We apply the analytical framework of discrete structural alternatives – market, hybrid forms and hierarchy – to the choice of environmental policy instruments. Environmental-related transactions, which differ in their attributes, are aligned with categories of policy instruments, which differ in their cost and competence, so as to effect a discriminating – mainly transaction costs economizing – result. First, we suggest defining the transaction as the trading of property rights to the use of natural resources. Second, the characteristics of the transaction are described as mainly measurement costs. Third, we determine the conditions under which a particular ‘governance structure’ that is a policy instrument is chosen. A major contribution of our analysis is to question the relevance of many economists’ prescription in favour of incentive-based instruments. Indeed, in some plausible circumstances a command-and-control instrument may be more efficient by economizing on transaction costs. Environmental economics has employed the seminal contribution of Ronald H. Coase (1960) intensively but has remained relatively unaffected by the contributions of perhaps his most influential follower, Oliver E. Williamson. Our chapter is a first step towards an operationalization à la Williamson of Coase's (1992, p. 778) ‘fundamental insights’ in the environmental realm.