A Note on Emissions Taxes and Incomplete Information

In contrast with what we perceive is the conventional wisdom about setting a second-best emissions tax to control a uniformly mixed pollutant under uncertainty, we demonstrate that setting a uniform tax equal to expected marginal damage is not generally efficient under incomplete information about firms’ abatement costs and damages from pollution.

We show that efficient taxes will deviate from expected marginal damage if marginal damage is increasing and there is uncertainty about the slopes of the marginal abatement costs of regulated firms. Moreover, tax rates will vary across firms if a regulator can use observable firm-level characteristics to gain some information about how the firms’ marginal abatement costs vary.