This paper investigates how the tying of complementary products can be used to preserve and extend monopoly positions …. We first show how a firm that is a monopolist of a product in the current period can use tying to preserve its monopoly … monopoly position into a newly emerging market. The analysis focuses on the importance of entry costs and network externalities …

absolute margin. We derive these results in both a monopoly model and a variety of different competitive models. We conclude …

, because they intensify price competition too much. Multi-product monopoly can lead to better design incentives than the non …

price equilibrium can emerge. The paper shows that this outcome can be socially optimal and that, while a move from monopoly …