I appreciate the technical correction in the difference between derivatives and structured debt backed securities, I did not know of this important distinction.

I appreciate the technical correction in the difference between derivatives and structured debt backed securities, I did not know of this important distinction. In any case I was responding to the contention that financial crisis of 2008 was driven by "overly enthusiastic" retail bank style lending practices. By my lay persons reasoning it seems clear that the new forms of mortgage backed securities played a significant role in perpetuating the mortgage bubble, as their complicated structures enabled,at the least, shady practices on the part of the ratings agencies, loan originators, and banks. Derivatives did have some role in the crisis, as they were at the root of the highest profile firm failure, AIG (credit default swaps).