The authors develop an equilibrium valuation model that incorporates optimal default to show how mortgage yields and lender recovery rates on defaulted mortgages depend on initial loan-to-value (LTV) ratios. The analysis treats both the frictionless case and the case in which borrowers and lenders incur deadweight costs upon default. The model is calibrated using data on California mortgages. Given reasonable parameter values, the model does a surprisingly good job fitting the risk premium in the data for high LTV mortgages. Thus, from an ex ante perspective, the authors do not find strong evidence of systematic underpricing of default risk in the run-up to the housing market crisis. Charts and tables.

Valuation of mortgage-backed securities requires blending empirical analysis of borrower behavior and mathematical modeling of interest rates and home prices, with recognition of various prices of risk and uncertainty. This book offers a detailed description of the sophisticated theories and advanced methods used for the real-world valuation of MBS.