We develop a model that combines competitive exchange of private commodities across endogenously formed groups with public good provision and global collective decisions. There is a tension between local and global collective decisions. In particular, we show that group formation and collective...

When providing public goods through voluntary contributions, a donor may introduce unilateral matching in order to reduce underprovision of the public good and thus inefficiency. By itself, however, matching benefits the donor but harms the recipient. We apply Cornes and Hartley’s aggregative...