Job Market Paper
Financial Crises, Debt Maturity, and Capital Controls [PDF]
This paper studies debt portfolio choice and optimal capital control policy in an open economy with financial frictions. I construct a new measure of capital control changes and document two novel stylized facts during financial crises: (i) capital inflow controls are tightened, and (ii) short-term inflow controls are tightened more than long-term inflow controls. Motivated by these empirical findings, I extend the model of international borrowing with collateral constraint to allow for multiple debt maturities. As in the single-maturity version of the model, the equilibrium exhibits overborrowing because, due to a pecuniary externality, private agents undervalue the cost of financial liabilities that demand repayment in future constrained states. The key insight of the multiple-maturity model is that overborrowing in short-term debt is especially severe because the repayment of short-term liabilities is larger than that of long-term liabilities in future constrained states, resulting in greater cost undervaluation of short-term financial obligations. To counteract these inefficiencies, the model justifies a set of maturity-dependent capital controls. In line with the data, the model predicts a tightening of capital controls tilted toward short maturities during financial crises. When calibrated to Argentine data, the model reproduces the observed dynamics of debt portfolios, and the short-term targeting of capital controls during crises. The optimal capital-control policy reduces the frequency of crises by half and generates sizable welfare improvements.
Real Exchange Rate and External Balance: How Important are Price Deflators?
[PDF | IMF WP| slides] (with JaeBin Ahn, Rui Mano)
Among real exchange rates deflated by various prices (CPI-, GDP deflator-, Unit Labor Cost-), only unit-labor-cost-based one shows significant negative correlation with external balance, and it can be rationalized by price and wage rigidity and intermediate goods trade.
Extensive Margin Adjustment of Multi-product Firms and Stock Returns
Work in Progress
Teaching (teaching assistant)
Financial Economics, Columbia University, [2017, 2016, 2014, 2013]
Money and Banking, Columbia University, [spring 2016]
Corporate Finance, Columbia University, [2014, 2015]
Globalization, Markets and the Changing Economic Landscape (EMBA), Columbia University, [summer 2014]
Advanced Macroeconomics, Peking University, 
Mathematical Analysis, Wuhan University, [2007 - 2009]