cliff risk
n.— «CDOs-squared are often referred to as being subject to the so-called “cliff” risk, a phenomenon where the tranche gets wiped out quickly once losses reach it.» —“CDOs-Squared Demystified” by Nomura Securities International, Michiko Whetten, Mark Adelson Securitization.net Feb. 4, 2005. (source: Double-Tongued Dictionary)