Effects of minimum bid increment in internet auctions: Evidence from a field experiment

I study the role of minimum bid increments (MBI) in internet auctions using field experiment data. I sell identical gift cards while varying the MBI. Internet auctions have typically been viewed as second-price, implying truthful bidding. However, due to the presence of the MBI, equilibrium bidding behavior involves bid-shading. I test between truthful bidding and equilibrium bidding. Truthful bidding is rejected. Bidders conduct bid-shading in a pattern consistent with equilibrium bidding. I also report that the revenue maximizing level for the MBI is higher than zero and the eBay level is close to optimal. Moreover, a high MBI inefficiently limits entry.