An increasing number of planners have explored the implication of Coase theorem for planning theory and practice. As there are often a large and dispersed number of actors involved in planning issues, the application of ‘Pure’ Coasian solutions has proved to be limited. However, some studies argue that when the conditions for a ‘Pure’ Coasian solution do not exist, ‘Impure’ Coasian solutions may still be achievable. This article examines how, when conditions of ‘Impure’ Coasian solutions are available, local authorities in Switzerland use land improvement syndicates as a policy instrument in order to achieve negotiated solutions in relation to development processes involving multiple landowners. With a syndicate in the commune of Cheseaux as an illustrative example, the article analyses how this policy instrument has been utilised to reduce transaction costs, correct information asymmetries and clarify property rights. The focus has been on an interpretation of the Coasian theorem that identifies attempts to reduce transaction costs and clarify property rights as the main roles of governments or local authorities.