Environmental Regulation of Firms that Experience Dynamic Inconsistency

The recent push for environmental regulation has invigorated the discussion of mechanism design and optimal taxation policy. Recent decades have also seen growing interest in behavioural economics and empirically based theory. In this thesis we take a step towards combining the two by asking how a regulator may correct an externality in situations where they have a time consistency problem. Time inconsistency is one of the notable developments of behavioural economics. It posits that an agent’s decisions do not remain consistent over time, which causes a utility loss if the agent cannot commit themselves to a particular course of action and stick to it. The solution to inconsistency problems is to precommit to a course of action and prevent future deviations from it. However, finding a mechanism to enable such precommitment is often problematic. A regulator who maximises welfare can have a time consistency problem because welfare will depend on the decisions of firm and households who may themselves be inconsistent. That inconsistency then propagates to the regulator’s decision and reduces the level of welfare that the regulator can reach. Alternatively, the regulator’s time consistency problem can be caused by non-stationarity in their time preferences. To reach the firstbest outcome the regulator must not only eliminate the environmental externality: they must also overcome their own time inconsistency problem. This thesis draws from the literature on strategic delegation to construct a taxation game in which the regulator can achieve the first best taxation regime without the need for external precommitment devices. We study a dynamic game where the regulator chooses a tax rate and the regulated monopolist chooses their price. We show that the Markov-perfect equilibrium price path of this game will replicate the first best plan. Our results holds for time inconsistency caused by both jump states and quasihyperbolic discounting.