Envelopment strategies and contract design of two-sided platforms
研究了双边平台在何种情况下采用纯包络、混合包络或不包络策略，并提出了部分股权、比例费用和固定费用三种合同来协调平台合作，发现部分股权合同能实现与集中决策相同的总利润。
Platform envelopment, which describes the embedding of one platform into another platform, is widely adopted by platforms with network effects. The strategic use of platform envelopment is determined by the tradeoff between the benefits of sharing existing users and inconvenience of using the embedded platform. This study investigates when the pure envelopment strategy (PES), mixed envelopment strategy (MES), or no envelopment strategy (NES) should be adopted and examines several coordination schemes for the platforms. A centralized decision-making case and a decentralized decision-making case are first formulated and compared. The results show that NES is the only equilibrium solution under a decentralized decision-making case and the cooperation between the two platforms can lead to higher profit of both platforms by adopting the PES or the MES. We then propose a partial equity ownership (PEO) contract, a proportional fee (PF) contract, and a fixed fee (FF) contract to coordinate the system, benefiting both platforms. The PES or the MES may be the equilibrium strategy under a PEO contract, whereas the MES is the only equilibrium strategy under a PF or an FF contract. This study finds that the adoption of a PEO contract will lead to higher surplus of consumers and providers, and social welfare. In addition, we find that only PEO contract may perfectly coordinate platforms to achieve the same total profit as that under the centralized decision-making case, while PF and FF contracts cannot.