Independent Private Value Auctions: Bidder Behaviour in First-, Second- and Third-Price Auctions with Varying Numbers of Bidders

The symmetric equilibrium of third-price auctions is characterized. It makes a number of contrasting predictions relative to firms and second-price auctions: bids exceed private values, the marginal effects on bids of an increase in private values is greater than one, increasing numbers of bidders reduces bids, and risk aversion requires bidding below the risk neutral Nash equilibrium. In the experiment, bidders do not always satisfy the point predictions of the theory. However, the game theoretic models correctly anticipate, at least directionally, the important effects of the price rule changes. Copyright 1993 by Royal Economic Society.