Collusion through communication in auctions

We study the extent to which communication can serve as a collusion device in one-shot first- and second-price sealed-bid auctions. In an array of laboratory experiments we vary the amount of interactions (communication and/or transfers without commitment) available to bidders. We find that communication alone leads to statistically significant but limited price drops. When, in addition, bidders can exchange transfers, revenues decline substantially, with over 70% of our experimental auctions culminating in the object being sold for approximately the minimal price. Furthermore, the effects of communication and transfers are similar across auction formats. We contrast these results with those generated in repeated auctions. By and large, repeated auctions yield lower collusion and lower efficiency levels

Collusion through Communication in Auctions

We study the extent to which communication can serve as a collusion device in one-shot first- and second-price sealed-bid auctions. Theoretically, second-price auctions are more fragile to collusion through communication than first-price auctions. In an array of laboratory experiments we vary the amount of interactions (communication and/or transfers without commitment) available to bidders. We find that the auctioneer's revenues decrease significantly when bidders can communicate. When, in addition, bidders can make transfer promises, revenues decline substantially, with 70% of our experimental auctions culminating in the object being sold for approximately the minimal price. Furthermore, the effects of communication and transfers are similar across auction formats

Collusion through communication in auctions

We study the extent to which communication can serve as a collusion device in one-shot first- and second-price sealed-bid auctions. In an array of laboratory experiments we vary the amount of interactions (communication and/or transfers without commitment) available to bidders. We find that communication alone leads to statistically significant but limited price drops. When, in addition, bidders can exchange transfers, revenues decline substantially, with over 70% of our experimental auctions culminating in the object being sold for approximately the minimal price. Furthermore, the effects of communication and transfers are similar across auction formats. We contrast these results with those generated in repeated auctions. By and large, repeated auctions yield lower collusion and lower efficiency levels

Tacit Collusion in Repeated Auctions

We study tacit collusion in repeated auctions in which bidders can only observe pastwinners and not their bids. We adopt a stringent interpretation of tacit collusion ascollusion without communication about strategies that we model as a symmetryrestriction on repeated game strategies: Strategies cannot discriminate among initiallynameless bidders until they have become named through winning an auction. We obtainthree classes of results: (1) Completely refraining from using names, i.e. strengtheningthe symmetry constraint, rules out collusion altogether, and even if naming is permitted,as per our definition of tacit collusion, the lack of communication limits collusivestrategies and payoffs among impatient bidders. (2) If communication is allowed, thereare sustained improvements over bid rotation and competitive bidding among patientbidders. (3) These gains extend to tacit collusion among patient bidders. However,whether tacit or not, collusion need not be efficient. ZUSAMMENFASSUNG - (Stillschweigende Kollusion in wiederholten Auktionen) Der Beitrag untersucht die Möglichkeiten von "tacit collusion" (stillschweigender Kollusion) in wiederholten Auktionsspielen in welchen nur die vergangenen Gewinner nicht aber deren Gebote bekannt sind. Dabei wird "tacit collusion" als kollusives Verhalten ohne Absprachen zwischen den Bietern interpretiert. In dem Artikel werden insbesondere auch vor dem Spiel getroffene Absprachen über Strategien ausgeschlossen. Das Fehlen solcher Absprachen wird durch Symmetrierestriktionen modelliert: Strategien können solange nicht zwischen anfangs "namenlosen" Bietern unterscheiden, bis diese sich durch das Gewinnen einer Auktion von den anderen Bietern differenzieren. Es werden drei Arten von Ergebnissen hergeleitet: (1) Stärkt man die Symmetrierestriktionen und verlangt symmetrisches Verhalten in jeder Periode, so kann keine Kollusion auftreten. Aber auch weniger starke Symmetrierestriktionen, die prinzipiell eine endogene Rollenverteilung ermöglichen, schränken die möglichen Kollusionsgewinne bei ungeduldigen Bietern ein. (2) Erlaubt man vor dem Spiel getroffene Absprachen über die Strategiewahl, so können hinreichend geduldige Bieter unbegrenzt höhere Gewinne erhalten als die Gewinne bei wiederholtem Konkurrenzverhalten oder bei einer einfachen Bieterrotation. (3) Dies gilt auch für Kollusion ohne Absprachen falls die Bieter hinreichend geduldig sind. Jedoch, ob mit oder ohne a-priori Absprachen, effiziente Kollusion kann selbst bei extrem geduldigen Bietern unmöglich sein.Tacit Collusion, Auctions, Supergames, Strategic Uncertainty, Language, Attainability

Efficient Collusion in Repeated Auctions with Communication,

This paper studies collusion in repeated auctions when bidders communicate prior to each stage auction. The paper presents a folk theorem for independent and correlated private signals and general interdependent values. Specifically, it identifies conditions under which an equilibrium collusion scheme is fully efficient in the sense that the bidders' payoff is close to what they get when the object is allocated to the highest valuation bidder at the reserve price in every period.

Collusion in Auctions for Emission Permits: An Experimental Analysis

Environmental markets have several institutional features that provide a new context for the use of auctions and which have not been studied previously. This paper reports on laboratory experiments testing three auction forms -– uniform and discriminatory price sealed bid auctions and an ascending clock auction. We test the ability of subjects to tacitly or explicitly collude in order to maximize profits. Our main result is that the discriminatory and uniform price auctions produce greater revenues than the clock auction, both without and with explicit communication. The clock appears to be more subject to successful collusion because of its sequential structure and because it allows bidders to focus on one dimension of cooperation (quantity) rather than two (price and quantity).auctions, collusion, experiments, carbon dioxide, greenhouse gases

Bidding Markets

The existence of a ‘bidding market’ is commonly cited as a reason to tolerate the creation or maintenance of highly concentrated markets. We discuss three erroneous arguments to that effect: the ‘consultants’ fallacy’ that ‘market power is impossible’, the ‘academics’ fallacy’ that (often) ‘market power does not matter’, and the ‘regulators’ fallacy’ that ‘intervention against pernicious market power is unnecessary’, in markets characterized by auctions or bidding processes. Furthermore we argue that the term ‘bidding market’ as it is widely used in antitrust is unhelpful or misleading. Auctions and bidding processes do have some special features—including their price formation processes, common-values behaviour, and bid-taker power—but the significance of these features has been overemphasized, and they often imply a need for stricter rather than more lenient competition policy.Bidding Markets, Auctions, Antitrust, Competition Policy, Bidding, Market Power, Private Values, Common Values, Anti-trust

Collusion in repeated auctions: a simple dynamic mechanism

We analyze collusion in an infinitely repeated version of a standard auction with a continuum of types. Because of the lack of efficiency results in this setting the literature has focused on determining and comparing benchmarks on how well bidders can collude. Aoyagi (2003) has shown that the bidders can improve upon static bid rotation, making use of a dynamic bid rotation scheme, but this scheme does not allow to determine how much bidders can improve upon bid rotation. In this paper we design a very simple dynamic mechanism that improves upon static bid rotation and in the limit recovers one third of the gap between static bid rotation and efficiency, independently of the underlying distribution of values.Auctions, Collusion, Repeated Games, Private Information

An experimental investigation of collusion in hard-close auctions: partners and friends

We study collusion in the finitely repeated, hard-close auction experiment. Three subjects, identified by their bidder name, simultaneously compete in three auction markets. Due to the experimental design, subjects are enabled to the sharing of the benefits of cooperation by coordinating their individual demands. Similar collusive behavior has been suggested to play an important role in empirical markets (Klemperer 2002). We consider two treatments. In the first one, the partners treatment, subjects who are identified by bidder-names interact repeatedly but anonymously with each other. In the second one, the friends treatment, groups of three subjects who participate together in the experiment, interact repeatedly with another. In the experiment, we do not observe tacit collusion in the partners treatment; the outcome is efficient and prices converge quickly to the rational equilibrium prediction. Only in the friends treatment, cooperation gains can be realized, but much less cooperation is observed than one would imagine. We conclude that in the laboratory, cooperation is difficult to achieve in the hard-close auction market if anonymity prevails.multi unit auctions, collusion, experimental economics