We introduce the groupwise-pivotal referral (GPR) mechanism for auctions where buyers can participate through referrals. Each buyer's type consists of a valuation and referable buyers. Unlike the second-price auction (SPA), the Vickrey-Clarke-Groves (VCG) mechanism provides referral incentives....

We study mechanisms for environments in which only some of the agents are directly connected to a mechanism designer and the other agents can participate in a mechanism only through the connected agents' referrals. In such environments, the mechanism designer and agents may have different...

Consumer protection may induce some socially undesirable outcomes in a competitive bidding environment. In an auction with costly participation, we show that the possibility of default may cause social welfare loss through two channels. One is the possibility of no trade when a default occurs,...

A seller wants to allocate an indivisible product among a number of potential bidders by a finite deadline, and to contact a bidder, she needs to incur a search cost. We show that the seller's optimal search outcomes can be implemented by a sequential search auction, which is characterized by...

We introduce the groupwise-pivotal referral (GPR) mechanism for auctions where buyers can participate only through referrals. Each buyer's type consists of a valuation and referable buyers. Unlike the second-price auction (SPA), the Vickrey-Clarke-Groves (VCG) mechanism provides referral...