タイトル:A Choice of Auction Format in Seller Cheating: A Signaling Game Analysis
概要:In this paper, we examine which of the two important auction formats, first-price or second-price auction, a seller will choose when cheating is possible, that is, the seller can observe all bids by possible buyers and submit a shill bid as pretending to be a buyer in a second price auction, and the valuations of buyers are interdependent. We model this choice of auction format in seller cheating as a signaling game in which the buyers may regard the selection of a second price auction by the seller as a signal that he is a shill bidder. By introducing trembling-hand perfectness as a refinement of signaling equilibrium, we find two possible strictly perfect signaling equilibria. One is a separating equilibrium in which a non-cheating honest seller selects a first price auction and a cheating seller does a second price auction. In another pooling equilibrium, however, both cheating and non-cheating sellers select a second price auction. The conclusion that second price auctions may be used even if the seller does not cheat is in contrast to the previous literature, which focused on the case of independent values.