Optimal Monetary and Macroprudential Policies: Gains and Pitfalls in a Model of Financial Intermediation

We estimate a quantitative general equilibrium model with nominal rigidities and financial intermediation to examine the interaction of monetary and macroprudential stabilization policies. The estimation procedure uses credit spreads to help identify the role of financial shocks amenable to stabilization via monetary or macroprudential instruments. The estimated model implies that monetary policy should not respond strongly to the credit cycle and can only partially insulate the economy from the distortionary effects of financial frictions/shocks. A counter-cyclical macroprudential instrument can enhance welfare, but faces important implementation challenges. In particular, a Ramsey planner who adjusts a leverage tax in an optimal way can largely insulate the economy from shocks to intermediation, but a simple-rule approach must be cautious not to limit credit expansions associated with efficient investment opportunities. These results demonstrate the importance of considering both optimal Ramsey policies and simpler, but more practical, approaches in an empirically grounded model.