Wall street tries be subtle most of the time, but in reality this is what they do everyday. Think about it: the big companies (Morgan Stanley, GS, BofA, Ameritrade) are selling stock to retail customers, and they know for a fact what companies people are selling/buying in volume each day, so they can make trades confident that they will make money. Nobody outside this group has direct information about the sell/buy levels of each stock, so this is a rigged game for them.