Uncertainty, Fiscal, and Financial Shocks in a Nonlinear World: Empirical Investigations

This thesis investigates the macroeconomic effects of uncertainty, fiscal and financial shocks on the US economy. It is set out in four self-contained chapters, which use linear and nonlinear (Smooth Transition) Vector Autoregressive models, and Local Projections techniques, to extend the literature, and evaluate the importance of different transmission channels of macroeconomic shocks suggested by theoretical models. The main results show that these shocks have nonlinear effects over the business cycle, i.e., the response of macro aggregates following the shocks are statistically different depending on whether the economy is in a recession or expansion. From a theoretical perspective, this finding highlights the importance of accounting for nonlinearities when developing macroeconomic models. From a policy perspective, the results suggest the implementation of nonlinear policy rules to properly deal with macroeconomic instability.