True -- agreed that a pure front-run that provides no liquidity would appear to have negligible value aside from generating heat. In devil's advocate-mode: The

True -- agreed that a pure front-run that provides no liquidity would appear to have negligible value aside from generating heat. In devil's advocate-mode: The HFT trader is still providing liquidity for that person on the way. If someone else were to purchase the shares ahead of the inbound trade, the inbound buyer might not be able to acquire those shares. If the inbound trade were a limit order, rather than a market order, then the HFT trader might not have room to profit.