Regulation, Asymmetric Information, and Auditing

The article analyzes a model of a regulated firm that is better informed about its cost function than is the regulator. By auditing at a cost, however, the regulator is assumed to be able to observe the realized cost of the firm. If the regulator "finds" that the firm had misrepresented its costs at the time at which prices were set, he can order a refund to consumers. In the optimal policy the regulator audits when the firm reports for pricing purposes that its costs will be high and orders a refund when the audit finds that realized costs are lower than anticipated, given the original report. A separation result that obtains for an important case indicates that the initial pricing decision is independent of the auditing decision. The auditing decision, however, depends on the price that was initially set. The optimal auditing strategy is characterized and the nature of the welfare gains are identified. The methodology used in the analysis involves the characterization of an equilibrium of a revelation game with an ex post observable.