Constrained Pseudo-Market Equilibrium

We propose a pseudo-market solution to resource allocation problems subject to constraints. Our treatment of constraints is general: including bihierarchical constraints due to considerations of diversity in school choice, or scheduling in course allocation; and other forms of constraints needed to model, for example, the market for roommates, combinatorial assignment problems, and knapsack constraints. Constraints give rise to pecuniary externalities, which are internalized via prices. Agents pay to the extent that their purchases affect the value the of relevant constraints at equilibrium prices. The result is a constrained-efficient market-equilibrium outcome. The outcome is fair to the extent that constraints treat agents symmetrically. (JEL D47, D61, D63, I11, I21)

Capital Controls: Theory and Evidence

This paper synthesizes recent advances in the theoretical and empirical literature on capital controls. We start by observing that international capital flows have both benefits and costs, but some of these are not internalized by individual actors and thus constitute externalities. The theoretical literature has identified pecuniary externalities and aggregate demand externalities that respectively contribute to financial instability and recessions. These externalities provide a natural rationale for countercyclical capital controls that lean against boom and bust cycles in international capital flows. The empirical literature has developed several measures of capital controls to capture different aspects of capital account openness. We evaluate the strengths and weaknesses of different measures and provide an overview of the empirical findings on the effectiveness of capital controls in addressing the externalities identified by the theory literature, that is, in reducing financial fragility and enhancing macroeconomic stability. We also discuss strategies to deal with the endogeneity of capital controls in such statistical exercises. We conclude by providing an overview of the historical and current debates on the role of capital controls in macroeconomic management and their relationship to the academic literature. (JEL D62, F32, F33, F38, F44)

Optimal Taxation with Private Insurance

We derive a fully nonlinear optimal income tax schedule in the presence of private insurance. We fill the gap in the literature by studying the optimal tax formula with a comprehensive structure of the private markets—including incomplete markets models— both theoretically and quantitatively. As in the standard taxation literature without private insurance (e.g., Saez (2001)), the optimal tax formula can still be expressed in terms of standard sufficient statistics. With private insurance, however, the formula involves additional terms that reflect how the private market interacts with public insurance. For example, the optimal tax formula should also consider asset distribution and pecuniary externalities as well as the welfare effects of borrowing constraints.

Financial Stability Regulation under Borrowing and Liquidity Externalities

We study financial stability regulation in an environment with pecuniary externalities and where banks face both a liability choice (between private money creation and long-term borrowing) and an asset choice (between liquid and illiquid investments). Return risk on illiquid assets gives rise to liquidity risk, because banks that learn to have low future returns find themselves unable to roll over “money-like” debt. Privately optimal borrowing and investment decisions by banks lead, in general, to socially inefficient outcomes. The nature of inefficiency depends critically on the degree to which liquidity risk is systemic: When risk is highly systemic, banks hold the socially optimal amount of liquid assets, but create an excessive amount of money and overinvest in risky assets; when risk is not highly systemic, banks hold too little liquidity, create insufficient private money, and underinvest in risky assets. Quantity- and price-based regulations to address the identified inefficiencies are discussed.

Optimal Macroprudential Policy and Asset Price Bubbles

An asset bubble relaxes collateral constraints and increases borrowing by credit-constrained agents. At the same time, as the bubble deflates when constraints start binding, it amplifies downturns. We show analytically and quantitatively that the macroprudential policy should optimally respond to building asset price bubbles non-monotonically depending on the underlying level of indebtedness. If the level of debt is moderate, policy should accommodate the bubble to reduce the incidence of a binding collateral constraint. If debt is elevated, policy should lean against the bubble more aggressively to mitigate the pecuniary externalities from a deflating bubble when constraints bind.

Public Input Provision in Asymmetric Regions with Labor Market Imperfections

This paper examines efficiency in public input provision in two large regions with labor market imperfections. Because employment and pecuniary externalities are associated with public input provision, the provision level exceeds the optimal amount under the presence of wage rigidities in the capital-exporting jurisdiction if only head taxes are used to finance government expenditures. Efficiency in public input provision will remain ambiguous in the capital-importing jurisdiction unless a specific functional form is assumed for the production technology. The constrained efficient provision with public inputs can be restored with an additional tax (subsidy) on capital that is used to strategically influence the interest rate on the common capital market and to increase employment by attracting foreign capital.