Abstract： The effect of group buying strategies in different sales channels on optimal supply chain decision was analyzed under two decisionmaking approaches in a dualchannel supply chain where the manufacturer sells goods to the ultimate consumers through traditional retail channel as well as direct online channel. The research shows that under centralized system, initiating group buying through the channel with larger market share will benefit the whole supply chain, while under decentralized system, in contrast, initiating group buying through the direct online channel has the same effect on the whole supply chain. However, the retail channel will decrease not only the optimal scale of group buying but also the increment of the overall benefit of the supply chain. Finally, a numerical analysis was given to testify the conclusion.
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