耶鲁大学金融市场英文文本FinancialMarketsLecture23Transcript.docx

耶鲁大学金融市场英文文本FinancialMarketsLecture23Transcript.docx

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耶鲁大学金融市场英文文本FinancialMarketsLecture23Transcript

FinancialMarkets:

Lecture23Transcript

ProfessorRobertShiller:

TodayIwanttotalkaboutoptions.Ishouldjustsaywhatanoptionis.I'llwritetheword.It'sacontractthathasanownerandtheowneroftheoptioncontracthasrightstofindinthecontracteithertobuyorsellsomething--let'ssayashareofstock--ataspecifiedpriceandspecifieddate.Therearetwokinds;there'saputandacall.Aputoptionistherighttosell.It'stypicallyahundredshares,sowe'llsayahundredsharesofacompany;let'ssayit'sGoogle.Theoptionwouldhave--ifitwasaputoptionandtherewasaprice,thenyouwouldhavetherightup--letmesee,there'stheexerciseprice,alsoknownasthestrike,andthere'stheexercisedate.

Ishouldalsoemphasizethattherearetwokindsofoptions.ThereareAmerican,socalled,andEuropean,socalled.IthasnothingtowithwhethertheyareinAmericaorEuropebecauseinEuropetheytradebothAmericanoptionsandEuropeanoptionsandinAmericatheytradebothAmericanoptionsandEuropeanoptions;so,it'sveryunfortunateterminology.TheAmerican--whatthismeans--anAmericanoptionmeanstherighttoexercisetheoptiononanydateuntilandincludingtheexercisedate;withEuropean,it'sonlyonexercisedate.That'swhatthosewordsmean.

So,usuallywe'retalkingaboutAmericanoptions.IfyouhaveanAmericanoption--Americanputoption--onsharesofsomestock,thenyouhavetherightanytimeyoufeellikeit,untiltheexercisedate,tosellthatoptionatthepricespecifiedinthecontract,calledtheexerciseprice.Ifit'sEuropean,youhavetowaituntiltheexercisedateandthenyouhaveonedaywhenyoucandothat.Acalloptionistherighttobuyashareofstockorwhateveritis--whateverisspecifiedintheoption.Inatraditionaloption,therearetwoparties;there'sthebuyoftheoptionandusuallywepresentthemfromtheperspectiveofthebuyeroftheoption.Thebuyeroftheoptionpaysapricetobuytheoption--nottobeconfusedwiththeexerciseprice--andthen,dependingonwhetherit'sAmericanorEuropean,hasuntiltheexercisedatetoexercisetheoption;but,thebuyerdoesn'thavetodoanything.Youcanjustdonothing;youcanbuytheoptionandifyoudonothingitbecomesworthlessbecausetheonlywaytheoptionevergivesyouvalueafteryoubuyitisifyouexerciseit,meaningyousay,Iwillusemyrighttobuyorsell.

Theotherpartyisthewriteroftheoption.Becauseit'sacontract,ithastobebetweentwoparties.Somebodyisontheothersideandyoucandoeitherone;youcaneitherbuyorwriteanoption.Ifyou--letmemakethisclear;ifyouwriteacalloption,thenwhatyouarecommittingyourselftodoasthewriter--yousignthecontractfromthewriter'scontract,whichgoesalongwiththebuyer'scontract.Well,itprovidesrightstothebuyer.Ifyouwriteacalloption,thenyou--andsayit'sAmerican--thenyouaresigningacontract--let'ssayit'sonstock--todeliveronehundredsharestotheotherguy,thebuyer,wheneverthatguyfeelslikeit.Thatguywillpayyouthecontractedprice,soit'snot--itdoesn'tseemlikemuchfuntobeawriterofanoptionbecauseyouhave--you'rejustsittingtherewaitingforthisotherpersontomakeuphisorhermind.There'sabenefit;mainly,yougetthemoney.Thebuyeroftheoptionpaysyouupfrontforprovidingthisrighttothebuyer,sowritersofoptionswritethemhopingthattheyexpireunexercised;that'swhentheymakemoney.Ifyouwriteanoptionandthebuyeroftheoptionpaysyouthemoneyupfrontandthenyouneverhearfromthebuyeragain,thenyou're--that'sthewayyoulikeit.So,youmakemoneybywritingoptionsandhopingthattheydon'tgetexercised.

Ofcourse,youcanwriteaputoptionandthatmeans--ifyouwriteaputoption,youaresigningacontractthatsaysthatwheneverthisotherguyontheotherside,thebuyer,decidesto,thatguywillsellyouahundredsharesatthespecifiedprice.Again,you'relayingyourselfopento,wheneverthisguywantsto,you'vegottoreceiveahundredsharesandpaythemoney.

Now,thesekindsofcontractsareveryoldand,infact,wehadaconferenceovertheweekendattheYaleSchoolofManagementon--itwasaveryinteresting--I'veneverexperiencedanythingquitelikeit.MaybeIshouldputthewebsiteupforyoutolookat.There'sabook;it'scalledTheGreatMirrorofFolly,writtenin1720aboutthestockmarketandtheBeineckeRareBookLibraryhasacopyofit.They'reveryrare--aboutthestockmarketcrashof1720.Didyouknowthattherewasabigstockmarketcrashintheyear1720?

WhatwashappeninginNewHavenin1720?

Well,Iknowonethingthatwashappeningin1720inNewHaven--I'mguessing;I'mprettysure.Youhadsomeprettyangryinvestorswholosteverythinginthes