Originally posted by vhehn
"Since the MM is not willing to sell at 27.18, he MUST either post the order to his quote at 27.18, or send the order to some other avenue for execution (an ECN) at 27.18. The fact that NVDA traded down to 27.16 shows the MM did neither, which is a clear violation of the rules. Why he didn't do it is a question for NASD Regulation. The ask price does not have to be 27.18 for execution - the fact that it traded below 27.18 is all you need to know that the MM screwed him"
i think the part you are missing is that the .16 prints may not have been a mm.if that was an isld trade for those few shares the mm may not even have been involved.so i stand by what i said if the broker he was using doesnt hit isld and the only trades under .18 were isld he gets no fill.
another example i have had is this.if there are only a few shares traded at .16 and and there is a bunch of buyers at .16 ahead of him that take up all the supply of stock at under his limit before his order turn comes up he wont get a fill.anybody who traded ipos in the old days experienced this you had to chase them several points at times even tho you bid above the ask.the only way you know none of the above happened is if the ask traded through his bid.if that happened you know he was cheated.