This article investigates how the tying of complementary products can be used to preserve and create monopoly positions. We first show how a monopolist of a product in the current period can use tying to preserve its monopoly in the future. We then show how a monopolist in one market can employ...

In 1991, the U.S. Justice Department's Antitrust Division accused MIT and the Ivy League schools of fixing prices. The schools claimed that their cooperative behavior enabled them to concentrate financial aid on needy students and did not affect price. We analyze the empirical determinants of...