Equivalence and revenue comparison among identical-item auctions

We compare outcomes of the common identical-item auction formats in an independent private value environment. In single-unit demand cases, discriminatory auctions, uniform-price auctions, sequential auctions with disclosing only the winner's identity, and sequential auctions with disclosing both the winner's identity and winning price, are revenue equivalent. The seller's expected revenue is the lowest in sequential auctions with disclosing all bids due to bidders' faking behaviors. In multi-unit demand cases, discriminatory auctions generate the highest revenue, followed by sequential auctions with three different information disclosure rules. The seller's revenue varies from the highest to the lowest in uniform-price auctions owing to the existence of multiple equilibria. Interestingly, we find that with more information disclosed, a bidder's expected payoff may increase, decrease, or even stay unchanged, which is different from the conventional wisdom "the more information, the better".