Buyer Alliances as Countervailing Power in WIC Infant-Formula Auctions

State agencies in infant-formula procurement auctions receive lower bids when they are in buyer alliances than when they are unallied. The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) uses an auction to procure infant formula. Manufacturers bid on the right to be an agency’s sole supplier by offering a rebate on formula sold through WIC. Agencies frequently join together in buyer alliances. An empirical estimation shows that bids are lower to alliances and that lower prices result because alliances are heterogeneous. Results suggest that when heterogeneity is not controlled, bids decline with alliance size, which has policy implications because Congress recently limited alliance size.