterion isn't particularly useful for investors, as you need to be able to quantify the expected outcomes.

One thing most people don't think about. The kelly criterion isn't particularly useful for investors, as you need to be able to quantify the expected outcomes. It's not particularly useful for gamblers (rarely do they have quantifiable positive expected value), but it's an absolutely amazing resource for casinos themselves. Almost every bet that happens on a casino floor the casino can quantify their expected returns and risks and knowing the state of their bankroll knowing what is sensible to risk or not. But other than that, it probably is mainly useful to teach investors a healthy fear of variance. If it'd be foolish for a casino with a $1M bankroll to let a roulette player bet more than $12000 on a spin, it might give you a healthy sense of the importance of diversification.