Essays in financial economics

Abstract

This thesis consists of three essays that theoretically and empirically investigate the asset pricing and macroeconomic implications of uncertainty shocks, propose new measures for model robustness, explain the joint dynamics on equity excess returns and real exchange rates. In the first chapter, I show that the effect of uncertainty shocks on asset prices and macroeconomic dynamics depends on the degree of risk sharing in the economy and the origin of uncertainty. I develop a general equilibrium model with imperfect risk sharing and two sources of uncertainty shocks: (i) cash-flow uncertainty shocks, which affect the idiosyncratic volatility of firms' productivity, and (ii) growth uncertainty shocks, which affect the idiosyncratic variability of firms' investment opportunities. My model deviates from the neoclassical setting in one respect: firms' investment policies are set by the experts who are subject to a moral hazard problem and thus must maintain an non-diversified ownership stake in the firm. As a result, risk sharing between experts and other investors is imperfect. Limited risk sharing distorts equilibrium investment choices, firm valuation, and prices of risk in equilibrium relative to the frictionless benchmark. In the calibrated model, the risk premium on growth uncertainty shocks is negative under poor risk sharing conditions and positive otherwise. Moreover, the cross-sectional spread in valuations between value and growth stocks loads positively on the growth uncertainty shocks under poor risk sharing conditions and negatively otherwise. Empirical tests support these predictions of the model. The second chapter is based on the joint work Chen, Dou, and Kogan (2015), in which we propose a new quantitative measure of model fragility, based on the tendency of a model to over-fit the data in sample with poor out-of-sample performance. We formally show that structural economic models are fragile when the cross-equation restrictions they impose on the baseline statistical model appear excessively informative about combinations of model parameters that are otherwise difficult to estimate. We develop an analytically tractable asymptotic approximation to our fragility measure which we use to identify the problematic parameter combinations. Using these asymptotic results, we diagnose fragility in asset pricing models with rare disasters and long-run consumption risk. The third chapter is based on the joint work Dou and Verdelhan (2015), which presents a two-good, two-country real model that replicates the basic stylized facts on equity excess returns and real interest rates. In the model, markets are incomplete. In each country, workers cannot participate in financial markets whereas investors trade domestic and foreign stocks, as well as an international bond. The investors' asset positions are subject to a borrowing constraint, along with a short-selling constraint on equity. Foreign and domestic agents differ in their elasticity of inter temporal substitution and in their risk-aversion. A time-varying probability of a global disaster implies time-varying risk premia in asset markets, and therefore large and time-varying expected valuation effects on international asset positions. The model highlights the role of market incompleteness and heterogeneity across countries in accounting for the volatility of equity and debt international capital flows.