In this paper we develop design principles for a serious game on data sharing in business ecosystems. Even though data has been said to be the new fuel of the economy, we have not seen much large-scale data trading in industrial settings. The purpose of the game is to experimentally study the dynamics of data trading in simulated business ecosystems, particularly under different kinds of governance structures: in centralized and decentralized ecosystems. The objective of the game is also to support the learning of MBA and university students. Through the game, the students can experience the risks and benefits of sharing data in ecosystems, an emerging and increasingly important topic in business life.