Subprime Meltdown

Why are there so many foreclosures? Why would banks, the pillars of fiscal responsibility and risk aversion, lend money to subprime borrowers who couldn't afford to repay their loans? How did Wall Street manage to hide the risk and sell the subprime mortgages? How did the subprime mortgage business unravel and evolve into a worldwide liquidity crisis? What are the frauds and scams, how do they work and what should you look out for? What's the forecast for the future and what conclusions can be drawn?