Monetary Policy in Troubled Times: Three Essays on Quantitative Easing in a Non-Linear Financial Environment ; Politique monétaire en période de crise : trois essais sur l'assouplissement quantitatif dans un contexte financier non-linéaire
Following the 2007 financial crisis, conventional monetary policy tools prooved insufficient to stabilize the macroeconomy and to avoid a financial disruption. As a consequence, central banks relied more heavily on unconventional monetary policy tools. This thesis aims at contributing to the understanding of unconventional monetary policy tools, focusing on the inherently non-linear nature of financial crises. In the first two chapters, we use DSGE models with occasionally binding credit constraints to account for the transitory nature of financial disruption events. In chapter one, in the case of a closed economy, we find that quantitative easing decreases the magnitude of the crisis but increases its duration. Still, when looking for intertemporal effects of quantitative easing programs, it appears that they are always welfare improving. In chapter two, when implementing quantitative easing on a two country monetary union, comes the question of how to deal with heterogeneities between members. We find that it is always better to implement nationaly tailored quantitative easing programs. Finally, an intermediate degree of financial integration proves optimal to dampen the macroeconomic consequences of the financial crisis on the overall monetary union. In the third chapter, we use a Markov-Switching Bayesian VAR model to compare the efficiency of quantitative easing in normal times versus financial crisis times. While quantitative easing programs are highly efficient during financial crisis times, we find no significant effect of these programs when the economy goes back to normal times. ; Suite à la crise financière de 2007, les outils de politique monétaire conventionnelle se sont avérés insuffisants pour stabiliser l'économie et empêcher la diffusion de la crise financière. Les banques centrales ont de fait mis en place des politiques monétaires non conventionnelles. L'objectif de cette thèse est de participer à la compréhension théorique et empirique des politique monétaires non conventionnelles en ...