[makomk]

The existing retail brokers were also, with very few exceptions, selling trading requests on top of the fees they charged. (Also, in general this actually results in better-than-market prices because the trading firms know that retail traders aren't likely to have information they don't and aren't likely to be making large market-shifting trades, so they can relatively safely make money by market making between people who want to buy and people who want to sell at slightly different times.)