Auctions with Endogenous Selling∗

The seminal paper by Milgrom and Weber (1982) ranks the expected rev-enues of several auction mechanisms, taking the decision to sell as exogenous. We endogenize the sale decision. The owner decides whether or not to sell, trading off the conditional expected revenue against his own use value, and buyers take into account the information contained in the owner’s sale deci-sion. We show that revenue ranking implies volume and welfare ranking under certain general conditions. We use this to show that, with affiliated signals, English auctions have larger expected price, volume, and welfare than second-price auctions, which in turn have larger expected price, volume, and welfare than first-price auctions