“…Common-value auctions, in which the value of the object being sold is unknown but the same to all bidders ex post and each bidder receives a private signal that is correlated with the value, have been studied intensively, both theoretically and empirically, since Milgrom and Weber (MW) (1982); see the surveys by McAfee and McMillan (1987, Section X), Milgrom (1985, Section 4;1987, Section 4), Wilson (1992, Section 4.2), and Klemperer (1999).…”