Description: This crisis first started with subprime loans and quickly morphed into a credit crisis that eventually engulfed a lot of financial institutions around the world. If a AAA were really a AAA, this crisis would probably have been contained and localized. As the crisis developed, evidence emerged from the shadows that revealed the questionable quality of some AAA-rated MBS or ABS. Subprime loans were the weakest link. As the credit boom came to an end and the economy slowed down further, the Alt-A, prime and credit card loans were also affected. The subprime crisis is only the symptom of a much larger underlying problem. Both consumers and corporations were overleveraged.

Description: This article addresses the difficulties of risk modeling in a poor economic environment. The problems include imperfect vendors of data, facing events that have never occurred before, unpredictable consumer behavior, conflicting data sources, and AAA credit doesn't always mean AAA.