Abstract: An electronic auction system known as the Yahoo! Auction System provides functionality that permits users to conduct auction transactions with various payment units, such as incentive points and credit points, as well as money. Points can be earned in a variety of ways and redeemed via online auctions. The Yahoo! Auction System includes a web server, a messaging server, a database server, and various databases including an account database for storing information about account balance, expiration date for each point or group of points, and redemption information. The Yahoo! Auction System provides different auction formats, such as Standard Auction, Dutch Auction, Progressive Auction, Buy-or-Bid Auction, and Declining Bid Auction. The Yahoo! Auction System reserves the bid amount associated any new valid bid in the bidder's account and unreserves those bid amounts that were previously reserved but are no longer the winning bid or otherwise displaced from the top bid positions.