You and patio11 are smart enough to understand that all the HFT strategies are equivalent to front running.  Each and every HFT strategy exploits some aspect of front running. In this world the market is by definition a misnomer because it does not exist on a single exchange and is fragmented.<p>Sure you cannot front run a single exchange when every buy and sell is on that single exchange but that&#x27;s not how the actual market and front running works.<p>HFT requires that the market is distributed. You can say this is market maker arbitrage but it is actually equivalent to front running the market the same way a retail to broker initiated trade can be front run.