Maybe I am reading this wrong. Is he not saying that loosely/unregulated HFT pools would be the cause of the flash crash times ten? So, if HFT is in fact reigned in, the markets should theoretically stabilize as it is unwound. Likely less volatility and lower trading volume. From what I understand, the margins on HFT are slim which is why it is all about speed and high volume. If they are exiting this, then they likely aren't making (enough) money on it and/or they are fearful of a stricter regulatory environment which could lead to even lower profits or penalties. I don't see the end of HFT causing a massive crash. All that money isn't simply going to be pulled out of the market, it will be put back in through the more traditional channels, imo.
