“HFTs appear to assist in decreasing excessive price volatility,” [Professor Alex Frino, CEO of Capital Markets Co-operative Research Centre (CMCRC) and Professor of Finance at the University of Sydney Business School] said. “This is partly due to the way HFT algorithms identify trading opportunities – they’re built to recognise when prices are abnormally high or low, and respond in a way that naturally pushes prices back towards the middle.”
via Securities Technology Monitor: Dark Trading Bad, HFT Good.