Monetary Policy Transmission under Zero Interest Rates: An Extended Time-Varying Parameter Vector Autoregression Approach

This paper attempts to explore monetary policy transmission under zero interest rates by explicitly incorporating the zero lower bound (ZLB) of nominal interest rates into the time-varying parameter structural vector autoregression model with stochastic volatility (TVP-VAR-ZLB). Nominal interest rates are modeled as censored variables with Tobit-type non-linearity and are incorporated into the TVP-VAR framework. For estimation, an efficient Markov chain Monte Carlo (MCMC) method is constructed in the context of Bayesian inference. The model is applied to Japanese macroeconomic data, including the periods of the zero interest rates policy and the quantitative easing policy. The empirical results show that a dynamic relationship between monetary policy and macroeconomic variables operates through changes in medium-term interest rates rather than policy interest rates under the ZLB. However, the explicit consideration of the ZLB does not otherwise affect macroeconomic dynamics.