Joint Bidding in Common Value Auctions: Theory and Evidence

We examine theoretically and experimentally two countervailing effects of collusion and symmetric mergers among bidders. On one hand, the pooling of information within bidding rings increases the precision of competing estimates. We demonstrate that, in average value auctions, this leads to more aggressive bidding. On the other hand, since collusion decreases the number of active bidders, competition is lessened, reducing the price paid at auction. We demonstrate that the reduction in competition dominates the informational effects, resulting in lower prices. We examine these hypothesized e®ects experimentally by conducting a series of auctions with constant informational content but a varying number of bidders among whom this information is distributed. The experimental results are consistent with our theoretical predictions for different value and auction mechanism specifications.common value auctions, mergers, collusion, information

Ex-Post Full Surplus Extraction, Straightforwardly

Consider an estimate of the common value of an auctioned asset that is symmetric in the bidders' types. Such an estimate can be represented solely in terms of the order statistics of those types. This representation forms the basis for a pricing rule yielding truthful bidding as an equilibrium, whether bidders'types are affiliated or independent. We highlight the link between the estimator and full surplus extraction, providing a necessary and suffient condition for ex-post full surplus extraction, including the possibility of independent types. The results offer sharp insights into the strengths and limits of simple auctions by identifying the source of informational rents in such environments.Auctions, Full Surplus Extraction, Order Statistic Estimates

Ex-Post Full Surplus Extraction, Straightforwardly

Consider an estimate of the common value of an auctioned asset that is symmetric in the bidders' types. Such an estimate can be represented solely in terms of the order statistics of those types. This representation forms the basis for a pricing rule yielding truthful bidding as an equilibrium, whether bidders' types are affiliated or independent. We highlight the link between the estimator and full surplus extraction, providing a necessary and sufficient condition for ex-post full surplus extraction, including the possibility of independent types. The results offer sharp insights into the strengths and limits of simple auctions by identifying the source of informational rents in such environments

Near-optimality of second price mechanisms in a class of asymmetric auctions

Consider a setting with n sellers having i.i.d. costs with log-concave density f from cumulative F, and a buyer who puts a premium [Delta]i on procuring from seller i. We show how for any given [Delta]1,...,[Delta]n, a simple second price bonus auction can be chosen which comes surprisingly close to giving the auctioneer the same surplus as an optimal mechanism. The bonuses depend only on the magnitude and monotonicity of the slope of virtual costs given F. We show that these in turn depend only on fairly coarse information about F. We explore how this result generalizes to asymmetrically distributed costs.Asymmetric auctions Mechanism design Second price auctions Procurement Rho-concavity