You could make the (weak) argument that HFT has created market inefficiencies due to excess liquidity and furthering information asymmetry. Most exchanges (NYSE

You could make the (weak) argument that HFT has created market inefficiencies due to excess liquidity and furthering information asymmetry. Most exchanges (NYSE, NASDAQ, BATS, etc) have "circuit breakers" to prevent a massive sell-off. As far as "noise in the market", you could make the argument that speculative trading is simply that: noise. In this case it is just an algobot doing the noise trading, rather than some idiot that thinks he's found the next best way to "beat the market".