Using a novel source of quasi-experimental variation in interest rates, we develop a new approach to estimating the Elasticity of Intertemporal Substitution (EIS). In the U.K., the mortgage interest rate features discrete jumps—notches—at thresholds for the loan-to-value (LTV) ratio. These notches generate large bunching below the critical LTV thresholds and missing mass above them. We develop a dynamic model that links these empirical moments to the underlying structural EIS. The average EIS is small, around 0.1, and quite homogeneous in the population. This finding is robust to structural assumptions and can allow for uncertainty, a wide range of risk preferences, portfolio reallocation, liquidity constraints, present bias, and optimization frictions. Our findings have implications for the numerous calibration studies that rely on larger values of the EIS.

We investigate the effect of house prices on household borrowing using administrative mortgage data from the United Kingdom and a new empirical approach. The data contain household-level information on house prices and borrowing in a panel of homeowners, who refinance at regular and quasi-exogenous intervals. The data and setting allow us to develop an empirical approach that exploits house price variation coming from the idiosyncratic and exogenous timing of refinance events around the Great Recession. We present two main results. First, there is a clear and robust effect of house prices on borrowing. Second, the effect of house prices on borrowing can be explained largely by collateral effects. We study the collateral channel through a multivariate and nonparametric heterogeneity analysis of proxies for collateral and wealth effects.