A number of stylized facts have been documented about the extensive margin of trade - which firms export, and how many products they send to how many destinations. We argue that the sparse nature of trade data is crucial to understanding these stylized facts. Typically the number of observations...

I show that multiple equilibria are a general property of economies under full monetary policy discretion. Three simple conditions are sufficient to rule out, generically, a unique equilibrium in a static economy. The key departure from Barro and Gordon (1983) is to consider bounded welfare...

We consider a very general class of public finance problems that encompasses Ramsey models of optimal taxation as well as economies with limited commitment, private information, and political economy frictions. We identify a sufficient condition to rule out permanent intertemporal distortions at...

A number of stylized facts have been documented about the extensive margin of trade---which firms export, and how many products they send to how many destinations. We argue that the sparse nature of trade data is crucial to understanding these stylized facts. Typically the number of...

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...

We model an environment in which different vintages of capital with their different productivities coexist. A reduction in the cost of investment induces investment in new capital which raises both measured capital and measured productivity simultaneously. We calibrate this model to...

Infinitely repeated games have been used to argue that reputation can substitute for commitment in monetary policymaking. A drawback of this approach is that it implies multiple equilibria. I argue that nominal asset prices can be used as an equilibrium selection mechanism. First, I introduce...

We argue that labor mobility does not lead to a ''race to the bottom,'' where countries drastically cut redistributive transfers in order to attract skilled workers. The basis of our argument is that these cuts are not credible policies. We propose a two country model where competition for...