Mortgage-Backed Securities and the Financial Crisis of 2008: a Post Mortem
We examine the payoff performance, up to the end of 2013, of non-agency residential mortgage-backed securities (RMBS), issued up to 2008. We have created a new and detailed data set on the universe of non-agency residential mortgage backed securities, per carefully assembling source data from Bloomberg and other sources. We compare these payoffs to their ex-ante ratings as well as other characteristics. We establish seven facts. First, the bulk of these securities was rated AAA. Second, AAA securities did ok: on average, their total cumulated losses up to 2013 are 2.3 percent. Third, the subprime AAA-rated segment did particularly well. Fourth, later vintages did worse than earlier vintages, except for subprime AAA securities. Fifth, the bulk of the losses were concentrated on a small share of all securities. Sixth, the misrating for AAA securities was modest. Seventh, controlling for a home price bust, a home price boom was good for the repayment on these securities. Together, these facts provide challenge the conventional narrative, that improper ratings of RMBS were a major factor in the financial crisis of 2008.
This research has been supported by the NSF grant SES-1227280. We are grateful to the research assistance by Avigail Kifer at a very early, but crucial first stage of this paper. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.
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