People also might care if most of their retirement rests with some large insitutional investor. So if you invest with an active mutual fund, HFT is either a) d

People also might care if most of their retirement rests with some large insitutional investor. So if you invest with an active mutual fund, HFT is either a) detecting any large move the fund makes and pushes up the price of the asset before the trade completes or b) making you use a more costly service to complete the trade secretively to hide it from HFT detection. Passive funds might trade less but their moves are so widely broadcast you don't really need algorithms to detect them.