Essays on macroeconomics with financial frictions

Abstract

The first chapter of this thesis, joint with Angela Abbate analyses the importance of the risk-taking channel for monetary policy. To answer this question, we develop and estimate a quantitative monetary DSGE model where banks choose excessively risky investments, due to an agency problem which distorts banks’ incentives. As the real interest rate declines, these distortions become more important and excessive risk taking increases, lowering the efficiency of investment. We show that this novel transmission channel generates a new and quantitatively significant monetary policy trade-off between inflation and real interest rate stabilization: it is optimal for the central bank to tolerate greater inflation volatility in exchange for lower risk taking. The second chapter develops a quantitative model of sovereign default with endogenous default costs to propose a novel answer to the question why governments repay their debt. In the model domestic banks are exposed to sovereign debt. Hence sovereign default causes large losses for the banks, which translate into a financial crisis. The government trades these costs off against the advantage of not repaying international investors. Besides replicating business cycle moments, the model is able to generate not only output costs of a realistic magnitude, but also endogenously predicts that default is followed by a period during which no new foreign lending takes place. The duration of this period matches empirical estimates. The third chapter outlines a method to reduce the computationally necessary state space for solving dynamic models with global methods. The idea is to replace several state variables by a summary state variable. This is made possible by anticipating future choices that depend on one of the replaced variables. I explain how this method can be applied to a simple portfolio choice problem.