Monetary Policy Uncertainty and Economic Fluctuations at the Zero Lower Bound

We propose a TVP-VAR with stochastic volatility for the unemployment rate, core inflation and the federal funds rate augmented with survey-based interest rate expectations and uncertainty and a FAVAR with a wider set of observable variables and alternative monetary policy measures in order to explore U.S. monetary policy, accounting for the zero lower bound. We find that a rise in monetary policy uncertainty increases unemployment and lowers core inflation; the effects on unemployment in particular are robust (a gradual 0.4 percentage point increase), lasting more than two years after the initial shock. Interest rate uncertainty shocks explain a significant portion of macro fluctuations, particularly after the 2007-09 global financial crisis contributing to push the unemployment rate one percentage point higher during the early phase of the subsequent recovery. Furthermore, we find that higher interest rate uncertainty makes forward guidance shocks (but also federal funds rate shocks) less effective at moving unemployment and core inflation. We also posit a theoretical model to provide the structural backbone for our empirical results, via an “option value” channel. Theory yields sizeable real effects and a muted monetary policy transmission mechanism as firms choose to postpone investment decisions in response to heightened interest rate uncertainty.