Three essays on macroeconomics and wealth distribution

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Thesis type
(Thesis) Ph.D.
Date created
Author: Lei, Xiaowen
My thesis focuses on macroeconomics and monetary policy, with a concentration on belief heterogeneity, household portfolio choice and wealth distribution. I also work on real option models in monetary policy. The first chapter of my thesis, entitled “Wait and See" Monetary Policy , was coauthored with my classmate Michael Tseng, and is recently published in Macroeconomic Dynamics. The paper develops a model of the optimal timing of interest rate changes. With fixed adjustment costs and ongoing uncertainty, changing the interest rate involves the exercise of an option. Optimal policy therefore has a “wait-and-see" component, which can be quantified using option pricing techniques. We show that increased uncertainty makes the central bank more reluctant to change its target interest rate, and argue that this helps explain recent observed deviations from the Taylor Rule. The second chapter is entitled Risk, Uncertainty and the Dynamics of Inequality, which is co-authored with my senior supervisor Professor Kenneth Kasa, and is recently published in Journal of Monetary Economics. That paper studies the dynamics of wealth inequality in a continuous-time Blanchard/Yaari model. Its key innovation is to assume that idiosyncratic investment returns are subject to (Knightian) uncertainty. In response, agents formulate ‘robust’ portfolio policies (Hansen and Sargent (2008)). These policies are non-homothetic; wealthy agents invest a higher fraction of their wealth in uncertain assets featuring higher mean returns. This produces an endogenous feedback mechanism that amplifies inequality. It also produces an accelerated rate of convergence, which resolves a puzzle recently identified by Gabaix, Lasry, Lions, and Moll (2016). The third chapter, entitled Information and Inequality, studies wealth inequality in a continuous-time Blanchard/Yaari model with idiosyncratic investment returns. Its key innovation is to assume that individuals can buy information. Information reduces uncertainty about the unknown mean investment return. If the coefficient of relative risk aversion exceeds unity, reduced estimation risk encourages investment in higher yielding risky assets. As a result, endogenous information acquisition amplifies wealth inequality. Relatively wealthy individuals buy more information, which leads them to invest more in higher yielding assets, which then makes them even wealthier.
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Supervisor or Senior Supervisor
Thesis advisor: Kasa, Ken
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