[trickledown]

Geesh, what do you want for free.

[jfengel]

Well, "free". They hold your money and your stocks, which gives them opportunities to make profits. They also play middleman (or rather, sell the rights to be a middleman), making a profit on the difference between the asking and selling prices.

[missedthecue]

Brokers make little of their profit from commissions. Even legacy brokers like Schwab. They make their money on advisory services and margin lending.

[chickenpotpie]

No such thing as free in the world of for-profit companies. They're worth billions of dollars for a reason.