Quote from Pabst:
Of course the massive irony is that by canceling trades the exchanges are penalizing the buyers who step in to stabilize the market. Often these busted trades leave buyers naked short and benefit those directly responsible for the dramatic declines. Price changes don't occur in a vacuum. The reasons for the snapbacks is because risk takers stepped in and made purchases, in many cases not knowing whether the sudden breaks were the first reaction to horrific news.
For the exchanges this will be a tough problem to fix. While many participants choose to have stops away from the market residing on exchange servers, there is little incentive to leave a size bid or offer "live" away from the market. Why work a bid for 500 ES ten handles lower when the only way you're going to get filled is if something bizarre happens as the market trades off 50 points! Thus at any given time, i.e. all the time, the aggregate number of stops far exceeds the number of limit orders in the book. Don't let the size you see in your "market depth" deceive you, that is only a sample of what is close to the market and thus somewhat "marketable". Further away from the current bid/offer the number of limit orders severely decreases and the number of stops hugely increases.
The CME's secret plan to counteract the avalanche of stops is noble, BUT, what if a legitimate terror, assassination, resignation, or Fed action justifies a sudden revaluation of futures beyond a previous defined yardstick. There were a few rate cuts in the last few years where being filled 10 pts worse on a stop would have been a great fill!! For lack of a better idea perhaps there should be no new circuit breakers but instead could the exchanges offer some inducement (waive fees) to institutions who leave resting orders scaled away. I don't know but maybe a great way to "pay" these institutions for liquidity would be to not bust their bargain basement trades when they're actually winners.