''How high-risk borrowers contaminated securities backed by prime mortgages. A story about the financial crisis and contagion''

"In the 1980s we had trickle-down economics. During the first half of the 2000s, we had trickle-up credit scoring. 

Before you yawn (or stop reading), consider that credit score inflation was 

(1) a real phenomenon, and 

(2) helps explain why, when the crisis hit, the market for bonds backed by supposedly high quality prime mortgages suffered from the same kinds of liquidity problems as subprime backed MBS." 


a must read......from wall street law blog...