FWIW: I called ameritrade the other day because they told me that I couldn't trade pre-market and the very next day volume was at 50,000 by 8:45am. After alot of confusion he finally called his "trading desk" and they said that the mm's they use don't trade pre/post market but that there, obviously, were some that did. He actually called them the "boiler room" mms.
Thats what I understand..but ive seen it trade 320,000 shares before the market opened and when the bell rings they are wiped out to 0. Is this the MM's catching up maybe?
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