I run an HFT group, and what he describes isn't what we'd call "retail". He was doing a number of things that professional shops do, including making markets t

I run an HFT group, and what he describes isn't what we'd call "retail". He was doing a number of things that professional shops do, including making markets to avoid paying the spread and paying attention to queue position to predict execution With a bit of luck and a good partner, this guy could have built a sustainable business.