An auction is usually a process of buying and selling goods or services by offering them up for bids, taking bids, and then selling the item to the highest bidder or buying the item from the lowest bidder. Some exceptions to this definition exist and are described in the section about different types. The branch of economic theory dealing with auction types and participants' behavior in auctions is called auction theory.
A Dutch auction is one of several similar types of auctions for buying or selling goods. Most commonly, it means an auction in which the auctioneer begins with a high asking price in the case of selling, and lowers it until some participant accepts the price, or it reaches a predetermined reserve price. This type of price auction is most commonly used for goods that are required to be sold quickly such as flowers, fresh produce, or tobacco. A Dutch auction has also been called a clock auction or open-outcry descending-price auction. This type of auction shows the advantage of speed since a sale never requires more than one bid. It is strategically similar to a first-price sealed-bid auction.
An online auction is an auction held over the internet and accessed by internet connected devices. Similar to in-person auctions, online auctions come in a variety of types, with different bidding and selling rules.
A Vickrey auction or sealed-bid second-price auction (SBSPA) is a type of sealed-bid auction. Bidders submit written bids without knowing the bid of the other people in the auction. The highest bidder wins but the price paid is the second-highest bid. This type of auction is strategically similar to an English auction and gives bidders an incentive to bid their true value. The auction was first described academically by Columbia University professor William Vickrey in 1961 though it had been used by stamp collectors since 1893. In 1797 Johann Wolfgang von Goethe sold a manuscript using a sealed-bid, second-price auction.
A Japanese auction is a dynamic auction format. It proceeds in the following way.
A bidding fee auction, also called a penny auction, is a type of all-pay auction in which all participants must pay a non-refundable fee to place each small incremental bid. The auction is extended each time a new bid is placed, typically by 10 to 20 seconds. Once time expires without a new bid being placed, the last bidder wins the auction and pays the amount of that bid. The auctioneer profits from both the fees charged to place bids and the payment for the winning bid; these combined revenues frequently total more than the value of the item being sold. Empirical evidence suggests that revenues from these auctions exceeds theoretical predictions for rational agents. This has been credited to the sunk cost fallacy. Such auctions are typically held over the Internet, rather than in person.
Auction sniping is the practice, in a timed online auction, of placing a bid likely to exceed the current highest bid as late as possible—usually seconds before the end of the auction—giving other bidders no time to outbid the sniper. This can be done either manually or by software on the bidder's computer, or by an online sniping service.
A double auction is a process of buying and selling goods with multiple sellers and multiple buyers. Potential buyers submit their bids and potential sellers submit their ask prices to the market institution, and then the market institution chooses some price p that clears the market: all the sellers who asked less than p sell and all buyers who bid more than p buy at this price p. Buyers and sellers that bid or ask for exactly p are also included. A common example of a double auction is stock exchange.
Auction theory is an applied branch of economics which deals with how bidders act in auction markets and researches how the features of auction markets incentivise predictable outcomes. Auction theory is a tool used to inform the design of real-world auctions. Sellers use auction theory to raise higher revenues while allowing buyers to procure at a lower cost. The conference of the price between the buyer and seller is an economic equilibrium. Auction theorists design rules for auctions to address issues which can lead to market failure. The design of these rulesets encourages optimal bidding strategies among a variety of informational settings. The 2020 Nobel Prize for Economics was awarded to Paul R. Milgrom and Robert B. Wilson “for improvements to auction theory and inventions of new auction formats.”
A multiunit auction is an auction in which several homogeneous items are sold. The units can be sold each at the same price or at different prices.
Proxy bidding is an implementation of an English second-price auction used on eBay, in which the winning bidder pays the price of the second-highest bid plus a defined increment. It differs from a Vickrey auction in that bids are not sealed; the "current highest bid" is always displayed.
Bidding is an offer to set a price tag by an individual or business for a product or service or a demand that something be done. Bidding is used to determine the cost or value of something.
Revenue equivalence is a concept in auction theory that states that given certain conditions, any mechanism that results in the same outcomes also has the same expected revenue.
A Vickrey–Clarke–Groves (VCG) auction is a type of sealed-bid auction of multiple items. Bidders submit bids that report their valuations for the items, without knowing the bids of the other bidders. The auction system assigns the items in a socially optimal manner: it charges each individual the harm they cause to other bidders. It gives bidders an incentive to bid their true valuations, by ensuring that the optimal strategy for each bidder is to bid their true valuations of the items; it can be undermined by bidder collusion and in particular in some circumstances by a single bidder making multiple bids under different names. It is a generalization of a Vickrey auction for multiple items.
Market design is a practical methodology for creation of markets of certain properties, which is partially based on mechanism design. In some markets, prices may be used to induce the desired outcomes — these markets are the study of auction theory. In other markets, prices may not be used — these markets are the study of matching theory.
The generalized first-price auction (GFP) is a non-truthful auction mechanism for sponsored search. In sponsored search n bidders compete for the assignment of k slots. Each slot has an associate click-through rate, the click-through rates are decreasing from top to bottom. The GFP mechanism asks each bidder for a bid. Then the highest bidder gets the first slot, the second-highest, the second slot and so on. On each click the highest bidder pays his bid on the first slot, the second highest bidder pays his bid on the second slot, and so on.
A Bayesian-optimal mechanism (BOM) is a mechanism in which the designer does not know the valuations of the agents for whom the mechanism is designed, but the designer knows that they are random variables and knows the probability distribution of these variables.
A sequential auction is an auction in which several items are sold, one after the other, to the same group of potential buyers. In a sequential first-price auction (SAFP), each individual item is sold using a first price auction, while in a sequential second-price auction (SASP), each individual item is sold using a second price auction.
In auction theory, jump bidding is the practice of increasing the current price in an English auction, substantially more than the minimal allowed amount.
The Price of Anarchy (PoA) is a concept in game theory and mechanism design that measures how the social welfare of a system degrades due to selfish behavior of its agents. It has been studied extensively in various contexts, particularly in auctions.
