In many auction settings, there is favoritism: the seller's welfare depends positively on the utility of a subset of potential bidders. However, laws or regulations may not allow the seller to discriminate among bidders. We find the optimal nondiscriminatory auction in a private value,...

We examine the problem of endogenous entry in a single-unit auction when the seller's welfare depends positively on the utility of a subset of potential bidders. We show that, unless the seller values those bidders?welfare more than her own ?private?utility, a nondiscriminatory auction is optimal.