Usually when people claim that HFT strategies “front-run” they are talking about aggressor/taker strategies that are trying to shave off every nanosecond of lat

Usually when people claim that HFT strategies “front-run” they are talking about aggressor/taker strategies that are trying to shave off every nanosecond of latency to increase the chance of a fill at the best possible price. Because these strategies are actively racing other participants for a fill, some people (inaccurately) call this “front-running”, presumably because they are “running in front” of other participants, but this isn’t what is usually meant by front-running. As another commented has pointed out, front-running (in the sense I described it in my previous comment) is explicitly prohibited by regulation in the US, so to misuse the term in this way is to accuse someone of acting illegally without actually understanding what the terms mean.