> Furthermore, if someone is really smart enough to beat the market consistently why on earth would they trade just on their own personal account? Alternativel

> Furthermore, if someone is really smart enough to beat the market consistently why on earth would they trade just on their own personal account? Alternatively, if you have a strategy that empirically works, and a strategy for identifying such strategies, why take on investors to share the risk? You can scale up your own investment and leverage yourself with less regulatory oversight. Why on earth do you think the top quant companies will leave alpha on the table for you to snatch up? It's not so much that they leave alpha on the table, rather that there is so much alpha available, and the capacity constraints and reward profiles are so different for many of them, that individuals can prosper outside of a firm. They just normally don't, because they lack the same training (and because it's very competitive).