Simultaneous use of auctions and posted prices

I consider a model in which several identical objects are sold simultaneously via an auction and a posted price mechanism. The model explains several empirical regularities regarding bidding behavior in eBay auctions such as the finding that some bidders bid multiple times over the course of the auction, and that bidders tend to bid with greater frequency near the end of the auction than the beginning. I also show that sellers prefer to simultaneously use auctions and posted prices than to use either mechanism individually.     

REPUTATIONAL BIDDING

We consider auctions where bidders care about the reputational effects of their bidding and argue that the amount of information disclosed at the end of the auction will influence bidding. We focus on bid disclosure rules that capture all of the realistic cases. We show that bidders distort their bidding in a way that conforms to stylized facts about takeovers/licence auctions. We rank the disclosure rules in terms of their expected revenues and find that, under certain conditions, full disclosure will not be optimal. First‐price and second‐price auctions with price disclosure are not revenue equivalent and we rank them.     

An Insiders' View of FCC Spectrum Auctions

After a long period of awarding spectrum licenses inefficiently, changes in the budget and budgetary process coupled with increases in the value of the spectrum for non-broadcast use led Congress to allow the Federal Communications Commission to award licenses through competitive bidding. Contrary to the perceived view of government bureaucracies as excessively cautious, the FCC used the newfound authority to adopt a novel approach to auction design—simultaneous multiple round auctions. The innovative auction design would not have been adopted without the successful collaboration between government economists and academic economists, who helped to formulate and refine the design so that decision makers at the FCC could be convinced that the novel technique was both superior and practical. The FCCs implementation of competitive bidding was not only rapid as mandated by Congress, but also much less costly than outside alternatives and allowed the integration of spectrum policy decisions and auction design. Experience from several auctions has led to a number of open questions and refinements. The FCC is trying to replicate the success with the original auction design by facilitating dialog between the agency and outside auction experts in order to address these issues.     

eBay’s proxy bidding: A license to shill

We introduce a bidding strategy which allows the seller to extract the full surplus of the high bidder in eBay auctions. We call this a “Discover-and-Stop” bidding strategy and estimate that 1.39 percent of all bids in eBay auctions are placed by sellers (or accomplices) who execute this strategy. We argue that this kind of shill bidding is unnecessarily effective due to eBay’s proxy system and the predictability of other bidders’ bids. We also model eBay auctions with shill bidding and find that, in equilibrium, eBay’s profits are higher with shilling than without it. Finally, to determine whether bidders have an incentive to bid on their own items, we mimic the bidding behavior of shill bidders in actual eBay auctions and find some evidence of the strategy’s success.     

Strategic Jump Bidding in English Auctions

This paper solves for equilibria of sequential bid (or English) auctions with affiliated values when jump bidding strategies may be employed to intimidate one's opponents. In these equilibria, jump bids serve as correlating devices which select asymmetric bidding functions to be played subsequently. Each possibility of jump bidding provides a Pareto improvement for the bidders from the symmetric equilibrium of a sealed bid, second-price auction. The expanded set of equilibria can approximate either first- or second-price outcomes and produce exactly the set of expected prices between those two bounds. These results contrast with standard conclusions that equate English and second-price auctions.     

Multi-unit auctions with private information: an indivisible unit continuous price model

We construct a model of multi-unit auctions in which I bidders bid for two indivisible units of a common value good. Using a first-order approach, we find that there are equilibria in which bidders bid the same price for both units in the discriminatory auction, but not in the uniform auction. When there are only two bidders, under certain conditions, there are linear equilibria for both the discriminatory and the uniform auction formats. In all equilibria, bidders equalize the expected marginal benefit of bidding to the marginal costs of bidding. We show that comparison of the seller??s expected revenue across auction formats depends only on the ratio of the precision of private information to the precision of public information.     

Behavior in second-price auctions by highly experienced eBay buyers and sellers

We report on sealed-bid second-price auctions that we conducted on the Internet using subjects with substantial prior experience: they were highly experienced participants in eBay auctions. Unlike the novice bidders in previous (laboratory) experiments, the experienced bidders exhibited no greater tendency to overbid than to underbid. However, even subjects with substantial prior experience tended not to bid their values, suggesting that the non-optimal bidding of novice subjects is robust to substantial experience in non-experimental auctions. We found that auction revenue was not significantly different from the expected revenue the auction would generate if bidders bid their values. Auction efficiency, as measured by the percentage of surplus captured, was substantially lower in our SPAs than in previous laboratory experiments.     

Market composition and experience in common-value auctions

This study investigates whether market composition affects individual bidding and the aggregate market in first-price sealed-bid common-value auctions. It compares all-inexperienced markets with only inexperienced bidders, all-experienced markets with only experienced bidders, and mixed markets with both types. On average, there is no market-composition effect for both experienced and inexperienced bidders. When controlling for gender, a market-composition effect appears for inexperienced subjects: Men bid more aggressively in mixed than in all-inexperienced markets, and women bid more aggressively in all-inexperienced markets. On the aggregate level, the all-inexperienced market is the most aggressive with highest winning bids; the all-experienced market is the least aggressive. The mixed market is in between: Both experienced and inexperienced win auctions in this market, but experienced bidders win less auctions than they should.     

Empirical Implications of Equilibrium Bidding in First-Price, Symmetric, Common Value Auctions

This paper studies federal auctions for wildcat leases on the Outer Continental Shelf from 1954 to 1970. These are leases where bidders privately acquire (at some cost) noisy, but equally informative, signals about the amount of oil and gas that may be present. We develop tests of rational and equilibrium bidding in a common values model that are implemented using data on bids and ex post values. We also use data on tract location and ex post values to test the comparative static prediction that bidders may bid less aggressively in common value auctions when they expect more competition. We find that bidders are aware of the "winner's curse" and their bidding is largely consistent with equilibrium.     

Learning to bid: The design of auctions under uncertainty and adaptation

We examine auction design in a context where symmetrically informed adaptive agents with common valuations learn to bid for a good. Despite the absence of private valuations, asymmetric information, or risk aversion, bidder strategies do not converge to the Bertrand–Nash equilibrium strategies even in the long run. Deviations from equilibrium strategies depend on uncertainty regarding the value of the good, auction structure, the agents? learning model, and the number of bidders. Although individual agents learn Nash bidding strategies in isolation, the learning of each agent, by flattening the best-reply correspondence of other agents, blocks common learning. These negative externalities are more severe in second-price auctions, auctions with many bidders, and auctions where the good has an uncertain value ex post.     

Bidding for the future: signaling in auctions with an aftermarket

This paper considers auctions where bidders compete for an advantage in future strategic interactions. When bidders wish to exaggerate their private information, equilibrium bidding functions are biased upwards as bidders attempt to signal via the winning bid. Signaling is most prominent in second-price auctions where equilibrium bids are “above value.” In English and first-price auctions, signaling is less extreme since the winner incurs the cost of her signaling choice. The opportunity to signal lowers bidders’ payoffs and raises revenue. When bidders understate their private information, separating equilibria need not exist and the auction may not be efficient.     

Testing the continuity of individual bid density functions: Some further results

This brief paper analyzes the bidding behavior in OCS oil auctions of six individual bidders (using solo bids only) and of a consortium bidder over the period 1963–1979. Included are bidders that bid over the entire period, one that bids for only a short time at the beginning, and one that first makes such bids in 1970. Our findings strongly support those reported in an earlier paper for five bidders and a brief, three-auction sample period: bidders commonly utilize multiple bids of single dollar values within a given auction. The strength of the present results – for three of the seven bidders, over 30% of the bids made fell into this category – further buttresses our conjecture that the use of continuous bid functions is inappropriate for modelling offshore oil lease auctions.     

Bidding behavior in competing auctions: Evidence from eBay

Much of the existing auction literature treats auctions as running independently of one another, with each bidder choosing to participate in only one auction. However, in many online auctions, a number of substitutable goods are auctioned concurrently and bidders can bid on several auctions at the same time. Recent theoretical research shows how bidders can gain from the existence of competing auctions, the current paper providing the first empirical evidence in support of competing auctions theory using online auctions data from eBay. Our results indicate that a significant proportion of bidders do bid across competing auctions and that bidders tend to submit bids on auctions with the lowest standing bid, as the theory predicts. The paper also shows that winning bidders who cross-bid pay lower prices on average than winning bidders who do not.     

Weak and strong multimarket bidding rings

We consider bidders who are simultaneously participating in private value second-price sealed bid auctions in multiple markets. While active in each market, each bidder is associated with a unique home market in which it can potentially serve as a ring center. Pairs of bidders can establish bilateral agreements to be members of bidding rings in each others’ home markets. Rings can be weak or strong depending respectively on whether side payments are permitted or not. Weak multimarket rings have been shown to take the form of exclusive groups of completely connected bidders. We consider strong multimarket bidding rings and show that they assume a radically different architecture of dominant groups, stars, and interlinked stars. Since bidding rings are tacit, and therefore unobservable, we develop observable implications of multimarket rings that can detect the existence of collusion as well as its form (i.e., weak or strong).     

Bidding behavior in first price sealed bid auctions: Use of computerized Nash competitors

Results are reported from a series of first price sealed bid auctions where bidders face computerized Nash equilibrium competitors. The results provide strong support for employing this newly developed methodology as a testing procedure for Nash equilibrium bidding models.     

Comparing competition and collusion: a numerical approach

Summary. Collusion is a serious problem in many procurement auctions. In this research, I study a model of first price sealed bid procurement auctions with asymmetric bidders. I demonstrate that the equilibrium to the model is unique and describe three algorithms that can be used to compute the inverse equilibrium bid functions. I then use the computational algorithms to compare competitive and collusive bidding. The algorithms are useful for structural estimation of auction models and for assessing the damages from bid-rigging. Received: January 14, 2000; revised version: February 28, 2001     

Bid Functions in Auctions and Fair Division Games: Experimental Evidence

In auctions a seller offers a commodity for sale and collects the revenue. In fair division games the object is collectively owned by the group of bidders who equally share the revenue. We run an experiment in which the participants face four types of allocation games (auctions and fair division game under two price rules, first– versus second–price rule). We collect entire bid functions rather than bids for single values and investigate price and efficiency of the different trading institutions. We find that the first–price auction is more efficient than the second–price auction, whereas economic rationality assuming heterogeneous bidders suggests the opposite. Furthermore, we study the structure of individual bid functions.     

Auctions with shill bidding

Summary. Shill bidding has increased substantially in recent years since the technology employed to conduct on-line auctions enables many sellers to disguise their identities and bid. Although their intent is to gain by misleading the bidders on the value of the object, we show that in a common value auction sellers are worse off shill bidding. In fact, any out-of-auction mechanism that makes it difficult for them to shill bid increases their revenues. In addition, shill bidding reduces the surplus of the bidders and the surplus from trade. It is only the auctioneer who could gain from this activity and in that sense he may not have an incentive from within the auction to discourage shill bidding.Received: 1 February 2002, Revised: 12 August 2003JEL Classification Numbers: D44.Correspondence to: Georgia KosmopoulouWe thank Timothy Dunne, Kevin Grier and the anonymous referees of this journal for helpful comments.     

Asymmetric information about rivals'' types in standard auctions

We study auctions in which bidders may know the types of some rival bidders but not others. This asymmetry in bidders' knowledge about rivals' types has different effects on the two standard auction formats. In a second-price auction, it is weakly dominant to bid one's valuation, so the knowledge of rivals' types has no effect, and the good is allocated efficiently. In a first-price auction, bidders refine their bidding strategies based on their knowledge of rivals' types, which yields an inefficient allocation. We show that the inefficient allocation in the first-price auction translates into a poor revenue performance. Given a standard regularity condition, the seller earns higher expected revenue from the second-price auction than from the first-price auction, whereas the bidders are better off from the latter.     

A comparison of first price multi-object auctions

We compare simultaneous multi-object English-type ascending price auctions with first price sealed bid auctions in private values environments with multi-object demands. Special attention is paid to the effect of closing rules on ascending auctions’ outcomes. We find that simultaneous ascending auctions with the soft closing rule are the most efficient, while the sealed bid auctions generate the highest revenue. Ascending auctions with the hard closing rule display a significant amount of late bidding, resulting in the lowest among the three institutions revenue and efficiency.

---

Electronic Supplementary Material  The online version of this article () contains supplementary material, which is available to authorized users.