toxic assets means: The term is used to describe assets such as collateralized debt obligations and mortgage-backed securities that were difficult or inaccessible to value during the 2007-2009 economic recession. These securities can lose their value quickly if the value of their underlying assets drops significantly. This could be exacerbated by a lack of liquidity or transparency of price, which could result in significant write-downs for the holders and consequently losses. (in Stock Market Dictionary)