Abstract
In competitive procurement auctions, bids often have the form of unit-price contracts (UPCs). We show that optimal bidding behavior in UPC auctions is typically non-monotonic, and therefore may lead to inefficient allocations. However, UPC auctions may still be desirable for the buyer when compared to efficient mechanisms such as the first-price auction. In a UPC auction, low types are subsidized, and the resulting stronger competition reduces the winning bidder's informational rent, which overcompensates the efficiency loss.