We consider innovation incentives in markets where final goods are systems comprising two strictly complementary components, one of which is monopolized. We focus on the case in which the complementary component is competitively supplied and innovation is important. We explore ways in which the monopoly may have incentives to extract efficiency rents in the competitive sector, thus weakening or destroying incentives for independent innovation. We discuss how these problems are affected if the monopolist integrates into supply of the complement.