I was recently thinking about the recent popularity and success of the CME, especially the tremendous growth in volume in the Eminis over the last few years. My theory on this is as follows: The PDT rule made it difficult for the average inexperienced trader (read: sucker) to get into the popular and easily accessible stock market (think of someone who has <25k and wants to be a day trader). This person now wants to make (lose) a certain amount per day and soon realizes that the equity markets will not give him the "flexibility" he needs to overtrade. Hence, after visiting sites like ET, he gets familiar with the eminis and starts trading them. The word soon spreads that there is an easily accessible (in that start-up capital sense) market and hence a flood of undercapitalized and inexperienced traders flood the eminis exchange. Hence the explosion in the CME volumes. Now, by initiating the PDT rule, what has the NASD actually done to the stock exchanges? They've severely limited their potential business! The stock exchanges can no longer attract the same volume of participants due to the initial margin requirements. The NASD is killing the potential business of the all the MM's, ECNs, brokers etc, etc... I would think the industry as a whole would soon start attacking the NASD after seeing the explosion in business at the CME... Any thoughts?