Auction Format and Auction Sequence in Multi-item Multi-unit Auctions: An Experimental Study

We experimentally study the effect of auction format (sealed-bid versus closed clock versus open clock) and auction sequence (simultaneous versus sequential) on bidding behaviour and auction outcomes in auctions of multiple related multi-unit items. Prominent field applications are the sale of emission permits, fishing rights, and electricity. We find that, when auctioning simultaneously, clock auctions outperform sealed-bid auctions in terms of efficiency and revenues. This advantage disappears when the items are auctioned sequentially. In addition, auctioning sequentially has positive effects on total revenues across all auction formats, resulting from fiercer competition on the item auctioned first.