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...

We consider a general equilibrium model where groups operating in a competitive market environment can have several members and make efficient collective consumption decisions. Individuals have the option to leave the group and make it on their own or join another group. We study the effect of...