We develop a framework for specifying and reasoning about policies for sharing resources in coalitions, focussing here on a particular, common type of contract in which coalition members agree to make available some total amount of specified resource over a given time period. The main part of the framework is a policy language with two basic elements: 'obligations' (of a member enterprise to provide a total amount of resource over a given time period) express the coalition policy, and 'entitlements' (granted by an enterprise to other coalition members) express the local policies of the coalition members. We discuss the conditions under which a local policy can be said to be in compliance with, or meet, the obligations of a coalition policy, and the conditions under which an obligation, and by extension a contract, can be said to be violated or fulfilled.