Ratifiability of efficient collusive mechanisms in second-price auctions with participation costs

We investigate whether efficient collusive bidding mechanisms are affected by potential information leakage from bidders' decisions to participate in them within the independent private values setting. We apply the concept of ratifiability introduced by Cramton and Palfrey [Cramton, P.C., Palfrey, T.R., 1995, Ratifiable mechanisms: Learning from disagreement, Games Econ. Behav. 10 (2), 255–283] and show that when the seller uses a second-price auction with participation costs, the standard efficient cartel mechanisms such as pre-auction knockouts analyzed in the literature will not be ratified by cartel members. A high-value bidder benefits from vetoing the cartel mechanism since doing so sends a credible signal that she has high value, which in turn discourages other bidders from participating in the seller's auction.     

Vickrey auctions with reserve pricing

Summary. We generalize the Vickrey auction to allow for reserve pricing in a multi-unit auction with interdependent values. In the Vickrey auction with reserve pricing, the seller determines the quantity to be made available as a function of the bidders' reports of private information, and then efficiently allocates this quantity among the bidders. Truthful bidding is a dominant strategy with private values and an ex post equilibrium with interdependent values. If the auction is followed by resale, then truthful bidding remains an equilibrium in the auction-plus-resale game. In settings with perfect resale, the Vickrey auction with reserve pricing maximizes seller revenues.Received: 31 December 2002, Revised: 5 May 2003, JEL Classification Numbers: D44, C78, D82.Correspondence to: Lawrence M. AusubelThe authors gratefully acknowledge the generous support of National Science Foundation Grants SES-97-31025, SES-01-12906 and IIS-02-05489. We appreciate valuable comments from Ilya Segal. Special thanks go to Mordecai Kurz, who served as Larry's dissertation advisor and who introduced both authors to the economics profession back at IMSSS at Stanford. Congratulations and best wishes are extended to Mordecai and his family on the happy occasion of the publication of Assets, Beliefs, and Equilibria in Economic Dynamics: Essays in Honor of Mordecai Kurz, in which this article also appears.     

Computationally-feasible truthful auctions for convex bundles

In many economic settings, like spectrum and real-estate auctions, geometric figures on the plane are for sale. Each bidder bids for his desired figure, and the auctioneer has to choose a set of disjoint figures that maximizes the social welfare. In this work, we design mechanisms that are both incentive compatible and computationally feasible for these environments. Since the underlying algorithmic problem is computationally hard, these mechanisms cannot always achieve the optimal welfare; Nevertheless, they do guarantee a fraction of the optimal solution. We differentiate between two information models—when both the desired figures and their values are unknown to the auctioneer or when only the agents' values are private data. We guarantee different fractions of the optimal welfare for each information model and for different families of figures (e.g., arbitrary convex figures or axis-aligned rectangles). We suggest using a measure on the geometric diversity of the figures for expressing the quality of the approximations that our mechanisms provide.     

Revealing information in auctions: the allocation effect

When there are two bidders, releasing independent information in an English auction with private values makes the seller worse off. However, this is no longer true with more bidders: when there is enough competition, revelation benefits the auctioneer. In three examples the dividing case is shown to be three bidders. This allocation effect applies to other standard auctions and parallels the bundling decision in a multi-unit auction. I would like to thank Jeremy Bulow, Willie Fuchs, Paul Klemperer, Rob McMillan, Phil Reny, Jeff Zwiebel and especially Andy Skrzypacz. I also grateful to two referees and an Associate Editor for a number of helpful comments.     

Collusion in one-shot second-price auctions

Summary. Most of the literature on collusive behavior in auctions ignores two important issues that make collusion difficult to sustain at least in one-shot interactions: the detection of cheating and the verification of bids. Colluding bidders may deceive each other by using shill bidders. Also, if the identities of the bidders and their bids are not published then it would be difficult to verify the bid of a colluding bidder. This paper addresses these problems in one shot second price auctions where one bidder offers another bidder a side payment in exchange for not participating in the auction, while the number of other bidders is stochastic. In spite of the barriers to collusion mentioned above, a simple side payment mechanism which depends only on the auction price is introduced. It induces a successful collusion, eliminates the verification problem, provides no incentive for the use of shill bidders and guarantees that the proponent obtains ex-post non-negative payoff. The colluding bidders are ex-ante strictly better off compared with the competitive case, irrespective of their types.Received: 27 November 2002, Revised: 28 January 2005, JEL Classification Numbers: C72, D44, D82.Yair Tauman: Correspondence toWe would like to thank an anonymous referee for very valuable comments and suggestions that significantly improved the paper. We thank Shmuel Zamir for a helpful discussion.     

A short proof of the Bulow-Klemperer auctions vs. negotiations result

Summary. Bulow and Klemperer [1] have provided an upper bound on the value of bargaining power for a seller of an indivisible object. Specifically, negotiating optimally with N buyers yields lower revenue than an English auction with N + 1 buyers. In this paper, a short and intuitive proof of this result is presented.Received: 2 August 2004, Revised: 6 December 2004, JEL Classification Numbers: C78, D44, D82.I would like to thank Per B. Overgaard and an anonymous referee for many valuable comments.     

Mental processes and strategic equilibration: An fMRI study of selling strategies in second price auctions

This study is the first to attempt to isolate a relationship between cognitive activity and equilibration to a Nash Equilibrium. Subjects, while undergoing fMRI scans of brain activity, participated in second price auctions against a single competitor following predetermined strategy that was unknown to the subject. For this auction there is a unique strategy that will maximize the subjects’ earnings, which is also a Nash equilibrium of the associated game theoretic model of the auction. As is the case with all games, the bidding strategies of subjects participating in second price auctions most often do not reflect the equilibrium bidding strategy at first but with experience, typically exhibit a process of equilibration, or convergence toward the equilibrium. This research is focused on the process of convergence.In the data reported here subjects participated in sixteen auctions, after which all subjects were told the strategy that will maximize their revenues, the theoretical equilibrium. Following that announcement, sixteen more auctions were performed. The question posed by the research concerns the mental activity that might accompany equilibration as it is observed in the bidding behavior. Does brain activation differ between being equilibrated and non-equilibrated in the sense of a bidding strategy? If so, are their differences in the location of activation during and after equilibration? We found significant activation in the frontal pole especially in Brodmann’s area 10, the anterior cingulate cortex, the amygdala and the basal forebrain. There was significantly more activation in the basal forebrain and the anterior cingulate cortex during the first sixteen auctions than in the second sixteen. The activity in the amygdala shifted from the right side to the left after the solution was given.     

Information acquisition in auctions: Sealed bids vs. open bids

This paper studies the incentives of a bidder to acquire information in an auction when her information acquisition decision is observed by the other bidders before bidding. Our results show that the sealed bid (second price) auction may induce more information acquisition about a common component of the value than the open (English) auction but less about the private component of the value. Moreover, we show that more information about the private value and less information about the common value may improve efficiency and revenue. Consequently, our results suggest new arguments in favor of the open auction.     

Finding and retaining the dominant strategy: The second-price, English and ‘sealed offer’ English auctions

Using experiments in a procurement setting, this study examined the performance abilities of three auctions: the second-price, English, and a new ‘sealed offer’ English. Additionally, to see if dominant strategy learning would be transferred, after fifteen periods with one of the three auctions, all subjects completed a second 15 periods with the second-price auction. The English auction performed best overall. However, only limited learning was found to occur, with some subjects that had adopted the dominant strategy in the English switching in the second-price. Lessons from the new mechanism transferred better, but initial learning of the dominant strategy was slower.     

Regret in auctions: theory and evidence

The sealed-bid first-price auction of a single object in the case of independent privately-known values is the simplest auction setting and understanding it is important for understanding more complex mechanisms. But bidders bid above the risk-neutral Nash equilibrium theory prediction. The reasons for this “over bidding” remain an unsolved puzzle. Several explanations have been offered, including risk aversion, social comparisons, and learning. We present a new explanation based on regret and a model that explains not only the observed over bidding in sealed-bid first-price auctions, but also behavior in several other settings that is inconsistent with risk aversion. The authors gratefully acknowledge support from the National Science Foundation.     

The law of small numbers: investigating the benefits of restricted auctions for public procurement

A commonly accepted view in the academic literature is that dispensing with competition may only be beneficial when tendering complex contracts. However, restricted auctions are frequently used among EU member states to procure small contracts. In this article, we investigate this paradox. Using an original data set of 180 contracts used by a local public buyer of social housing between 2006 and 2009, we show that limiting competition may enable economies to be made on transaction costs while the most efficient bidders still come forward, and that abuses such as corruption or favouritism do not result. To our knowledge, this article is the first to shed light on the advantages of using restricted auctions when tendering small simple contracts.     

License auctions with royalty contracts for (winners and) losers

This paper revisits the licensing of a non-drastic process innovation by an outside innovator to a Cournot oligopoly. We propose a new mechanism that combines a restrictive license auction with royalty licensing. This mechanism is more profitable than standard license auctions, auctioning royalty contracts, fixed-fee licensing, pure royalty licensing, and two-part tariffs. The key features are that royalty contracts are auctioned and that losers of the auction are granted the option to sign a royalty contract. Remarkably, combining royalties for winners and losers of the auction makes the integer constraint concerning the number of licenses irrelevant.     

Sequencing strategies in large, competitive, ascending price automobile auctions: An experimental examination

This paper reports on a large-scale field experiment testing strategies available to a seller participating in simultaneous competitive sequential ascending price automobile auctions. Every other week, the seller offered approximately 100 vehicles for sale in an auction environment in which several competing sellers offered on the order of 3000 vehicles. The experiment tested various sequences in which the seller could offer the vehicles, such as high values first or low values first. Surprisingly, and contrary to intuition drawn from the theory of single item and single seller auctions, the worst performing sequence from those tested is for the seller to order vehicles from highest to lowest values. The best sequence is to group the vehicles by type and offer the low valued vehicles first and then move to offer the higher valued vehicles.     

First-price auctions with resale: the case of many bidders

We study first-price auctions with resale when there are many bidders and derive existence and characterization results under the assumption that the winner of the initial auction runs a second-price auction with an optimal reserve price. The fact that symmetrization fails when there are more than two bidders has been observed before, but we also provide the direction: weaker bidders are less likely to win than stronger ones. For a special class of distributions and three bidders, we prove that the bid distributions are more symmetric with resale than without. Numerical simulations suggest that the more bidders there are, the more similar the allocation is to the case without resale, and thus, the more asymmetric the bid distributions are between strong and weak bidders. We also show in an example that the revenue advantage of first-price auctions over second-price auctions is positive, but decreasing in the number of bidders.     

互联网革命下的贸易创新研究

互联网的发展与广泛应用给各行各业带来了深远的影响 ,流通领域也不例外。互联网为买卖双方直接沟通产销信息提供了最廉价的工具 ,也成为企业之间进行信息交换和资源共享的最佳方式。本文主要探讨网络化和全球化的背景下 ,传统贸易在组织形式、流通模式、流通渠道以及营销方式等方面的创新。     

Market manipulation with sentiment traders

This article offers a new perspective for traders’ sentiment by bridging the relationship between feedback effect and market manipulation. Allowing access to information regarding manipulated orders confuses sentiment traders, leading to an overestimation of the true asset value which actually remains the same. We find that sentiment factor has a nonmonotonic impact on the responsiveness to order information and price informativeness. Furthermore, it is shown that informed traders behave like a contrarian, and can use order information to reassess the price, which results in the multiplicity of equilibria.     

Bilateral trade with apositional traders

We study the standard model of bilateral trade under incomplete information dropping the assumption that traders know on which side of the market they are. We consider two mechanisms that differ only in the number of offers that an agent can submit. These mechanisms are realistic and they are ex post individually rational (i.e. regret free), while the usual mechanisms proposed in the literature satisfy the weaker requirement of interim individual rationality. Properties of the Bayesian equilibria are described for the general case. For the case where valuations are uniformly distributed in the unit square, two types of equilibria are derived for each mechanism and their efficiency properties are analyzed. As expected, the equilibria under the double offer mechanism are less inefficient than those under the single offer mechanism.     

Economic crisis and benefits of the Internet: differentiated Internet usage by employment status

Using data from the Spanish Survey on Equipment and Use of ICTs in Households for 2007–2011, this paper evaluates the effect of employment status on the diffusion of the Internet among the labor force. We use a bivariate probit with sample selection model to account for a potential selection bias that arises because online usage is only observed for Internet users. Our results show that, controlling for income, employment influences online adoption and usage, and we find evidence of a digital divide in adoption and usage by education and age among the labor force. Employed individuals are more likely to have accessed the Internet and used it more frequently than the unemployed and for different activities. However, conditional on adoption, they do not use the Internet for more personal activities. These findings suggest that firms promote and subsidize Internet access, but this sponsored access does not translate into more personal use.     

Internet cautions: Experimental games with internet partners

We report the results of experiments conducted over the internet between two different laboratories. Each subject at one site is matched with a subject at another site in a trust game experiment. We investigate whether subjects believe they are really matched with another person, and suggest a methodology for ensuring that subjects’ beliefs are accurate. Results show that skepticism can lead to misleading results. If subjects do not believe they are matched with a real person, they trust too much: i.e., they trust the experimenter rather than their partner. JEL Classification C9