We explore the efficacy of price and quantity controls as environmental policy instruments in a stochastic setting in which agents are risk averse. We demonstrate that the assumption of risk aversion may improve the performance of a tax relative to that of a system of tradable quotas, and that restricting quota trade may enhance e.ciency even though risk aversion in itself limits volumes of trade. The government may be able to improve the performance of a tradable quota system by judicious choice of distribution and amount of initial quotas and by trading pro-actively in the quota market
