Optimal Cartel Prices in Two-Sided Markets

We study optimal cartel prices in a two-sided market. We present a simple model showing that prices above the two-sided monopoly price may prevail on one side of a two-sided market as a means to enhance the sustainability of the cartel. We prove that in such a case a higher benefit from the network effect may compensate customers on that side of the market for the higher prices they are charged. We then provide both sufficient and necessary conditions for these results to hold in more complex models of two-sided markets. Our analysis extends to cartels in two-sided markets a result previously known for cartels selling complementary products, despite the fact that products in a two-sided market are not complements for customers, since customers typically buy only one of the two products (e.g. in the case of newspapers, advertisers buy advertising slots while readers buy content) and products on each side are substitutes (e.g. newspapers publishers compete for readers and for advertisers).