We construct a fully specified extensive form game that captures competitive markets with adverse selection. In particular, it allows firms to offer any finite set of contracts, so that cross-subsidization is not ruled out. Moreover, firms can withdraw from the market after initial contract...

Public attention has focused on how the launch of the national health exchanges could impact the types of risks who initially enroll and thereby affect future premiums and enrollment. We introduce simple dynamics into a standard model of insurance under adverse selection to show that such...

This paper studies Pareto-optimal risk-sharing arrangements in a private information economy with aggregate uncertainty and ex ante heterogeneous agents. I show how to implement Pareto-optima as equilibria when agents can trade claims to consumption contingent on aggregate shocks in financial...

This paper studies optimal dynamic tax policy under the threat of political reform. A policy will be reformed ex post if a large enough political coalition supports reform; thus, credible policies are those that will continue to attract enough political support in the future. If the only...

This paper analyzes Pareto optimal non-linear taxation of profits and labor income in a private information economy with endogenous firm formation. Individuals differ in both their skill and their cost of setting up a firm, and choose between becoming workers and entrepreneurs. I show that a tax...

We consider optimal redistribution in a model where individuals can self-select into one of several possible sectors based on heterogeneity in a multidimensional skill vector. We first show that when the government does not observe the sectoral choice or underlying skills of its citizens, the...

We develop a unifying framework for optimal income taxation in multi-sector economies with general patterns of externalities. Agents in this model are characterized by an N-dimensional skill vector corresponding to intrinsic abilities in N potentially externality-causing activities. The private...

Recent policy proposals have suggested taxing top incomes at very high rates on the grounds that some or all of the highest wage earners are engaged in socially unproductive or counterproductive activities, such as externality imposing speculation in the financial sector. To address this, we...

We study the effects of 'balance billing', i.e., allowing physicians to charge a fee from patients in addition to the fee paid by Medicare. First, we show that on pure efficiency grounds the optimal Medicare fee under balance billing is zero. An active Medicare policy thus can only be justified...