This is a complicated issue and not very well understood as you can see in some of the replies to this comment. The term HFT is used to describe a lot of strat

This is a complicated issue and not very well understood as you can see in some of the replies to this comment. The term HFT is used to describe a lot of strategies, and many of them are overall good for the market. Elimination of human specialists and market makers and subsequent tightening of spreads is definitely a good thing. Also, arbing prices between different markets is also a good thing and those with the best technology will succeed there. But there are HFT strategies that are bad for the market where the HFT algorithms are enriching themselves while providing no benefit to anyone else and actually causing the market harm. Take a look here for more details on "quote stuffing" and other malicious HFT practices: http://www.nanex.net/aqck2/4022.html http://www.nanex.net/aqck2/4022.html