The ultrarich DS uses AI for microsecond strip offs
of profit. Ameritrade SELLS like the others knowledge
of your upcoming trade (ie before it proceeds) to the
DS to take advantage of YOUR biz.
Also they probably make more money with the puts gets etc.
which are multipliers of the relative tiny money they
use to push the stock price up and down.
And there are those counterfeit shares allowed by “law”
for them only. Counterfeiting helped China take over the
America by paying fake=”billions to each power in Congress”
in addition to their fake=”ballots”.
Counterfeiting should have been ILLEGAL for them, too;
BEFORE America tanked due to stolen election.
Indeed. They get the trade data before it executes, and they get an opportunity to take the other side of that trade - or, if they are making a market, they can move their bids/asks according to the data they receive.
Then of course, there are the rebates that the exchanges pay for liquidity order flow. So you can buy a stock for $1 and sell it seconds later for $1 and make a profit just from the rebate.