English auction

An English auction is an open-outcry ascending dynamic auction. It proceeds as follows.

Unlike sealed-bid auctions (such as First-price sealed-bid auction or Vickrey auction), an English auction is "open" or fully transparent, as the identity of all bidders is disclosed to each other during the auction. More generally, an auction mechanism is considered "English" if it involves an iterative process of adjusting the price in a direction that is unfavorable to the bidders (increasing in price if the item is being sold to competing buyers or decreasing in price in a reverse auction with competing sellers). In contrast, a Dutch auction would adjust the price in a direction that favored the bidders (lowering the price if the item is being sold to competing buyers, increasing it, if it is a reverse auction).

When the auction involves a single item for sale and each participant has as an independent private value for the item auctioned, the expected payment and expected revenues of an English auction is theoretically equivalent to that of the Vickrey auction, and both mechanisms have weakly dominant strategies. Both the Vickrey and English auction, although very different procedurally, award the item to the bidder with the highest value at a price equal to the value of the second highest bidder.

There are many variations on this auction system. Sometimes, the reserve price is not revealed. Also, bids may be made with instead of being called out. Such signals can include tugging an ear or raising a bidding paddle. Another variation on the English auction is the open-exit auction, where the bidders must announce that they are dropping out of the bidding and they can't reenter. In France, when the last bid has been made in an auction for an art object, a member of the state can say "Préemption de l'état" ("Pre-emption of the state") and buy the object for the highest bid. Some housing cooperatives similarly allow members of the cooperative to pre-empt any buyer of a house constructed by the cooperative. English auctions may end at a specified time, or when no new bids have been made after a period of time. A less regulated auction where the bidders are not bound by their bids, and the seller is free to accept or decline any bid made is sometimes called a Swedish auction, a term originally made up by an English journalist writing about the Swedish real estate market.

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