As somebody who used to work in Program Trading, I suspect that unanticipated side effects of Reg NMS amplified already substantial market movements. The regul

As somebody who used to work in Program Trading, I suspect that unanticipated side effects of Reg NMS amplified already substantial market movements. The regulation, designed to prevent trade-through, has the effect of creating a submarket for those interested in fast execution at any cost. This submarket is very light on liquidity.