> I think that fees a) keep out the "riffraff" and b) brokerages know that it's a zero-sum game to compete on them. There are also costs per position per inves

> I think that fees a) keep out the "riffraff" and b) brokerages know that it's a zero-sum game to compete on them. There are also costs per position per investor. Some services that brokerages have are based on position counts. An investor with 10 shares in 1 stock is cheaper to maintain than an investor with 1 share in 10 stocks. (One example is prospectuses. If you buy a fund, you're entitled to the prospectus to be delivered within a certain amount of time post trade. If you just by 1, 2, 3, then 4 shares of the same fund, you only get one file/document delivered to you.)