The document describes the creation and selling of mortgage-backed securities and collateralized debt obligations (CDOs) during the subprime mortgage crisis. It shows an investment bank taking risky subprime mortgages, pooling them into CDOs, and selling the CDO tranches to investors while misrepresenting the risk. When the borrowers began to default, the investors were not paid as promised, contributing to the financial crisis. The bank blames the rating agencies, insurers, and faulty assumptions for investors' losses rather than taking responsibility.