Definition: Mortgage-backed securities which often earned blue-chip grades from rating agencies but became toxic when the sub-prime crisis hit.
Usage: "AIG was pushed to the brink of bankruptcy by derivative-based guarantees it sold on mortgages and more complex mortgage-related products known as collateralized debt obligations. AIG suffered huge losses on these exposures as the housing market slumped, triggering downgrades by ratings agencies." (Marketwatch, Oct. 3, 2008)