Multiple equilibria in asymmetric first-price auctions

Maskin and Riley (2003) and Lebrun (2006) prove that the Bayes-Nash equilibrium of �rst-price auctions is unique. This uniqueness requires the assumption that a buyer never bids above his value. We demonstrate that, in asymmetric �rst-price auctions (with or without a minimum bid), the relaxation of this assumption results in additional equilibria that are "substantial." Although in each of these additional equilibria no buyer wins with a bids above his value, the allocation of the object and the selling price may vary among the equilibria. Furthermore, we show that such phenomena can only occur under asymmetry in the distributions of values.Asymmetric auctions, �first-price auctions, multiple equilibria

Competition among Sellers in Securities Auctions

We study simultaneous security-bid second-price auctions with competition among sellers for potential bidders. The sellers compete by designing ordered sets of securities that the bidders can offer as payment for the assets. Upon observing auction designs, potential bidders decide which auctions to enter. We characterize all symmetric equilibria and show that there always exist equilibria in which auctions are in standard securities or their combinations. In large markets the unique equilibrium is auctions in pure cash. We extend the model for competition in reserve prices and show that binding reserve prices never constitute equilibrium as long as equilibrium security designs are not call options. (JEL D44, D82, G10)

Speculation in Standard Auctions with Resale

We analyze the role resale creates for zero-value bidders, called speculators, in standard auctions with symmetric independent private values buyers. English/second-price auctions always have equilibria with active resale markets and positive profits for a speculator. In first- price/Dutch auctions, the unique equilibrium can involve an active resale market, but is never profitable for a speculator. In all standard auctions, allowing resale can increase the initial seller's revenue and lead to an inefficient allocation. First-price and second-price auctions are not revenue equivalent.first-price, second-price, English, Dutch auctions, speculation, resale, efficiency

Speculation in Standard Auctions with Resale

In standard auctions with symmetric, independent private value bidders resale creates a role for a speculator—a bidder who is commonly known to have no use value for the good on sale. For second-price and English auctions the efficient value-bidding equilibrium coexists with a continuum of inefficient equilibria in which the speculator wins the auction and makes positive profits. First-price and Dutch auctions have an essentially unique equilibrium, and whether or not the speculator wins the auction and distorts the final allocation depends on the number of bidders, the value distribution, and the discount factor. Speculators do not make profits in first-price or Dutch auctions

Speculation in Standard Auctions with Resale

In standard auctions with symmetric, independent private value bidders resale creates a role for a speculator - a bidder who is commonly known to have no use value for the good on sale. For second-price and English auctions the efficient value-bidding equilibrium coexists with a continuum of inefficient equilibria in which the speculator wins the auction and makes positive profits. First-price and Dutch auctions have an essentially unique equilibrium, and whether or not the speculator wins the auction and distorts the final allocation depends on the number of bidders, the value distribution, and the discount factor. Speculators do not make profits in first-price or Dutch auctions.standard auctions, speculation, resale, efficiency

Auctioning Securities

Treasury debt and other divisible securities are traditionally sold in either a pay-your-bid (discriminatory) auction or a uniform-price auction. We compare these auction formats with a Vickrey auction and also with two ascending-bid auctions. The Vickrey auction and the alternative ascending-bid auction (Ausubel 1996) have important theoretical advantages for sellers. In a setting without private information, these auctions achieve the maximal revenue as a unique equilibrium in dominant strategies. In contrast, the pay- your-bid, uniform-price, and standard ascending-bid auction admit a multiplicity of equilibria that yield low revenues for the seller. We show how these results extend to a setting where bidders have affiliated private information. Our results question the standard ways that securities are offered to the public.Auctions; Multi-Unit Auctions, Security Auctions, Treasury Auctions

All-pay auctions with budget constraints and fair insurance.

We study all-pay auctions with budget-constrained bidders who have access to fair insurance before bidding simultaneously over a prize. We characterize a unique equilibrium for the special cases of two bidders and one prize, show existence and a heuristic for finding an equilibrium in the case of multiple bidders and multiple prizes. We end with an example of non-uniqueness of equilibria for the general case of multiple prizes and multiple players.all-pay auctions; fair lotteries; political campaigning; oligopoly; regional competition; patent races

First-Price and Second-Price Auctions with Resale

We add a resale stage to standard auctions with two bidders. Bids are either kept secret or made public. Either the auction winner or the auction loser chooses the resale price. We characterize an infinity of equilibria of the second-price auction and a unique equilibrium of the first-price auction. For every equilibrium of an auction without bid disclosure, we construct an outcome-equivalent and, in the case of the second-price auction, “posterior implementable” equilibrium of the auction with bid disclosure. We compare the revenues from the two auctions and from the two bargaining procedures at resaleAuctions, resale

On the Efficiency of All-Pay Mechanisms

We study the inefficiency of mixed equilibria, expressed as the price of anarchy, of all-pay auctions in three different environments: combinatorial, multi-unit and single-item auctions. First, we consider item-bidding combinatorial auctions where m all-pay auctions run in parallel, one for each good. For fractionally subadditive valuations, we strengthen the upper bound from 2 [Syrgkanis and Tardos STOC'13] to 1.82 by proving some structural properties that characterize the mixed Nash equilibria of the game. Next, we design an all-pay mechanism with a randomized allocation rule for the multi- unit auction. We show that, for bidders with submodular valuations, the mechanism admits a unique, 75% efficient, pure Nash equilibrium. The efficiency of this mechanism outperforms all the known bounds on the price of anarchy of mechanisms used for multi-unit auctions. Finally, we analyze single-item all-pay auctions motivated by their connection to contests and show tight bounds on the price of anarchy of social welfare, revenue and maximum bid.Comment: 26 pages, 2 figures, European Symposium on Algorithms(ESA) 201