Quote from gkishot:
Transaction tax is totally not the same as doubling or tripling of commission. This is more equivalent to increasing buy/sell spread, where loss on transaction is percent of position amount.
maybe not. if fills today are worser due to HFT frontrunning, bid/ask spread might widen but in reality go smaller. Yes you will literally see it widen, but these spreads can effectual be smaller without HFT frontrunning. this is my hypothesis. HFT disappear, and investor won't notice much difference at all because they stop losing money to frontrunning order flow HFT. That said, daytraders will die.