Who controls pre market trading in Nasdaq ? The pre market trading in Nasdaq is the source of some very unusual price behaviour . Who is the dominant player ? Days like today with 400 point rises occur on a backdrop of packed signals . Almost like quote stuffing but with bids to keep market in perpetual uptick all day . Complete artificiality . Same dynamic with volatility . Vol suppression seemed characterized by quote stuffing but offer side to keep vol moving down and fully suppressed