Large multi-unit auctions with a large bidder

We compare equilibrium bidding in uniform-price and discriminatory auctions when a single large bidder (i.e., with multi-unit demand) competes against many small bidders, each with single-unit demands. We show that the large bidder prefers the discriminatory auction over the uniform-price auction, and we provide general conditions under which small bidders have the reverse preference. We use examples to show that the efficiency and revenue rankings of the two auctions are ambiguous.