Behavior in multi-unit demand auctions: Experiments with uniform price anddynamic Vickrey auctions

We experimentally investigate the sensitivity of bidders demanding multiple units of a homogeneous commodity to the demand reduction incentives inhere nt in uniform price auctions. There is substantial demand reduction in both sealed bid and ascending price clock auctions with feedback regarding riva ls' drop-out prices. Although both auctions have the same normal form repre sentation, bidding is much closer to equilibrium in the ascending price auc tions. We explore the behavioral process underlying these differences along with dynamic Vickrey auctions designed to eliminate the inefficiencies res ulting from demand reduction in the uniform price auctions.