Economist Paul Krugman explains the ongoing financial crisis in 4 small bullet points in his Op-ed in The New York Times. . This is the msot succint explanation I have come across. Follow the link and read the full article if you have time. It is one of the better ones by Krugman.
The 4-Steps:
1. The bursting of the housing bubble has led to a surge in defaults and foreclosures, which in turn has led to a plunge in the prices of mortgage-backed securities — assets whose value ultimately comes from mortgage payments.
2. These financial losses have left many financial institutions with too little capital — too few assets compared with their debt. This problem is especially severe because everyone took on so much debt during the bubble years.
3. Because financial institutions have too little capital relative to their debt, they haven’t been able or willing to provide the credit the economy needs.
4. Financial institutions have been trying to pay down their debt by selling assets, including those mortgage-backed securities, but this drives asset prices down and makes their financial position even worse. This vicious circle is what some call the “paradox of deleveraging.”