With the rules saying that markets cannot cross or trade through the spread, it seems to me this slows down any market to match the slowest mover...in this case the AMEX floor. If ISLD doesn't display *and* rejects orders that would trade thorugh the "national" spread, then it also seems to me that ISLD can no longer lead the AMEX QQQ quote feed like it did up to today. There would seem to be other effects we can expect. For instance ISLD can no longer instantly match because even if it has a match it needs to check first to make sure it does not trade through the spread ("hey sleepy-head, is it okay for me to fill these orders?"). At worst you do not get a fill at all (rejected), or even if you do get a fill I wonder if this extra step multiplied by the number of attempted trades would slow them down noticeably.Originally posted by chasinfla
Electronic traders are threatening to eat their lunch and so they are changing the rules.
I used to regard the ISLD book (and NQ) as being closer to reality than the QQQ chart which consistently lags and is filled with prints that come in at varying degrees of lateness. Those days seem to be over. I guess it's going to be time to watch and perhaps send a few experimental 100 share trades via different routes to see how things are forming up.
And I really wish someone would publish SEC's fax number so that we can all send in our ISLD testimonials...
--Derek
