The assignment of property rights has important implications for both economic efficiency and the distribution of surplus within society. Consequently, there are trade-offs associated with the design of these rights. Awarding a full property right over an economic resource incentivizes the owner to make efficient investment decisions related to its use. However, when transaction costs are present, strong property rights may inhibit the future reallocation of economic resources to agents who can utilize them most efficiently. Moreover, the assignment of property rights may give rise to market power or conflict with society's distributive objectives. This raises a natural question: How should property rights be optimally designed?

Online platforms increasingly act as gatekeepers that enable producers to access downstream markets, while also competing with producers in these downstream markets. A prominent example is Amazon, which sells e-commerce and distribution services to producers in an upstream market, while also selling AmazonBasics and other private-label products downstream. Should platforms be allowed to control whom they compete with in downstream markets through their upstream market interactions?