AbstractThis paper studies the relationship between the auctioneer's provision of information and the level of competition in private value auctions. We use a general notion of informativeness which allows us to compare the efficient with the (privately) optimal amount of information provided by the auctioneer. We show that it is not optimal for the auctioneer to provide the efficient level of information. We also look at the effect of competition as parameterized by the number of participants in the auction. We find that both the optimal and the efficient level of information increase with the number of participants in the auction, and both converge when the number of bidders goes to infinity.