I develop a framework to explain why identity divides some communities and not others. An identity group is defined as a group of individuals with the same `culture'. A community is divided when different identities are socially segregated; a community is integrated when there is no social...

We discuss the current structure of card networks that facilitate transactions between merchants and consumers. We find that presently fees for this intermediation are considerably higher than costs. This is facilitated by rules imposed by the card networks on the merchants that do not allow...

This paper examines the preferences of a foreign firm and a welfare-maximizing host country government over two modes of foreign direct investment (FDI): de novo entry by the foreign firm and acquisition of the domestic incumbent. Two crucial features of the model are the presence of network...

The Microsoft cases in the United States and in Europe have been influential in determining the contours of the substantive liability standards for dominant firms in US antitrust law and in EC Competition law. The competition law remedies that were adopted, following the finding of liability,...

I examine interconnection decisions of differentiated firms. I find that previous results that firms never interconnect enough do not hold. In a Hotelling model consumers may suffer from interconnection, and firms may interconnect when it is not socially optimal. The firms interconnect too much...

We discuss and compare the remedies in the two cases antitrust cases of the European Union (EU) against Microsoft. The first EU case alleged (i) that Microsoft illegally bundled the Windows Media Player (WMP) with Windows; and (ii) that Microsoft did not provide adequate documentation that would...

We study duopoly pricing in the market for mobile phone service, which features network externalities, switching costs, and consumer heterogeneity. We introduce a steady state approach that enables a tractable analysis without endgame effects. The model can generate a variety of testable...

This paper examines the justifications, history, and practice of regulation in the US telecommunications sector. We examine the impact of technological and regulatory change on market structure and business strategy. Among others, we discuss the emergence and decline of the telecom bubble, the...