For many products, platforms enable sellers to transact with buyers. We show that the competitive conditions among sellers shape the market structure in platform industries. If product market competition is tough, sellers avoid competitors by joining different platforms. This allows platforms to...

This paper presents a model in which a monopoly platform not only operates a marketplace intermediating direct transactions between consumers and third-party sellers, but also sells its first-party products at the marketplace, which is designated herein as platform encroachment. When...

The owners of large online platforms, like Airbnb or Amazon Marketplace, are able to affect the probability that a given buyer observes a given seller on their platform. Buyers and sellers therefore interact on a bipartite graph with links between them weighted by the probability of observation....