Proxy bid

Last updated

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" (defined as second-highest bid plus bid increment) is always displayed.

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

eBay American multinational e-commerce corporation

eBay Inc. is an American multinational e-commerce corporation based in San Jose, California that facilitates consumer-to-consumer and business-to-consumer sales through its website. eBay was founded by Pierre Omidyar in the autumn of 1995, and became a notable success story of the dot-com bubble. eBay is a multibillion-dollar business with operations in about 30 countries, as of 2011. The company manages the eBay website, an online auction and shopping website in which people and businesses buy and sell a wide variety of goods and services worldwide. The website is free to use for buyers, but sellers are charged fees for listing items after a limited number of free listings, and again when those items are sold.

A bid price is the highest price that a buyer is willing to pay for a goods. It is usually referred to simply as the "bid".

Description and use

eBay uses the term proxy bidding to refer to their implementation of an English second-price auction, in which the winning bidder pays the price of the second-highest bid, in addition to a defined increment. [1] Though similar to a Vickrey auction, the bids are not sealed. The "current highest bid" (defined as second-highest bid plus bid increment) is always displayed.

A Vickrey auction 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.

Comparison and analysis

In a standard English auction, the winner pays the amount of their bid—regardless of competitors' bids—and it is therefore desirable to place a bid that exceeds the current highest bid by the smallest possible increment.

Conversely, under proxy bidding, the price paid is determined only by competitors' bids and not by the amount of the new bid; this eliminates the economically rational incentive to place a bid below the amount one is willing to pay or to place multiple increasing bids. An "economically rational" bidder will therefore bid the maximum amount they are willing to pay on their first bid, and never raise their bid.

eBay's approach, however, reveals the bidder's limit to rival bidders early in the auction, which can sometimes artificially inflate the price of the item higher than its actual intrinsic value, and ultimately encourages the practice of auction sniping.

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 manually, by software on the bidder's computer, or by an online sniping service.

Related Research Articles

An online auction is an auction which is held over the internet. Online auctions come in many different formats, but most popularly they are ascending English auctions, descending Dutch auctions, first-price sealed-bid, Vickrey auctions, or sometimes even a combination of multiple auctions, taking elements of one and forging them with another. The scope and reach of these auctions have been propelled by the Internet to a level beyond what the initial purveyors had anticipated. This is mainly because online auctions break down and remove the physical limitations of traditional auctions such as geography, presence, time, space, and a small target audience. This influx in reachability has also made it easier to commit unlawful actions within an auction. In 2002, online auctions were projected to account for 30% of all online e-commerce due to the rapid expansion of the popularity of the form of electronic commerce. Online auctions include business to business (B2B), business to consumer (B2C), and consumer to consumer (C2C) auctions. Some of the best examples for online auction sites are eBay, WebStore, OnlineAuction, Overstock and many more.

A Japanese auction is a dynamic auction format. It proceeds in the following way.

The dollar auction is a non-zero sum sequential game designed by economist Martin Shubik to illustrate a paradox brought about by traditional rational choice theory in which players are compelled to make an ultimately irrational decision based completely on a sequence of apparently rational choices made throughout the game.

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 ten to twenty seconds. Without new bids the last participant to have placed a bid wins the item and also pays the final bid price. The auctioneer makes money in two ways: the fees for each bid and the payment for the winning bid, totalling typically significantly more than the value of the item. Such auctions are typically held over the Internet, rather than in person.

Auction theory is an applied branch of economics which deals with how people act in auction markets and researches the properties of auction markets. There are many possible designs for an auction and typical issues studied by auction theorists include the efficiency of a given auction design, optimal and equilibrium bidding strategies, and revenue comparison. Auction theory is also used as a tool to inform the design of real-world auctions; most notably auctions for the privatization of public-sector companies or the sale of licenses for use of the electromagnetic spectrum.

A multiunit auction is an auction in which several items are sold. The units can be sold each at the same price or at different prices.

Tax sale

A tax sale is the forced sale of property by a governmental entity for unpaid taxes by the property's owner.

Bidding is an offer to set a price 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.

The Becker–DeGroot–Marschak method (BDM), named after Gordon M. Becker, Morris H. DeGroot and Jacob Marschak for the 1964 Behavioral Science paper, "Measuring Utility by a Single-Response Sequential Method" is an incentive-compatible procedure used in experimental economics to measure willingness to pay (WTP).

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 is a generalization of a Vickrey auction for multiple items.

In his 2008, Nemmers Prize lecture, Paul Milgrom gave the following definition of market design:

Market design is a kind of economic engineering, utilizing laboratory research, game theory, algorithms, simulations, and more. Its challenges inspire us to rethink longstanding fundamentals of economic theory.

The generalized second-price auction (GSP) is a non-truthful auction mechanism for multiple items. Each bidder places a bid. The highest bidder gets the first slot, the second-highest, the second slot and so on, but the highest bidder pays the price bid by the second-highest bidder, the second-highest pays the price bid by the third-highest, and so on. First conceived as a natural extension of the Vickrey auction, it conserves some of the desirable properties of the Vickrey auction. It is used mainly in the context of keyword auctions, where sponsored search slots are sold on an auction basis. The first analyses of GSP are in the economics literature by Edelman, Ostrovsky, and Schwarz and by Varian. It is employed by Google's AdWords technology.

An ‘‘‘eBidding‘‘‘ is an electronic bidding event according to defined negotiation rules (eAgreement). A buyer and two or more suppliers take part in this online event.

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.

In auction theory, jump bidding is the practice of increasing the current price in an English auction, substantially more than the minimal allowed amount.

References

  1. "Proxy bidding". Archived from the original on 2003-12-03.