We propose a model of a risky mortgage-lending market in which we take explicit account of heterogeneity in household borrowing conditions, by introducing two borrower types: one with a low loan-to-value (LTV) ratio, one with a high LTV ratio, calibrated to U.S. data. We use such framework to study a deleveraging shock, modeled as an increase in housing investment risk, that falls more strongly on, and produces a larger contraction in credit for high-LTV type borrowers, as in the data. We find that this deleveraging experience produces significant aggregate effects on output and consumption, and that the contractionary effects are orders of magnitudes higher in a model version that takes account of borrower heterogeneity, compared to a more standard model version with a representative borrower. / Series: Department of Economics Working Paper Series

We study the impact of macroprudential policies using a novel model which takes into account households´ ability to borrow under different loan-to-value ratios which are tied to their collateral values. Such model generates a larger amplification in real and financial variables, compared to standard models that assume homogeneity in the leveraging and deleveraging process. Conditional on this model, we consider the implications of macroprudential policies that aim to lean against an excessive credit cycle. In particular, we allow macroprudential authorities to tighten excessive lending to higher leveraged households, whose riskiness had been evaluated too optimistically. We find thata policy that targets only the group of households that most strongly deleveraged after an adverse idiosyncratic housing investment risk shock, is welfare-improving at social and individual levels, relative to a macroprudential policy which targets all households in the economy. / Series: Department of Economics Working Paper Series