Propublica has a great story on the creation and functioning of artificial markets in Wall Street. These markets are basically based on the idea of creating the illusion of a market, and profit from it. The game is also known as a Ponzi scheme.
“Over the last two years of the housing bubble, Wall Street bankers perpetrated one of the greatest episodes of self-dealing in financial history. Faced with increasing difficulty in selling the mortgage-backed securities that had been among their most lucrative products, the banks hit on a solution that preserved their quarterly earnings and huge bonuses:
They created fake demand.
A ProPublica analysis shows for the first time the extent to which banks — primarily Merrill Lynch, but also Citigroup, UBS and others — bought their own products and cranked up an assembly line that otherwise should have flagged.”