Three essays in monetary and financial economics.

Summary The first chapter analyzes the impact of central clearing of swaps, which has been mandatory since 2013, on the derivatives activity of U.S. banks. A portion of treated banks, i.e., banks that are not eligible for the "end-user exception," reallocate their portfolios by substituting OTC interest rate options for OTC interest rate swaps. This suggests that these banks may be engaging in regulatory arbitrage. The second chapter incorporates a natural interest rate with a stochastic trend into a New Keynesian model and studies how this changes optimal monetary policy. It shows that systematic increases in the optimal inflation rate are justified in response to negative shocks to the long-run level of the natural rate, once it falls below 1 per cent. Nevertheless, a rule that targets a constant price level continues to provide a good approximation of optimal policy as long as the long-run level of the natural rate remains positive. The third chapter studies the link between microeconomic uncertainty, defined as the dispersion of idiosyncratic productivity levels, and the allocation of credit among firms. It analyzes the equilibrium of a secured debt market where banks and financial investors interact in the presence of adverse selection and signaling. The model predicts that an increase in micro uncertainty can generate a change in the information regime and result in a credit crunch. In this case, high micro uncertainty restores the optimal allocation, as banks only finance good quality projects.