Early, Late, and Multiple Bidding in Internet Auctions

In Internet auctions bidders frequently bid in one of three ways: either only early, or late, or they revise their early bids. This paper rationalizes all three bidding patterns within a single equilibrium. We consider a model of a dynamic auction in which bidders can search for outside prices during the auction. We find that in the equilibrium bidders with the low search costs bid only late and always search, while the bidders with high search costs bid early or multiple times and search only if they were previously outbid. An important feature of the equilibrium is that early bidding allows bidders to search in a coordinated manner. This means that everyone searches except the bidder with the highest early bid. We also compare the static and dynamic auction and conclude that dynamic auction is always more efficient but not always more profitable.