Discussion Paper Series 2008-E-8

Optimal Monetary Policy under Staggered Loan Contracts

Yuki Teranishi

The first aim of the paper is to investigate a new source of economic stickiness, staggered nominal loan interest rate contracts between a private bank and a firm under the monopolistic competition. We introduce this staggered loan contract mechanism with micro-foundation based on agent's optimized behaviors into a standard New Keynesian model in a tractable way. Simulation results show that staggered loan contracts play an important role in determining both the amplitude and the persistence of economic fluctuations. The second aim of the paper is to analyze optimal monetary policy in this environment with staggered loan contracts. To this end, we derive an approximated microfounded-welfare function in the model. Unlike the loss functions derived in other New Keynesian models, this model's welfare function includes a term that measures the first order difference in loan interest rates, which requires reduction of the magnitude of policy interest rate changes in the welfare itself. We derive the optimal monetary policy rule when the central bank can commit to its policy in the timeless perspective. One implication of the optimal policy rule is that the central bank has the incentive to smooth the policy interest rate. This empirically realistic conclusion can be seen in our simulation results.

Keywords: Staggered Loan Interest Rate Contract; Optimal Monetary Policy; Economic Fluctuation

Views expressed in the paper are those of the authors and do not necessarily reflect those of the Bank of Japan or Institute for Monetary and Economic Studies.

Copyright © 2008 Bank of Japan All Rights Reserved.

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