Quote from Lawrence Chan:
There are many kinds of bots.
Your assumption on the arb bots is correct but they are a very tiny bunch in the stock mkt nowadays.
Market making bots works like the size players you are thinking of and they dominate the tape in normal mkt environemnt.
Difficult to explain until you have worked on the other side of the fence.
Alright thanks for your observation. Btw, Lawrence, just as a curiosity where did you work (not asking for name, but just whether it was a bank/MM operation/hf and in what role - algo trader/quant developer etc.) before you started your own firm. Thanks.