Internet auctions, such as those on eBay, are known for multiple bidding and sniping. Buyers send bids in the closing seconds of an auction, knowing that bids arriving after the closure of the auction are not counted. They also bid several times at the same auction. We model Internet auction as...

The use of coarse categories is prevalent in various situations and has been linked to biased economic outcomes, ranging from discrimination against minorities to empirical anomalies in financial markets. In this paper we study economic rationales for categorizing coarsely. We think of the way...