Sellers and Heterogeneous Bidders at Auctions: Non Cooperative and Collusive Strategic Behavior

现有的大多数拍卖研究都是在非合作框架下进行的，风险中立的竞标者都是同质的，风险中立的竞标者可以宣布保留价格。该项目的贡献来自于在异质投标人和投标人串通的相对未开发领域的工作。这项研究的动机是在拍卖中观察到的行为，如嵌套买家环的形成，不包括环和抬升内衬（幻影竞拍）的拍卖商。之前的工作通过英国拍卖的实践解释了幻影出价的产生和竞标者串通的持久性。需要进一步的研究将这些结果推广到更复杂和现实的环境中，并研究拍卖的其他方面。研究人员过去的高质量研究表明他们有能力做这项工作。该项目调查了在第一价、荷兰价和第二价拍卖中异质投标人和拍卖人的行为。关于投标人的分布信息通常不为卖方所知，因此贝叶斯拍卖师对投标数据的处理及其相应的策略行为进行了探讨。该项目解释了为什么只有包罗万象的竞标者联盟在首价和荷兰拍卖中才可行，以及为什么在英国拍卖中可以观察到各种规模的联盟。该项目调查某些类型的投标人是否不希望或不愿意加入英国拍卖的联盟。最后，该项目解释了投标人联盟如何试图避免因分享联盟形成的收益而产生的激励问题。同时博弈模型和顺序博弈模型都用于研究竞标者联盟的嵌套和其他有效分享收益的方法。

Most of the existing research on auctions has been conducted within a non-cooperative framework with homogeneous risk neutral bidders where the risk neutral auctioneer can announce a reserve price. The contribution of this project comes from working in the relatively unexplored areas of heterogeneous bidders and bidder collusion. This research is motivated by observed behavior at auctions such as nested buyer ring formation, non-inclusive rings and lift-lining (phantom bidding) by auctioneers. The previous work explained the generation of phantom bids by practicing English auctions and the durability of bidder collusion. Further research is needed to generalize these results to more complex and realistic environments and to study other aspects of auctions. The high quality of the investigators' past research shows that they have the ability to do the work. The project investigates the behavior of heterogeneous bidders and the auctioneer at first price, Dutch, and second price auctions. Distributional information regarding bidders is usually unknown by the seller, so the processing of bid data by a Bayesian auctioneer and consequent strategic behavior are explored. The project explains why only all inclusive bidder coalitions are viable at first price and Dutch auctions and why coalitions of all sizes are observed at English auctions. The project investigates if certain bidder types are either undesirable to, or, unwilling to join a coalition in an English auction. Finally, the project explains how bidder coalitions try to avoid the incentive problems created by sharing the gains of coalition formation. Both simultaneous and sequential game models are used to study nesting of bidder coalitions and other ways of efficiently sharing the gains.