Many of the facts about the extensive margin of trade—which firms export, and how many products are sent to how many destinations—are consistent with a surprisingly large class of trade models because of the sparse nature of trade data. We propose a statistical model to account for sparsity,...

Cross-country income gaps are large in the data. Can observed investment prices account for these gaps? Our model adds an extensive margin to the neoclassical growth model by allowing for entry of firms. When combined with a “returns to variety” effect, our model provides an amplification...

This paper studies the long run properties of intertemporal distortions in a broad class of second best economies. Our unified framework encompasses and extends many well known models, such as variants of the Ramsey taxation model with aggregate or idiosyncratic risk, and economies with...

We consider a very general class of public finance problems that encompasses the Ramsey model of optimal taxation as well as economies with limited commitment, private information, and political economy frictions, and allows for incomplete markets. We identify a sufficient condition to rule out...

We ask whether worker mobility has undermined the ability of U.S. states to redistribute income. We build a tractable model where both migration decisions and redistribution policies are jointly determined. Our model features a large number of heterogeneous regions and skilled and unskilled...

Optimal capital taxes may be positive in the steady state in Ramsey models with an incomplete set of factor taxes. I show this possibility crucially depends on how fiscal policy is constrained at date t = 0. If the government is barred from manipulating the value of initial assets, the...

We analyze the joint determination of income redistribution and migration flows across fiscally independent regions. In our model, regional governments lack commitment so their policy announcements must be credible, and redistribution between skilled and unskilled workers is bounded by...