Regulation of Stock Externalities with Correlated Abatement Costs

We study a dynamic regulation model where firms’ actions contribute to a stock externality. The regulator and firms have asymmetric information about serially correlated abatement costs. With price-based policies such as taxes, or if firms trade quotas efficiently, the regulator learns about the evolution of both the stock and costs. This ability to learn about costs is important in determining the ranking of taxes and quotas, and in determining the value of a feedback rather than an open-loop policy. For a range of parameter values commonly used in global warming studies, taxes dominate quotas, regardless of whether the regulator uses an open-loop or a feedback policy, and regardless of the extent of cost correlation.Early versions of this paper were presented at the Fifth California Workshop on Environmental and Resource Economics, University of California, Santa Barbara, CA, May 5–6, 2000, and at the annual meeting of the Canadian Agricultural Economics Society, University of British Columbia, Vancouver, BC, Canada, June 1–3, 2000. We thank these conference participants, and two anonymous referees of this journal for their comments, without implicating them in any remaining errors. The opinions expressed in this paper do not necessarily reflect the views of the Asian Development Bank.