Robin hood is free because their flow goes to third parties like citadel instead of smart order routers at sell side firms. But that is an edge of a less than a

Robin hood is free because their flow goes to third parties like citadel instead of smart order routers at sell side firms. But that is an edge of a less than a second. It is generally good to be able to ascribe an identity to order flow, but retail tends to behave in a predictable way at medium time scales