Editing Auction (section)

==Types==
{{See also|Category:Types of auction}}
Auctions come in a variety of types and categories, which are sometimes not mutually exclusive. Typification of auctions is considered to be a part of [[Auction theory]].<ref>{{cite journal |last1=Klemperer |first1=Paul |title=Auction Theory: A Guide to the Literature |journal=Journal of Economic Surveys |date=July 1999 |volume=13 |issue=3 |pages=227–286 |doi=10.1111/1467-6419.00083|url=http://www.nuff.ox.ac.uk/economics/papers/1999/w12/ectheorya.pdf }}</ref> The economists [[Paul Milgrom]] and [[Robert B. Wilson]] were awarded the 2020 [[Nobel Prize]] for the introduction of new auction types (or formats).<ref>{{cite news |author=Charles Riley |title=Nobel Prize in economics awarded to Paul Milgrom and Robert Wilson for auction theory |url=https://edition.cnn.com/2020/10/12/business/nobel-prize-economics/index.html |access-date=13 October 2020 |work=CNN}}</ref> Auction types share features, which can be summarized into the following list.

===Participants=== <!-- a link to here exists-->

{| class="wikitable"
|-
! scope="col" | [[Forward auction]]
! scope="col" | [[Reverse auction]]
! scope="col" | [[Double auction]]
|-
|[[File:Purchaseauction.svg|frameless|none]]
|[[File:Supplyauction.svg|frameless|none]]
|[[File:Doubleauction.svg|frameless|none]]
|-
! colspan="3"| <math> \operatorname{v}_{1..m} </math> stand for sellers and <math> \operatorname{c}_{1..n} </math> for buyers
|}

Auctions can differ in the number and type of participants. There are two types of participants: a [[buyer]] and a [[Sales|seller]]. A buyer pays to acquire a certain good or service, while a seller offers goods or services for money or barter exchange. There can be single or multiple buyers and single or multiple sellers in an auction. If just one seller and one buyer are participating, the process is not considered to be an auction.<ref>{{cite book |last1=Ganguly |first1=D. |last2=Chakraborty |first2=Samit |title=2008 Ninth ACIS International Conference on Software Engineering, Artificial Intelligence, Networking, and Parallel/Distributed Computing |chapter=E Commerce - Forward and Reverse Auction - A Managerial Tool to Succeed over Business Competitiveness |s2cid=7466904 |pages=447–452 |date=2008 |doi=10.1109/SNPD.2008.51|isbn=978-0-7695-3263-9 }}</ref><ref>{{cite book |last1=Preist |first1=Chris |last2=Bartolini |first2=Claudio |last3=Byde |first3=Andrew |title=Proceedings of the 4th ACM conference on Electronic commerce |chapter=Agent-based service composition through simultaneous negotiation in forward and reverse auctions |s2cid=1868153 |pages=55–63 |date=2003 |doi=10.1145/779928.779936|isbn=1-58113-679-X |citeseerx=10.1.1.1.1755 }}</ref><ref name="priceneg">{{cite journal |last1=Friedrich |first1=Michael |last2=Ignatov |first2=Dmitry |title=General Game Playing B-to-B Price Negotiations |journal=CEUR Workshop Proceedings |date=2019 |volume=2479 |pages=89–99 |url=http://ceur-ws.org/Vol-2479/project2.pdf}}</ref> 
{| class="wikitable"
|-
!  
! Single Seller
! Multiple Sellers
|-
! Single Buyer
| [[Trade]]
| [[Reverse auction]]
|-
! Multiple Buyers
| [[Forward auction]]
| [[Double auction]]
|}
The forward auction is the most common type of auction — a seller offers item(s) for sale and expects the highest price. A reverse auction is a type of auction in which the roles of the buyer and the seller are reversed, with the primary objective to drive purchase prices downward.<ref name="Reverse">{{citation
| last1 = Schoenherr
| first1 = Tobias
| last2 = Mabert
| first2 = Vincent A.
| title = Online reverse auctions: Common myths versus evolving reality
| journal = Business Horizons
| volume = 50
| issue = 5
| pages = 373–384
| date = September–October 2007
| doi = 10.1016/j.bushor.2007.03.003
}}</ref> While ordinary auctions provide suppliers the opportunity to find the best price among interested buyers, reverse auctions and [[buyer-determined auction]]s give buyers a chance to find the lowest-price supplier. During a reverse auction, suppliers may submit multiple offers, usually as a response to competing suppliers' offers, bidding down the price of a good or service to the lowest price they are willing to receive. A reverse price auction is not necessarily 'descending-price' —  the reverse [[Dutch auction]] is an ascending-price auction because forward Dutch auctions are descending.<ref>{{Cite web|url=https://www.procurehere.com/the-benefits-of-a-reverse-dutch-auction/|title=The Benefits of a Reverse Dutch Auction|work=Procurehere Blog|language=en-US|date=2018-01-15|access-date=2019-04-30|archive-url=https://web.archive.org/web/20190430125251/https://www.procurehere.com/the-benefits-of-a-reverse-dutch-auction/|archive-date=2019-04-30}}</ref> By revealing the competing bids in real-time to every participating supplier, reverse auctions promote "information transparency". This, coupled with the dynamic bidding process, improves the chances of reaching the fair market value of the item.<ref>{{cite journal
| url = https://www.scribd.com/doc/39032383/Electronic-Reverse-Auction-and-the-Public-Sector-Factors-of-Success-Moshe-E-Shalev-Stee-Asbjorensenf
| first1 = Shalev | last1 = Moshe
| first2 = Asbjornsen | last2 = Stee
| title = Electronic reverse auctions and the public sector – factors of success
| journal = J. Public Procurement
| volume = 10
| issue = 3
| date = Fall 2010
| access-date = 19 January 2014
| pages = 428–452
}}</ref>

A double auction is a combination of both forward and reverse auctions. A [[Walrasian auction]] or ''Walrasian tâtonnement'' is a double auction in which the auctioneer takes bids from both buyers and sellers in a market of multiple goods.<ref name="Milgrom p267">[[#Milgrom2004|Milgrom, 2004: p267]]</ref> The auctioneer progressively either raises or drops the current proposed price depending on the bids of both buyers and sellers, the auction concluding when supply and demand exactly balance.<ref>[[#Milgrom2004|Milgrom, 2004: pp. 267-268]]</ref> As a high price tends to dampen demand while a low price tends to increase demand, in theory there is a particular price somewhere in the middle where supply and demand will match.<ref name="Milgrom p267" /> A '''Barter double auction''' is an auction where every participant has a demand and an offer consisting of multiple attributes and no money is involved.<ref>{{cite arXiv |last1=Tagiew |first1=Rustam |title=Towards Barter Double Auction as Model for Bilateral Social Cooperations |date=22 May 2009 |eprint=0905.3709 |class=cs.GT }}</ref> For the mathematical modelling of satisfaction level, [[Euclidean distance]] is used, where the offer and demand are treated as vectors.

===Price development===
Auctions can be categorized into three types of procedures for auctions depending on the occurrence of a price development<ref name="priceneg"/> during an auction run and its causes.

====Driven by bidders only====
[[File:Auction.jpg|thumb|upright=1.5|An auctioneer and assistants scan the crowd for bidders.]]
* [[English auction]], also known as an ''open ascending price auction''. This type of auction is arguably the most common form of auction in use today.<ref name="#Krishna2002|Krishna, 2002: p2" /> Participants bid openly against one another, with each subsequent bid required to be higher than the previous bid.<ref name="McAfee"/> An auctioneer may announce prices, bidders may call out their bids themselves (or have a proxy call out a bid on their behalf), or bids may be submitted electronically with the highest current bid publicly displayed.<ref name="McAfee" /> In some cases a maximum bid might be left with the auctioneer, who may bid on behalf of the bidder according to the bidder's instructions.<ref name="McAfee" /> The auction ends when no participant is willing to bid further, at which point the highest bidder pays their bid.<ref name="McAfee" /> Alternatively, if the seller has set a minimum sale price in advance (the 'reserve' price) and the final bid does not reach that price the item will remain unsold.<ref name="McAfee" /> Sometimes the auctioneer sets a minimum amount, sometimes known as a bidding increment, by which the next bid must exceed the current highest bid.<ref name="McAfee" /> The most significant distinguishing factor of this auction type is that the current highest bid is always available to potential bidders,<ref name="McAfee" /> although at that time there may be higher absentee bids held by the auctioneer which are not known to potential bidders. The English auction is commonly used for selling goods, most prominently antiques and artwork,<ref name="McAfee" /> but also secondhand goods and [[real estate]].
* [[Auction by the candle]]. A type of auction, used in England for selling ships, in which the highest bid laid on the table wins after a burning candle goes out.
* [[English auction#Scottish auction|Scottish auction]] is an auction where all bidding should be completed within a certain time interval, which allows bidders an appropriate amount of time for consideration and avoids precipitate actions.<ref>{{cite book |last1=Hultmark |first1=Christina |last2=Ramberg |first2=Christina |last3=Kuner |first3=Christopher |title=Internet Marketplaces: The Law of Auctions and Exchanges Online |year=2002 |publisher=Oxford University Press |isbn=978-0-19-925429-3 |url=https://books.google.com/books?id=XlNoeBNcZ80C&pg=PA39 |access-date=29 August 2020 |language=en}}</ref>

====Partially driven by time====
[[File:Bundesarchiv B 145 Bild-F004491-0002, Kirschenversteigerung an der Mosel.jpg|upright=1.5|thumb|A 1957 Dutch auction in Germany to sell fruit]]
* [[Dutch auction]] also known as an ''open descending price auction''.<ref name="#Krishna2002|Krishna, 2002: p2" /> In the traditional Dutch auction the auctioneer begins with a high asking price for some quantity of like items; the price is lowered until a participant is willing to accept the auctioneer's price for some quantity of the goods in the lot or until the seller's reserve price is met.<ref name="McAfee" /> If the first bidder does not purchase the entire lot, the auctioneer continues lowering the price until all of the items have been bid for or the reserve price is reached. Items are allocated based on bid order; the highest bidder selects their item(s) first followed by the second highest bidder, etc. In a modification, all of the winning participants pay only the last announced price for the items that they bid on.<ref name="#Krishna2002|Krishna, 2002: p2" /> The Dutch auction is named for its best known example, the [[Dutch auction|Dutch tulip auctions]]. ("Dutch auction" is also sometimes used to describe online auctions where several identical goods are sold simultaneously to an equal number of high bidders).<ref>{{Citation|author=eBay|title=Selling Multiple Items in a Listing (Dutch Auction)|url=http://pages.ebay.com/help/sell/multiple.html|access-date=2009-01-09|archive-url=https://web.archive.org/web/20081217172337/http://pages.ebay.com/help/sell/multiple.html|archive-date=2008-12-17}}</ref> In addition to cut flower sales in the [[Netherlands]], Dutch auctions have also been used for perishable commodities such as fish and tobacco.<ref name="McAfee" /> The Dutch auction is not widely used, except in market orders in stock or currency exchanges, which are functionally identical.<ref name="#Krishna2002|Krishna, 2002: p2" />
* [[Japanese auction]] is a variation of the Dutch auction with a low initial price that increases over time. As the price rises, participants must either signal intent to continue bidding or drop out of the auction, and no participant may enter or re-enter the auction once it has begun. Once only one participant remains in the auction, the auction ends and that participant wins the item at the current price. It has similarities to the [[Betting (poker)#Ante|ante]] in [[Poker]].<ref>{{cite web |url=http://www.auctusdev.com/auctiontypes.html |title=Auction Types & Terms |publisher=Auctusdev.com |access-date=2012-12-26 |archive-url=https://archive.today/20130117113233/http://www.auctusdev.com/auctiontypes.html |archive-date=2013-01-17 }}</ref>

====Single shot====
* {{vanchor|[[First-price sealed-bid auction]]}},<ref>[http://www.gametheory.net/dictionary/auctions/BlindAuction.html Shor, Mikhael, "blind auction" Dictionary of Game Theory Terms] {{webarchive|url=https://web.archive.org/web/20070504185321/http://www.gametheory.net/Dictionary/Auctions/BlindAuction.html |date=2007-05-04 }}</ref> or a sealed-bid first-price auction/blind auction, is a type of auction where all bidders simultaneously submit sealed bids so that no bidder knows the bid of any other participant. The highest bidder pays the price they submitted.<ref name="#Krishna2002|Krishna, 2002: p2" /><ref name="McAfee" /> This type of auction is distinct from the English auction, in that bidders can only submit one bid each. Furthermore, as bidders cannot see the bids of other participants they cannot adjust their own bids accordingly.<ref name="McAfee" /> From the theoretical perspective, this kind of bid process has been argued to be strategically equivalent to the [[Dutch auction]].<ref>[[#Krishna2002|Krishna, 2002: p13]]</ref> However, empirical evidence from laboratory experiments has shown that Dutch auctions with high clock speeds yield lower prices than FPSB auctions.<ref>{{cite journal |author1=Katok, E. |author2=Kwasnica, A.M. |title = Time is money: The effect of clock speed on seller's revenue in Dutch auctions |journal = [[Experimental Economics]] |volume = 11 |number = 4 |pages = 344–357 |year = 2008 |doi = 10.1007/s10683-007-9169-x|s2cid=17613279 |url = http://www.personal.psu.edu/amk17/TimeIsMoney_onlineversion.pdf }}</ref><ref>{{cite journal |author1=Adam, M. T. P. |author2=Krämer, J. |author3=Weinhardt, C. |s2cid=31932319 |title = Excitement up! Price down! Measuring emotions in Dutch auctions |journal = International Journal of Electronic Commerce |volume = 11 |number = 4 |pages = 7–39 |year = 2012 |doi = 10.2753/JEC1086-4415170201}}</ref> What are effectively sealed first-price auctions are commonly called ''tendering'' for [[procurement]] by companies and organisations, particularly for government contracts and auctions for mining leases.<ref name="McAfee" />
* [[Vickrey auction]], also known as a sealed-bid second-price auction.<ref name="Krishna, 2002: p9">[[#Krishna2002|Krishna, 2002: p9]]</ref> This is identical to the sealed first-price auction except that the winning bidder pays the second-highest bid rather than their own.<ref>[[#Krishna2002|Krishna, 2002: p3]]</ref> Vickrey auctions are extremely important in auction theory, and commonly used in automated contexts such as [[real-time bidding|real-time bidding for online advertising]], but rarely in non-automated contexts.<ref name="McAfee" />

===Properties of auctioned goods===
[[File:The auction in Oulu 1962 (JOKAKAL3B-12356).tif|thumb|250px|The auction in [[Oulu|Oulu, Finland]], in September 1962. Auctioneer shows a table lamp with a final price of [[Finnish markka|FIM]] 6,100.]]
[[Multiunit auction]]s sell more than one identical item at a time, rather than having separate auctions for each. This type can be further classified as either a [[uniform price auction]] or a [[discriminatory price auction]]. An example for them is [[spectrum auction]]s.

A [[combinatorial auction]] is any auction for the simultaneous sale of more than one item where bidders can place bids on an "all-or-nothing" basis on "packages" rather than just individual items. That is, a bidder can specify that they will pay for items A and B, but only if they get ''both''.<ref name="combinatorial">{{Citation
| last1 = Pekec
| first1 = Aleksandar
| last2 = Rothkopf
| first2 = Michael H.
| title = Combinatorial auction design
| journal = Management Science
| volume = 49
| issue = 11
| pages = 1485–1503
| date = November 2003
| doi = 10.1287/mnsc.49.11.1485.20585
| url = http://mansci.journal.informs.org/cgi/content/abstract/53/5/814
| issn = 1526-5501
| bibcode = 2003PNAS..10011153P
| access-date = 2008-06-26
| archive-date = 2007-09-11
| archive-url = https://web.archive.org/web/20070911115539/http://mansci.journal.informs.org/cgi/content/abstract/53/5/814
}}</ref> In combinatorial auctions, determining the winning bidder(s) can be a complex process where even the bidder with the highest individual bid is not guaranteed to win.<ref name="combinatorial" /> For example, in an auction with four items (W, X, Y and Z), if Bidder A offers $50 for items W & Y, Bidder B offers $30 for items W & X, Bidder C offers $5 for items X & Z and Bidder D offers $30 for items Y & Z, the winners will be Bidders B & D while Bidder A misses out because the ''combined'' bids of Bidders B & D is higher ($60) than for Bidders A and C ($55). [[Deferred-acceptance auction]] is a special case of a combinatorial auction.<ref>{{cite CiteSeerX |last1=Milgromy|first1=Paul|last2=Segal|first2=Ilya|title=Deferred-Acceptance Auctions and RadioSpectrum Reallocation|date=September 11, 2014|citeseerx=10.1.1.715.9582}}</ref>

Another special case of a combinatorial auction is the '''combinatorial clock auction''' (CCA), which combines a clock auction, during which bidders may provide their confirmations in response to the rising prices, with a subsequantial sealed bid auction, in which bidders submit sealed package bids. The  auctioneer uses  the final bids to compute the best value allocation and the Vickrey payments.<ref>{{cite book |last1=Bichler |first1=Martin |last2=Goeree |first2=Jacob K. |title=Handbook of Spectrum Auction Design |date=26 October 2017 |publisher=Cambridge University Press |isbn=978-1-107-13534-5 |url=https://books.google.com/books?id=QA44DwAAQBAJ&pg=PA120 |access-date=22 October 2020 |language=en}}</ref><ref>{{cite journal |last1=Ausubel |first1=Lawrence M. |last2=Baranov |first2=Oleg |title=A Practical Guide to the Combinatorial Clock Auction |journal=The Economic Journal |date=1 October 2017 |volume=127 |issue=605 |pages=F334–F350 |doi=10.1111/ecoj.12404 |s2cid=26571660 |url=https://academic.oup.com/ej/article-abstract/127/605/F334/5069450 |language=en |issn=0013-0133}}</ref>

[[Generalized first-price auction]]s and [[Generalized second-price auction]]s offer slots for multiple bidders instead of making a single deal. The bidders get the slots according to the ranking of their bids. The second-price ruling is derived from the [[Vickrey auction]] and means the final deal sealing for the number one bidder is based on the second bidder's price.

===Reserve price===

A [[No-reserve auction]] (NR), also known as an ''absolute auction'', is an auction in which the item for sale will be sold regardless of price.<ref name="Fisher">{{Citation |last1= Fisher |first1= Steven |title= The Real Estate Investor's Handbook: The Complete Guide for the Individual Investor |url= https://archive.org/details/realestateinvest00fish/page/89 |year= 2006 |publisher= Atlantic Publishing Company |location= [[Ocala, Florida]] |isbn= 978-0-910627-69-6 |pages= [https://archive.org/details/realestateinvest00fish/page/89 89–90] |url-access= registration }}</ref><ref name="AuctionBasics">{{Citation |last1= Good |first1= Steven L. |author2= Lynn, Paul A. |date= January 2007 |title= The eBay Effect |journal= Commercial Investment Real Estate |publisher= [[Certified Commercial Investment Member|CCIM Institute]] |url= http://www.ciremagazine.com/article.php?article_id=1036 |access-date= 2009-06-25 |archive-url= https://web.archive.org/web/20101031004055/http://ciremagazine.com/article.php?article_id=1036 |archive-date= 2010-10-31 }}</ref> From the seller's perspective, advertising an auction as having no [[Reservation price|reserve price]] can be desirable because it potentially attracts a greater number of bidders due to the possibility of a bargain.<ref name="Fisher" /> If more bidders attend the auction, a higher price might ultimately be achieved because of heightened competition from bidders.<ref name="AuctionBasics" /> This contrasts with a ''reserve auction'', where the item for sale may not be sold if the final bid is not high enough to satisfy the seller. In practice, an auction advertised as "absolute" or "no-reserve" may nonetheless still not sell to the highest bidder on the day, for example, if the seller withdraws the item from the auction or extends the auction period indefinitely,<ref name="Leichman">{{Citation|title= 90% off! real estate |last1= Leichman |first1= Laurence |year= 1996 |publisher= Leichman Assoc Pubns |location= [[Ocala, Florida]] |isbn= 978-0-9636867-7-0 |pages= 78–79 }}</ref> although these practices may be restricted by law in some jurisdictions or under the terms of sale available from the auctioneer.

A '''reserve auction''' is an auction where the item for sale may not be sold if the final bid is not high enough to satisfy the seller; that is, the seller ''reserves'' the right to accept or reject the highest bid.<ref name="AuctionBasics" /> In these cases, a set 'reserve' price known to the auctioneer, but not necessarily to the bidders, may have been set, below which the item may not be sold.<ref name="Fisher" /> If the seller announces to the bidders the reserve price, it is a public reserve price auction.<ref>{{Cite journal |last1= Riley |first1= J.G.|last2 = Samuelson|first2=W.F. |title= Optimal Auctions. |year= 1981 |journal = The American Economic Review| volume = 71 | pages =  381–392|url = http://www.eecs.harvard.edu/cs286r/courses/spring05/0-150a.pdf}}</ref>  In contrast, if the seller does not announce the reserve price before the sale, it is a secret reserve price auction.<ref>
 {{Cite journal |last1= Elyakime |first1= B.|last2 = Laffont |first2=J.J. |last3=Loisel |first3=P.|last4 = Vuong |first4 = Q. |title= First-Price Sealed-Bid Auctions with Secret Reservation Prices. |year= 1994 |journal = Annales d'Économie et de Statistique | volume = 34 |issue= 34| pages =  115–141 |doi= 10.2307/20075949|jstor =20075949 }}</ref> However, potential bidders may be able to deduce an approximate reserve price, if one exists at all, from any estimate given in advance by the auction house. The reserve price may be ''fixed'' or ''discretionary''. In the latter case, the decision to accept a bid is deferred to the auctioneer, who may accept a bid that is marginally below it. A reserve auction is safer for the seller than a no-reserve auction as they are not required to accept a low bid, but this could result in a lower final price if less interest is generated in the sale.<ref name="AuctionBasics" />

===Price of bidding===<!-- a link point here -->

An [[all-pay auction]] is an auction in which all bidders must pay their bids regardless of whether they win. The highest bidder wins the item. All-pay auctions are primarily of academic interest, and may be used to model lobbying or bribery (bids are political contributions) or competitions such as a running race.<ref>[[#Milgrom2004|Milgrom, 2004: p119]]</ref> [[Bidding fee auction]], a variation of all-pay auction, also known as a penny auction, often requires that each participant must pay a fixed price to place each bid, typically one penny (hence the name) higher than the current bid. When an auction's time period expires, the highest bidder wins the item and must pay a final bid price.<ref>{{cite news|url=http://www.huffingtonpost.com/grace-nasri/the-seduction-of-the-penn_b_846221.html|title=The Seduction of the Penny Auction|access-date=2011-04-27 | work=Huffington Post|first1=Grace|last1=Nasri|date=2011-04-07}}</ref> Unlike in a conventional auction, the final price is typically much lower than the value of the item, but all bidders (not just the winner) will have paid for each bid placed; the winner will buy the item at a very low price (plus price of rights-to-bid used), all the losers will have paid, and the seller will typically receive significantly more than the value of the item.<ref name="reviewopedia">{{cite web|title=QuiBids.com Reviews – Legit or Scam?|url=http://reviewopedia.com/workathome/quibids-com-reviews-is-quibids-a-scam/|publisher=Reviewopedia.com|access-date=13 November 2012|archive-date=1 February 2013|archive-url=https://archive.today/20130201080830/http://reviewopedia.com/workathome/quibids-com-reviews-is-quibids-a-scam/}}</ref> A '''senior auction''' is a variation on the all-pay auction, and has a defined loser in addition to the winner. The top two bidders must pay their full final bid amounts, and only the highest wins the auction. The intent is to make the high bidders bid above their upper limits. In the final rounds of bidding, when the current losing party has hit their maximum bid, they are encouraged to bid over their maximum (seen as a small loss) to avoid losing their maximum bid with no return (a very large loss). Another variation of all-pay auction, the '''top-up auction''' is primarily used for charity events. Losing bidders must pay the difference between their bid and the next lowest bid. The winning bidder pays the amount bid for the item, without top-up. In a [[Chinese auction]], bidders make sealed bids in advance and their probability of winning grows with the relative size of their bids.<ref name="chinese">{{cite web|url=https://www.fundraiserhelp.com/chinese-auction.htm|title=Chinese Auction|website=Fundraising Help|date=17 January 2006}}</ref>

===Structure of a bid===

In usual auctions like the English one, bids are prices. In Dutch and Japanese auctions, the bids are confirmations. In a version of the [[Brazilian auction]], bids are numbers of units being traded. Structure elements of a bid are called attributes. If a bid is one number like price, it is a '''single-attribute auction'''. If bids consists of multiple-attributes, it is a [[multi-attribute auction]].<ref>{{cite journal |last1=Pla |first1=Albert |last2=López |first2=Beatriz |last3=Murillo |first3=Javier |last4=Maudet |first4=Nicolas |title=Multi-attribute auctions with different types of attributes: Enacting properties in multi-attribute auctions |journal=Expert Systems with Applications |date=August 2014 |volume=41 |issue=10 |pages=4829–4843 |doi=10.1016/j.eswa.2014.02.023|hdl=10256/9601 |hdl-access=free }}</ref><ref>{{cite journal |last1=Huang |first1=He |last2=Liu |first2=Liming |last3=Parker |first3=Geoffrey |last4=Tan |first4=Yinliang (Ricky) |last5=Xu |first5=Hongyan |title=Multi-Attribute Procurement Auctions in the Presence of Satisfaction Risk |journal=Production and Operations Management |date=26 December 2018 |volume=28 |issue=5 |pages=1206–1221 |doi=10.1111/poms.12979|doi-access=free }}</ref>

A [[Yankee auction]] is a single-attribute multiunit auction running like a Dutch auction, where the bids are the portions of a total amount of identical units.<ref>{{cite web|title=Yankee Auction|url= http://www.gametheory.net/dictionary/Auctions/YankeeAuction.html|website=Game Theory .net}}</ref><ref>{{cite web|title=Cigar Auctioneer|url=https://www.cigarauctioneer.com/help/auction_help_formats.cfm}}</ref><ref>{{cite web|title=E-Auctions in Sourcing: Yankee Auction|website=eSourcing {{!}} Wiki|url=http://www.esourcingwiki.com/index.php/E-Auctions_in_Sourcing#Yankee_Auction|access-date=2020-02-07|archive-date=2020-01-27|archive-url=https://web.archive.org/web/20200127200654/http://www.esourcingwiki.com/index.php/E-Auctions_in_Sourcing#Yankee_Auction}}</ref> The amount of auctioned items is firm in a Yankee auction unlike a Brazilian auction. The portions of the total amount, bidders can bid, are limited to lower numbers than the total amount. Therefore, only a portion of the total amount will be traded for the best price and the rest to the suboptimal prices.

===Visibility of bids===<!--several pages link here-->

In an English auction, all current bids are visible to all bidders and in a sealed-bid auction, bidders only get to know if their bid was the best. '''Best/not best auctions''' are sealed-bid auctions with multiple bids, where the bidders submit their prices like in English auction and get responses about the leadership of their bid.<ref>{{cite journal |last1=Eichstädt |first1=Tilman |title=Designing Reverse Auctions for B-2-B Procurement Evidence from the German Industry |journal=Negotiation and Market Engineering |series=Dagstuhl Seminar Proceedings |date=2007 |volume=6461 |pages=1–9 |url=http://drops.dagstuhl.de/opus/volltexte/2007/994/ |publisher=Internationales Begegnungs- und Forschungszentrum für Informatik (IBFI), Schloss Dagstuhl, Germany|doi=10.4230/DagSemProc.06461.8 |doi-access=free }}</ref> '''Rank auction''' is an extension of best/not best auction, where the bidders also see the rank of their bids.<ref>{{cite book |last1=Eichstädt |first1=Tilman |chapter=Applying Auction Theory to Procurement Auctions – an Empirical Study Among German Corporations |title=Negotiation, Auctions, and Market Engineering |volume=2 |date=2008 |pages=58–67 |doi=10.1007/978-3-540-77554-6_4 |publisher=Springer |language=en|series=Lecture Notes in Business Information Processing |isbn=978-3-540-77553-9 }}</ref> '''Traffic-light auction''' shows traffic lights to bidders as a response to their bids.<ref>{{cite book |last1=Berz |first1=Gregor |title=Game Theory Bargaining and Auction Strategies |pages=144–159 |doi=10.1057/9781137475428_11 |chapter=The Commitment of Negotiation Processes |year=2015 |isbn=978-1-349-69293-4 }}</ref> These traffic lights depend on the position of the last bid in the distribution of all bids.

===Buyout option===

A '''buyout auction''' is an auction with an additional set price (the 'buyout' price) that any bidder can accept at any time during the auction, thereby immediately ending the auction and winning the item. This means that if an item offers its buyout price at the beginning, one participant can stop all other potential participants from bidding at all, or stop the bidding process before the bid price has reached the buyout price.<ref name="buyout">{{Citation
| last1 = Gallien
| first1 = Jérémie
| last2 = Gupta
| first2 = Shobhit
| title = Temporary and Permanent Buyout Prices in Online Auctions
| journal = Management Science
| volume = 53
| issue = 5
| pages = 814–833
| date = May 2007
| doi = 10.1287/mnsc.1060.0650
| issn = 1526-5501 | hdl = 1721.1/7468
| hdl-access = free
}}</ref> If no bidder chooses to utilize the buyout option before the end of bidding, the highest bidder wins and pays their bid.<ref name="buyout" /> Buyout options can be either ''temporary'' or ''permanent''.<ref name="buyout" /> In a temporary-buyout auction the option to buy out the auction is not available after the first bid is placed.<ref name="buyout" /> In a permanent-buyout auction the buyout option remains available throughout the entire auction until the close of bidding.<ref name="buyout" /> The buyout price can either remain the same throughout the entire auction, or vary throughout according to rules or simply as decided by the seller.<ref name="buyout" />

===Winner selection===

The winner selection in most auctions selects the best bid. [[Unique bid auction]]s offer a special winner selection:<ref>{{cite journal |last1=Costa-Gomes |first1=Miguel A. |last2=Shimoji |first2=Makoto |title=Theoretical approaches to lowest unique bid auctions |journal=Journal of Mathematical Economics |date=May 2014 |volume=52 |pages=16–24 |doi=10.1016/j.jmateco.2014.02.011}}</ref> the winner is the bidder with the lowest unique bid. The [[Chinese auction]] selects a winner partially based on randomness.<ref name="chinese"/>

The final price for the selected winner is not always conducted according to their final bid. In the case of the second-price ruling as in a [[Vickrey auction]], the final price for the winner is based on the second bidder's price. A [[Proxy bid]] is a special case of second-price ruling used by [[eBay]], where a predefined increment is added to the second highest bid in response to a yet higher bid.

Auctions with more than one winner are called '''multi-winner auctions'''.<ref>{{cite journal |last1=Zhang |first1=Wen-zhu |last2=Wang |first2=Ling-yun |title=Dynamic spectrum allocation based on one-band multi-winner auction |journal=Journal on Communications |date=2012 |volume=2012-02 |url=http://en.cnki.com.cn/Article_en/CJFDTotal-TXXB201202000.htm}}</ref> [[Multiunit auction]], [[Combinatorial auction]], [[Generalized first-price auction]] and [[Generalized second-price auction]] are multi-winner auctions.

===Cascading===<!--several links pointing to here-->

Auctions can be cascaded, one after the other. For instance, an '''Amsterdam auction''' is a type of premium auction which begins as an English auction. Once only two bidders remain, each submits a sealed bid. The higher bidder wins, paying either the first or second price. Both finalists receive a premium: a proportion of the excess of the second price over the third price (at which English auction ended).<ref>{{cite web | url=http://econwpa.repec.org/eps/mic/papers/0205/0205002.pdf | title=The Amsterdam Auction | access-date=2016-05-24 | archive-url=https://web.archive.org/web/20160629232654/http://econwpa.repec.org/eps/mic/papers/0205/0205002.pdf | archive-date=2016-06-29 }}</ref> An '''Anglo-Dutch auction''' starts as an English or Japanese auction and then continues as a Dutch auction with a reduced number of bidders.<ref>{{cite web|work=Econ 805 – Advanced Micro Theory I|first1=Dan|last1=Quint|title=Lecture 12|date=Oct 16, 2007|url=https://www.ssc.wisc.edu/~dquint/econ805%202007/econ%20805%20lecture%2012.pdf}}</ref><ref>{{cite web |last1=Marszalec |first1=Daniel |title=The Anglo-Dutch Auction |url=http://www.cirje.e.u-tokyo.ac.jp/research/dp/2016/2016cf1021.pdf |access-date=28 January 2020}}</ref> A [[French auction]] is a preliminary sealed-bid auction before the actual auction, whose reserve price it determines. A [[sequential auction]] is an auction where the bidders can participate in a sequence of auctions. A [[Calcutta auction]] is a subtype of sequential auction, where the ordering in the sequence is determined by random.<ref>{{cite book |last1=Seshadri |first1=S |last2=Shapira |first2=Z |last3=Tucci |first3=CL |chapter=Venture capital investing and the "Calcutta Auction" |chapter-url=https://www.researchgate.net/publication/37426708 |editor1=Ginsberg, Ari |editor2=Hasan, Iftekhar |title=New Venture Investment: Choices and Consequences |pages=19–42|isbn=0-444-51239-X |publisher=Elsevier |date=2003}}</ref> A '''simultaneous ascending auction''' is an opposite of a sequential auction, where the auctions are run in parallel.<ref>{{Citation
| last1 = Peter
| first1 = Cramton
| year = 2006
| contribution = Simultaneous Ascending Auctions
| editor-last = Cramton
| editor-first = Peter
| editor2-last = Shoham
| editor2-first = Yoav
| editor3-last = Steinberg
| editor3-first = Richard
| title = Combinatorial Auctions
| place = Cambridge, MA
| publisher = MIT Press
| isbn = 978-0-262-03342-8
}}</ref>

===Other features===

The '''{{vanchor|silent auction}}''' is a variant of the English auction in which bids are written on a sheet of paper. At the predetermined end of the auction, the highest listed bidder wins the item.<ref name="silent">{{Citation
| last1 = Isaac | first1 = R. Mark
| last2 = Schnier | first2 = Kurt
| title = Silent auctions in the field and in the laboratory
| journal = Economic Inquiry
| volume = 43
| issue = 4
| pages = 715–733
| date = October 2005
| doi = 10.1093/ei/cbi050
| s2cid = 153682553
| url = https://ideas.repec.org/a/oup/ecinqu/v43y2005i4p715-733.html
| issn = 0095-2583 | hdl = 10.1093/ei/cbi050
| hdl-access = free
}}</ref> This auction is often used in [[Charitable organization|charity]] events, with many items auctioned simultaneously and "closed" at a common finish time.<ref name="silent" /><ref>{{Cite web|url=http://hotauctioneering.com/silent-auction/silent-auction-closing-time.html|title=Best Silent Auction Closing Time For Your Fundraiser|date=14 April 2016 |language=en-US|access-date=2017-03-29}}</ref> The auction is "silent" in that there is no auctioneer selling individual items;<ref name="silent" /> the bidders write their bids on a bidding sheet often left on a table near the item.<ref>[[#Milgrom2004|Milgrom, 2004: p268]]</ref> At charity auctions, bid sheets usually have a fixed starting amount, predetermined bid increments, and a "guaranteed bid" amount which works the same as a "buy now" amount. Other variations of this type of auction may include sealed bids.<ref name="silent" /> The highest bidder pays the price they submitted.<ref name="silent" />

In '''private value auctions''', every bidder has their own valuation of the auctioned good.<ref>{{Cite web|url=https://en.wikiversity.org/wiki/Economic_Classroom_Experiments/Private_Value_Auctions|title=Economic Classroom Experiments/Private Value Auctions – Wikiversity|website=en.wikiversity.org|language=en|access-date=2019-07-16}}</ref> A [[common value auction]] is opposite, where the valuation of the auctioned good is identical among the bidders.