In 2007-2008, this was the case for a class of securities based on residential mortgages in the United States (RMBS, or residential mortgage-backed securities). During the boom phase, these securities were sold as risk-free, on the assumption that US house prices could not decline, as this had never happened before in peacetime.
2007—2008年，美国住宅按揭抵押证券（RMBS）就出现了这种情形。在繁荣阶段，这些证券被认为是无风险的，人们假设美国房价永不会下跌，因为和平时代还没有发生过这种状况。