Products with negative externalities are often subject to regulations that limit competition. The single-product case may suggest that it is irrelevant for aggregate welfare whether output is restricted via corrective taxes or limiting competition. However, when products are differentiated...

We study the welfare costs of markups in a dynamic model with heterogeneous firms and endogenously variable markups. We find that the welfare costs of markups are large. We decompose the costs of markups into three channels: (i) an aggregate markup that acts like a uniform output tax, (ii)...

This paper analyzes features of perfect taxation also known as optimal taxation when one or more private markets is imperfectly competitive. Governments with perfect information and access to lump-sum taxes can provide corrective subsidies that render outcomes efficient in the presence of...

There has been keen interest in recent years in environmentally motivated or 'green' tax reforms. This paper employs analytical and numerical general equilibrium models to investigate the costs of such reforms, concentrating on the question of whether these costs can be eliminated when revenues...

Does taxation for public goods generally involve a distortionary cost? Are Pigouvian taxes desirable because they raise revenue without having to resort to distortionary taxes? Should decisions concerning public goods or Pigouvian taxes depend on whether their incidence is regressive? The answer...

Standard policies to correct market power and selection can be misguided when these two forces co-exist. Using a calibrated model of employer-sponsored health insurance, we show that the risk adjustment commonly used by employers to offset adverse selection often reduces the amount of...

We describe recent advances in the empirical analysis of insurance markets. This new research proposes ways to estimate individual demand for insurance and the relationship between prices and insurer costs in the presence of adverse and advantageous selection. We discuss how these models permit...

When markets are imperfectly competitive, trade policies can alter the terms of trade, shift profits from one country to another, and moderate or exacerbate existing distortions that are associated with the presence of monopoly power. In light of the various ways in which trade policies may...

Policymakers subsidizing health insurance often face uncertainty about future market prices. We study the implications of one policy response: linking subsidies to prices, to target a given post-subsidy premium. We show that these price-linked subsidies weaken competition, raising prices for the...