This technical note develops a complementary cooperative solution to the dynamic network game of the Fintech industry of Yeung et al. (J Oper Res Soc China. 12: 5–33, 2024). The solution satisfies the properties of individual rationality, group optimality, time consistency, and the fair gain-sharing principle. It entails two advantageous attributes over those of the Shapley value, including a gain-sharing principle based on the contributions of firms and a much simpler solution mechanism.