Looking smart versus playing dumb in common-value auctions

I compare the value of information acquired secretly with information acquired openly prior to a first-price common-value auction. Novel information (informationwhich is independent of the other bidder’s private information) ismore valuable when learned openly, but redundant information (information the other bidder already has) is more valuable when learned covertly. In a dynamic game where a bidder can credibly signal he is well-informed without disclosing the content of his information, always signaling having novel information, and never signaling having redundant information, is consistent with (but not uniquely predicted by) equilibrium play. Full revelation of any information possessed by the seller increases expected revenue and is uniquely predicted in equilibrium.