A new characterization of equilibrium in multiple-object uniform-price auctions

This paper characterizes equilibrium bidding behavior in a multi-unit uniform-price auction. As posited by Noussair (1995) and Engelbrecht-Wiggans and Kahn (1998), when bidders demand two units and valuations are independent, equilibrium bidding behavior entails bidding their values for the first unit, and bidding below their valuations for the second unit. We identify some errors in the analysis of Noussair (1995) and Engelbrecht-Wiggans and Kahn (1998), and provide a characterization of equilibrium behavior which involves a threshold value that separates bidders who bid zero for the second unit from those who shade their bids for the second unit.