I still don’t really have my head around this, so let me tell you what I think happened and you, if you want, can correct any mistakes.
Banks sold mortgages to consumers, many of whom were high-risk, a.k.a. sub-prime. Many of these customers chose adjustable rate mortgages in order to get favorable rates on the theory that the value of their home would continue to increase (home values were on fire after all and they aren’t making more real estate). Some of the borrowers were the victims of predatory lending (the idea of which is that you can bleed a borrower dry and when he can no longer pay, you get the collateral back which you can sell to make a profit on the whole deal). Other borrowers were encouraged to misstate their ability to pay the loan back, resulting in the so-called “liar loans” (the idea being that the lender would sell the debt and make it someone else’s problem).
Initial lenders packaged up loans, some of which were likely to be paid back, and some of which weren’t, into securities called collateralized debt obligations. These were further broken up and repackaged in an attempt to spread the risk around. I don’t know what the face value at maturity of these CDOs were.
These securities were risky, so to make them investment-grade, they were insured, mostly by AIG. Once that was done, ratings agencies were free to rate them AAA or whatever, neglecting a run on AIG. AIG figured that all the borrowers wouldn’t go belly up at once, so they were able to leverage their position.
When interest rates rose, many subprime borrowers could no longer make their payments. At the same time, new borrowers were unable or unwilling to take on loans at the higher rates. Borrowers who could not afford their homes anymore found that the pool of buyers had shrunk, lowering the value of the homes. Many went underwater and many were foreclosed upon. The default rate increased and, crucially, the effect was widespread and so the risk was not as diversified as expected.
The CDOs became illiquid (i.e. “toxic”), because no one could adequately assess the risk due to the complicated mixture of mortgages that comprised them. I am not sure why. After all, someone had to figure out how to take the mortgage payments from the borrower and funnel that money to the right places.
If the CDOs were illiquid, it doesn’t exactly mean they are worthless, does it? After all, many borrowers whose mortgages were wrapped up in CDOs continued to make the payments and therefore interest continued to be payed on them, didn’t it? For whatever reason, claims were made to AIG that the CDOs were no good. AIG couldn’t cover the losses. Many institutions had too much exposure to CDOs and were suddenly strapped for cash. The rest is history.
What have I failed to comprehend?
Thanks,
Rob