An interesting article by Adam Davidson at Reuters:
How AIG fell apart
When you hear that the collapse of AIG or Lehman Bros. or Bear Stearns might lead to a systemic collapse of the global financial system, the feared culprit is, largely, that once-obscure (OK, still obscure) instrument known as a credit default swap.
So, what is a CDS, and why is it so dangerous?
At first glance, a credit default swap seems like a perfectly sensible financial tool. It is, basically, insurance on bonds. Imagine a large bank buys some bonds issued by General Electric. The bank expects to receive a steady stream of payments from GE over the years. That's how bonds work: The issuer pays the bondholder some money every six months. But the bank figures there's a chance that GE might go bankrupt. It's a small chance, but not zero, and if it happens, the bank doesn't get any more of those payments.
The bank might decide to buy a CDS, a sort of insurance policy. If GE never goes bankrupt, the bank is out whatever premium it paid for the CDS. If GE goes bankrupt and stops paying its bondholders, the bank gets money from whoever sold the CDS.
Who sells these CDSs? Banks, hedge funds, and AIG.
It's easy to see the attraction. Historically, bond issuers almost never go bankrupt. So, many banks and hedge funds figured they could make a fortune by selling CDSs, keeping the premium, and almost never having to pay out anything.
In fact, beginning in the late '90s, CDSs became a great way to make a lot more money than was possible through traditional investment methods. Let's say you think GE is rock solid, that it will never default on a bond, since it hasn't in recent memory. You could buy a GE bond and make, say, a meager 6 percent interest. Or you could just sell GE credit default swaps. You get money from other banks, and all you have to give is the promise to pay if something bad happens. That's zero money down and a profit limited only by how many you can sell.
Over the past few years, CDSs helped transform bond trading into a highly leveraged, high-velocity business. Banks and hedge funds found that it was much easier and quicker to just buy and sell CDS contracts rather than buy and sell actual bonds. As of the end of 2007, they had grown to roughly $60 trillion in global business.
So, what went wrong? Many CDSs were sold as insurance to cover those exotic financial instruments that created and spread the subprime housing crisis, details of which are covered here 1. As those mortgage-backed securities and collateralized debt obligations became nearly worthless, suddenly that seemingly low-risk event-an actual bond default-was happening daily. The banks and hedge funds selling CDSs were no longer taking in free cash; they were having to pay out big money.
Most banks, though, were not all that bad off, because they were simultaneously on both sides of the CDS trade. Most banks and hedge funds would buy CDS protection on the one hand and then sell CDS protection to someone else at the same time. When a bond defaulted, the banks might have to pay some money out, but they'd also be getting money back in. They netted out.
Everyone, that is, except for AIG. AIG was on one side of these trades only: They sold CDS. They never bought. Once bonds started defaulting, they had to pay out and nobody was paying them. AIG seems to have thought CDS were just an extension of the insurance business. But they're not. When you insure homes or cars or lives, you can expect steady, actuarially predictable trends. If you sell enough and price things right, you know that you'll always have more premiums coming in than payments going out. That's because there is low correlation between insurance triggering events. My death doesn't, generally, hasten your death. My house burning down doesn't increase the likelihood of your house burning down.
Not so with bonds. Once some bonds start defaulting, other bonds are more likely to default. The risk increases exponentially.
Adam goes into a lot more detail on how this affected a lot of other financial institutions. I find this ridiculous that one company could place all of their eggs into this basket without realizing the implications of a collapse. And they have the temerity to send their execs off on a $400K junket at a resort and to ask for a government bailout.