The rule does not prevent you to initiate the 4th position. Not too many brokers prevent you to initiate the 4th position even after making 3 day-trades in 5 days. For example, Ameritrade lets you have the 4th position as the rule permits. They will still count the number of day-trades and generate warnings for the users about the possible consequences. They leave it up to the informed users what s/he wants to do with the 4th position. However, IB does prevent you to initiate the 4th position--regardless of your intent on when you might want to close the position--if you have already done 3 round-trip trades in rolling 5 days. It is more like a broker specific problem. It is IB's shortcomings from any knowledgeable user's point of view. On the other hand, the broker (e.g., IB, etc.) would potentially generate more commissions by restricting someone to initiate the 4th trade for only 1-5 days than restricting someone for 90 days. Therefore, with IB if you want to be able to initiate a position in an non-PDT account, you need to make no more than 2 day-trades in 5 business days. It is like practically having further restrictions. To make things worse, at IB, you can still end up having 4 round-trip trades in different ways--sometimes without being informed, and then have your account restricted for 90 days any way.
The rule is incoherent and totally unjust. It has no merit whatsoever for the customer/trader or for the Industry members. And in practice its "enforcement" is totally distorted since no broker is applying the 6% test before applying the 3/5 rule, and what retail member wants a customer locked up for 90 f-king days so that they cannot generate more commissions, and even some liquidity. Would some aware institutional member please tell us WHY the heck they don't want to oppose the PDT rule at the member level!? Isn't it time to forget about protocol or diplomacy, and ask the NASD to rescind it NOW since the markets have improved from the early days of the 21st, and the traders left in the markets can fend for themselves. It's a pain in the arse for all concerned. I can't get funds from my grandma or uncle or cousin or friend unless they are willing to fork over 25000 for a speculative account to be actively traded. The PDT rule is like Y2K - total feak over nothing! Imagine if the NASD/SEC were involved in the Y2K conspiracy---who the H knows what insanity they might have enacted! LMAO