Essays on Financial Stability and Monetary Policy

This thesis consists of three self-contained chapters.
Chapter I. The first chapter develops a dynamic general equilibrium model which includes financial intermediation and endogenous financial crises. Consistent with the data, financial crises occur out of prolonged (credit) boom periods and are initiated by a moderate adverse shock. The mechanism which gives rise to boom-bust episodes around financial crises is based on an interaction between the maturity mismatch of the financial sector and an agency problem which results in procyclical lending. I show how to model these features in a tractable way, giving a realistic representation of the financial sector's balance sheet and its lending behavior. The chapter provides empirical evidence on the behavior of the U.S. financial sector's market leverage which is (i) acyclical, (ii) rose mildly prior to the Great Recession, and (iii) increased sharply during the crisis; the model is consistent with these empirical facts. It also predicts and replicates the Great Recession, when confronted with a historical series of structural shocks. Finally, the framework is extended to include price rigidities, nominal debt contracts, and monetary policy. Within this version, I analyze the impact of monetary policy on financial stability and show that a U-shaped pattern of the policy target rate is most likely to increase financial instability.
Chapter II. The second chapter models the economy as a time varying vector autoregression, consisting of economic and financial variables. The interest lies in the time varying response of these variables to a monetary policy shock. Monetary policy shocks are identified as the surprise component in policy announcements extracted from price changes in Federal Funds futures around such announcements. These monetary policy surprises enter the model as an exogenous variable. The framework is used to obtain evidence on the time varying response of stock prices to the monetary policy surprises. Stock prices always persistently decrease following a monetary tightening and more strongly than fundamentals imply - with an increase in risk-premia accounting for the difference. However, the response of stock prices varies over time. They decrease less during a boom and a perceived bubble period than during a recession. The findings suggest that so-called "leaning against the wind policies" may be ineffective since stock prices are less responsive during periods when such policies would disinflate asset bubbles using contractionary monetary policy.
Chapter III. The third chapter augments a monetary dynamic general equilibrium model with a bubble as considered in [Miao_Wang_2015]. A bubble may exist in firms' stock market values and firms borrow against their inflated stock market values. Within this framework, I analyze the relation between monetary policy and the bubble. I find that contractionary monetary policy decreases the bubble which tightens borrowing constraints and amplifies the reaction of investment and output. These results are in contrast to the ones in Gali (2014) who considers a bubble of the classic rational type and finds that contractionary monetary policy can increase bubbles.

Advisor: Ellison, M