The Competitiveness of Joint Bidding in Multi-Unit Uniform-Price Auctions

Abstract

Recent literature on joint bidding in a single-unit, Common-Value (CV) auction argues that the inference and precision that emerges from pooling information by joint bidders enhances competition. Such information pooling mitigates adverse selection and results in more aggressive bidding and may even increase revenue despite the reduction in the number of bidders. We analyze here, for the first time, joint bidding in a simple CV, uniform-price auction with multi-unit demand. This introduces an opposite force due to (increased) monopsony power of the joint bidders, called demand reduction (DR). We show that the pro-competitive benefit from joint bidding in single unit auctions does not generalize to a multi-unit environment, even when DR is disallowed. With DR, the scope for improved competition is further eroded.