Optimal Macroprudential Policy

This paper introduces financial market frictions into a standard New Keynesian model through search and matching in the credit market. Under such financial market frictions, a second-order approximation of social welfare includes a term involving credit, in addition to terms for inflation and consumption. As a consequence, the optimal monetary and macroprudential policies must contribute to both financial and price stability. This result holds for various approximated welfares that can change corresponding to macroprudential policy variables. The key features of optimal policies are as follows. The optimal monetary policy requires keeping the credit market countercyclical against the real economy. Commitment in monetary and macroprudential policy, rather than approximated welfare, justifies history dependence and pre-emptiveness. Appropriate combinations of macroprudential and monetary policy achieve perfect financial and price stability.2012～2016年度科学研究費補助金[基盤研究(S)]「長期デフレの解明」(研究代表者 東京大学経済学研究科・渡辺努, 課題番号：24223003