The externalities advertisers receive from newspaper readers and that operating system users receive from software developers are among the leading features of those “platform” industries. However, they are rarely incorporated into applied models of imperfect competition. We argue this...

We consider a software vendor first selling a monopoly platform and then an application running on this platform. He may face competition by an entrant in the applications market. The platform monopolist can benefit from competition for three reasons. First, his profits from the platform...

"Double marginalization" and "Elimination of Double marginalization" are catch-phrases commonly used in the IO literature. In this note, I trace back the origin of the idea to Chapter IX, on complementary goods monopolies, of Cournot (1838). Through the years Cournot's contribution remained a...

In the 1950s and 60s, Japanese and US antitrust authorities occassionally used the degree of concentration to regulate industries. Does regulating firms based on their market shares make theoretical sense? We set up a simple duopoly model with stochastic R&D activities to evaluate market share...

In this paper I set forth an antitrust remedy for the oligopolistic pricing problem. Oligopoly pricing resembles a repeated prisoners' dilemma game. Each firm has an incentive to moderately lower its price and thus increase its sales at its competitors' expense. However, each firm knows that its...

Motivated by the unprecedented availability of consumer information on the Internet, we characterize the winners and losers from potential privacy regulation in the context of four commonly-used oligopoly models: a linear city model, a circular city model, a vertical differentiation model, and a...

Motivated by the unprecedented availability of consumer information on the Internet, we characterize the winners and losers from potential privacy regulation in the context of four commonly-used oligopoly models: a linear city model, a circular city model, a vertical differentiation model, and a...

Cartels are inherently instable. Each cartelist is best off if it breaks the cartel, while the remaining firms remain loyal. If firms interact only once, if products are homogenous, if firms compete in price, and if marginal cost is constant, theory even predicts that strategic interaction...

The presence of multiple sellers in the provision of (non-substitutable) complementary goods leads to outcomes that are worse than those generated by an integrated monopoly, a problem also known as the «tragedy of the anticommons». In this paper we identify some conditions under which the...

Cartels are inherently instable. Each cartelist is best off if it breaks the cartel, while the remain-ing firms remain loyal. If firms interact only once, if products are homogenous, if firms compete in price, and if marginal cost is constant, theory even predicts that strategic interaction...