Joint Discussion Paper Series in Economics 09-2018
We study the role of monetary policy for the dynamics of U.S. mortgage debt, which is the largest component of household indebtedness. A timevarying parameter VAR model allows us to study the variation in the mortgage debt sensitivity to monetary policy. We find that an identically-sized policy shock became less effective over time. We use a DSGE model to show that a fall in the share of adjustable-rate mortgages (ARMs) could replicate this finding. Calibrating the model to the drop in the ARM share since the 1980s yields a drop in the sensitivity of housing debt to monetary policy which is quantitatively similar to the VAR results. A sacrifice ratio for mortgage debt reveals that a policy tightening directed towards reducing household debt became more expensive in terms of a loss in employment. Counterfactuals show that this result cannot be attributed to changes in monetary policy itself. The results are consistent with the "mortgage rate conundrum" found by Justiniano et al. (2017) and have strong implications for policy.
mortgage debt monetary policy deleveraging time-varying VAR DSGE