Study on group buying auction

With the development of electronic commerce, online auction plays an important role in the electronic market. The group-buying auction (GBA) is a new kind of dynamic pricing mechanism on the Internet. It makes the bidders as a group through Internet to get the volume discounts, i.e., the more bidders bid, the lower the price of the object being auctioned becomes. In this talk, we first analyze the group-buying auction under some assumptions such as that IPVs (Independent Private Values) model applies and bidders are risk neutral and symmetric, etc., and build an incomplete information dynamic game model to illustrate the bidderspsila bidding process. It proves that for the bidders there exists a weakly dominant strategy S, i.e., no matter when a bidder arrives at the auction and what the bidding history is, the highest permitted bid price that is no greater than his value to the object is always his optimal bid price, but may not be the unique one.