The Zero Lower Bound: Implications for Modelling the Interest Rate

The time-varying parameter vector autoregressive (TVP-VAR) model has been used to successfully model interest rates and other variables. As many short interest rates are now near their zero lower bound (ZLB), a feature not included in the standard TVP-VAR specification, this model is no longer appropriate. However, there remain good reasons to include short interest rates in macro models, such as to study the effect of a credit shock. We propose a TVP-VAR that accounts for the ZLB and study algorithms for computing this model that are less computationally burdensome than others yet handle many states well. To illustrate the proposed approach, we investigate the effect of the zero lower bound of interest rate on transmission of a monetary shock.