Bundle and separate sales in auctions with entry

A seller sells dissimilar objects while taking the auction rule as given. Should the seller sell the objects separately or as a bundle? Generally, when the number of bidders is small bundling helps to stimulate the competition and raise revenue. In this paper, we show that if entry is costly enough the process of endogenous participation generates sufficient competition to make bundling unnecessary in auctions. Thus whether a bundle auction generates a higher or a lower revenue ultimately depends first on the level of the entry costs and then, possibly, on the number of potential bidders.