This film won the Oscar for Best Documentary for 2010 and once you view it, you will agree.
Matt Damon narrates on what caused the collapse of Wall Street back in 2008. Greedy banks pushed for deregulation which allowed them to gamble more money on the market than what they could afford. They increased the risks by accepting mortgages from homeowners who could ill afford paying the monthly mortgages just so they could make profits on the commissions on the processed loans. They then sold these bad loans to investment firms (retirement funds, pensions and unions) and insured them with AIG because they knew the loans were bad, making even more profits.
The whole scheme collapsed when the investment firms got wise to the banks crooked deals and no one could sell the bad loans to anyone so everyone took trillions in severe losses (wiping out pensions, retirement funds and investment firms, devaluing the overall housing market) and ended up with the government bailing them all out on our dime.
The ominous end shows that while President Obama wanted to reregulate the banks, the current majority in the Senate and House (who are sponsored by the banks) rejected the laws. Meanwhile, banks are pushing even for more deregulation to further their profits.
If at the end of this movie you are not disgusted and enraged on what caused our economy to tank and to cause our government to go into severe debt, you only have yourself to blame when this happens again...