Optimal Monetary Policy with Countercyclical Credit Spreads
在新凯恩斯DSGE模型中引入银行关系借贷，发现借款人的银行特定习惯导致逆周期信用利差，使最优货币政策显著偏离价格稳定目标，且福利成本随信用市场习惯和银行市场势力增强而上升。
Abstract We study optimal monetary policy in a New‐Keynesian Dynamic Stochastic General Equilibrium (DSGE) model with a credit channel and relationship lending in banking. We show that borrowers' bank‐specific (deep) habits give rise to countercyclical credit spreads, which, in turn, make optimal monetary policy depart substantially from price stability, under both discretion and commitment. Our analysis shows that the welfare costs of setting monetary policy under discretion (with respect to the optimal Ramsey plan) and of using simpler suboptimal policy rules are strictly increasing in the magnitude of deep habits in credit markets and market power in banking.