We study the design of profit maximizing single unit auctions under the assumption that the seller needs to incur costs to contact prospective bidders and inform them about the auction. With independent biddersï¾’ types and possibly interdependent valuations, the sellerï¾’s problem can...

We characterize optimal selling mechanisms in auction environments where bidders must incur a cost to learn their valuations. These mechanisms specify for each period, as a function of the bids in previous periods, which new potential buyers should be asked to bid. In addition, these mechanisms...

We study optimal auctions when contacting prospective bidders is costly and the biddersï¾’ values are correlated. Although full surplus extraction is in general impossible, we can construct a search mechanism that fully extracts the surplus with an arbitrarily high probability.