We model an international union as a group of countries deciding together the provision of certain public goods and policies because of spillovers. The countries are heterogeneous either in preferences and/or in economic fundamentals. The trade off between the benefits of coordination and the...

We study platforms competing in commissions on revenues of sellers engaged in monopolistic competition, as the app providers on the app stores of iPhones and Android devices. Free entry of sellers on each platform generates multihoming superstars and a long tail of singlehoming sellers....