Ex-Wall Street guy here. High speed trading has no societal value and relies on a large number of bad-faith bids and offers - these people are parasites. Crea

Ex-Wall Street guy here. High speed trading has no societal value and relies on a large number of bad-faith bids and offers - these people are parasites. Creating liquidity has some value - though not as much as bankers tell themselves. But HFT does not add liquidity. No one needs subsecond liquidity, but even more important, HFT traders vanish like a fart in a windstorm the moment liquidity is actually challenged. Market makers are the ones who provide consistent liquidity, because they have to keep inventory of the stocks. Now look at what HFT does - they flood the wires with hugely out-of-the-money bids and asks, all of which are in bad faith, because they know they won't even get hit or lifted. So everyone else pays for this, and they get to shake absolutely everyone down for a few pennies, a trillion times a year. --- It would be trivial to stop them without changing the markets in the least. Even just charging a dollar for every "bad faith" bid or offer made that expires without being within, say, 10% of the actual price, would put a big dent in them. Punitive taxes on trades where the trader doesn't keep the position for more than a few seconds would also be very effective.