清华大学中级微观经济学讲义清华李稻葵

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ChapterSeventeenAuctions清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第1页!WhereareweinthecourseWeareworkingonafewimportantadditionstoourmicroeconomicsframeworkWearediscussingaimportantcaseofnon-petitivemarket清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第2页!WhoUsesAuctions?Ownersofart,cars,stamps,machines,mineralrightsetc.Q:Whyauction?A:Becausemanymarketsareimperfectanditishardtodiscoverpotentialbuyers’truevaluationsofyourasset.Auctionshelptodiscoverthisinformation.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第3页!TypesofAuctionsEnglishauction:bidsarepublicannouncementsbidpricerisesuntiltherearenofurtherbidshighestbidwinswinnerpayshisbid.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第4页!TypesofAuctionsSealed-bidsecond-priceauction:bidsareprivateinformationbidsaremadesimultaneouslyhighestbidderwinswinnerpayssecond-highestbidalsoknownasaVickreyauction.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第5页!ReservePriceAsellerspecifiedbidlevelbelowwhichnosaleismade.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第6页!Economists’ClassificationofAuctionsCommon-valueauctions:itemforsalehasthesamevaluetoeverypotentialbuyerpotentialbuyersdifferintheirownestimatesofthismonvalue.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第7页!AuctionDesignParetoefficiency:theitemmustselltothebuyerwiththehighestvaluationoftheitem.WhichauctionsareParetoefficient?清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第8页!AuctionsandEfficiencyEnglishauctionwithareservepriceneednotbeefficientsinceifthereservepriceissetabovethe(unknowntotheseller)highestbuyervaluation,thentherewillbenosaleandsonogains-to-trade.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第9页!AuctionsandEfficiencySealed-bidfirst-priceauctionneednotbeefficient.Nobuyerknowsotherbuyers’valuations,sothehighestvaluationbuyermaybidtoolowandlosetoanotherbidder.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第10页!WhyUseaReservePrice?Supposethereare2buyers.Thesellerbelieveseachbuyer’svaluationis$20withchance1/2and$50withchance1/2.I.e.withchance1/4each,thesellerbelievesshefacesbuyervaluations($20,$20),($20,$50),($50,$20)and($50,$50).清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第11页!WhyUseaReservePrice?Withchance1/4each,winningbidswillbe$20,$21,$21and$50ifthereisnoreserveprice.Seller’sexpectedrevenueis

($20+$21+$21+$50)/4=$28

withnoreserveprice.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第12页!WhyUseaReservePrice?Setareservepriceof$50.Withchance1/4therewillbenosale.Withchance3/4thewinningbidwillbe$50.Seller’sexpectedrevenueis清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第13页!Second-Price,Sealed-BidAuctionbidsareprivateinformationbidsaremadesimultaneouslyhighestbidderwinswinnerpayssecond-highestbidalsoknownasaVickreyauction.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第14页!Second-Price,Sealed-BidAuctionE.g.twobidderswithtruevaluationsv1andv2.Bidsareb1andb2.Expectedgaintobidder1is清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第15页!Second-Price,Sealed-BidAuctionSincetruth-tellingisbestforeverybidder,thehighestvaluationbidderwillwin.Hencethesecond-price,sealed-bidauctionisPareto-efficient.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第16页!Common-ValueAuctionsBidderi’sestimateis

whereisthemonvalueandisbidderi’sestimationerror.Ifeverybidistruthful,thewinneristhebidderwiththelargestestimationerrorsoatruthfulwinneronaveragepaysmorethanthetruevalue--thewinner’scurse.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第17页!TypesofAuctionsSealed-bidfirst-priceauction:bidsareprivateinformationbidsaremadesimultaneouslyhighestbidwinswinnerpayshisbid.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第18页!TypesofAuctionsDutchauction:auctioneerannouncesahighbidandthengraduallylowersthebidfirstbuyertoacceptwinsandpaysthatprice.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第19页!Economists’ClassificationofAuctionsPrivate-valueauctions:everypotentialbuyerknowsforsureherownvaluationoftheitemforsalealltheseindividualvaluationsareindependentofeachother.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第20页!AuctionDesignGoals:Paretoefficiencymaximizationoftheseller’sprofit.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第21页!AuctionsandEfficiencyEnglishauctionwithnoreservepricemustbeefficientsince,ifabuyerwithalowvaluationwasabouttobuy,thehighestvaluationbuyerwouldbidhigher.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第22页!AuctionsandEfficiencyDutchauctionneednotbeefficient.Nobuyerknowsotherbuyers’valuations,sothehighestvaluationbuyermaydelaytoolongandlosetoanotherbidder.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第23页!AuctionsandEfficiencySealed-bidsecond-priceauctionisParetoefficienteventhoughnobuyerknowstheotherbuyers’valuations(moreonthislater).清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第24页!WhyUseaReservePrice?I.e.withchance1/4each,thesellerbelievesshefacesbuyervaluations($20,$20),($20,$50),($50,$20)and($50,$50).UseanEnglishauction.Bidsmustberaisedbyatleast$1.Withchance1/4each,winningbidswillbe$20,$21,$21and$50ifthereisnoreserveprice.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第25页!WhyUseaReservePrice?Withchance1/4each,thesellerbelievesshefacesbuyervaluations($20,$20),($20,$50),($50,$20)and($50,$50).Setareservepriceof$50.Withchance1/4therewillbenosale.Withchance3/4thewinningbidwillbe$50.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第26页!ReservePriceandEfficiencyThereservepricecausesanefficiencylosssince,withchance1/4,thereisnotrade.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第27页!Second-Price,Sealed-BidAuction

Nobidderknowsanyotherbidder’struevaluationoftheitemforsale.Yet,itisindividuallyrationalforeachbiddertostatetruthfullyhisownvaluation.Why?E.g.twobidderswithtruevaluationsv1andv2.清华大学中级微观经济学讲义清华李稻葵共31页，您现在浏览的是第28页!Second-Price,Sealed-BidAuctionExpectedgaintob