Implementing optimal taxes using tradable share permits

This paper presents a simple system for efficient regulation under asymmetric information. Each firm's income is controlled by a tax that depends on the firm's own output and on a parameter construed as a share permit. These “shares of total expected output” lower a firm's tax burden and are acquired in a competitive market. By employing this scheme, the planner only requires knowledge of marginal damage to induce the first-best outcome. Relative to a traditional cap-and-trade approach the system increases expected social welfare.