Where can I find information on how much money there is in the market? I keep on hearing things like, investors are pulling money out of the market, there's not a lot of money in the market, market makers are trading against market makers, but where do these stats come from? I want a way to keep track of how much total money is going in and out of the market. Maybe some data on money going in and out of mutual funds or hedge funds would be nice. Thanks!