Fixed Fee or Proportional Fee? Contracts in Platform Selling Under Asymmetric Information

Jun Wang, Qian Zhang, and Pengwen Hou
International Journal of Electronic Commerce,
Volume 26, Number 2, 2022, pp. 245-275.


In platform selling, platforms commonly charge third-party sellers a commission fee, which affects sellers’ decision making and platforms’ contract choice. This study explores this choice where a platform privately knows the market size and intends to signal to a seller. We aim to provide researchers and platform-selling practitioners insights into contract and information strategies. The result shows that the fixed-fee contract leads to either a costly or a costless signaling scenario. In costly scenarios, the high-demand platform must downward distort the fixed rent to distinguish itself from the low-demand platform. This distortion results in a different consensus on two players’ contract preference when the commission rate in the proportional-fee contract is exogenous. Under symmetric information, consensus is achieved only on the proportional-fee contract. However, in asymmetric information settings, this consensus may arise on fixed-fee contracts if market uncertainty is high. Furthermore, the comparison of information strategies reveals that players can reach an agreement on both the information-sharing strategy and the proportional-fee contract under certain conditions. When the platform endogenously determines the commission rate, this decision making can also signal demand type, and only the proportional-fee contract leads to a win–win outcome.