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1、6InformationandMarketsInPartI,dealingwiththeeconomicsofuncertainty,aftercoveringtheterminaldecisionsoftheindividualinChapters1through3wemovedoninChapter4toconsidermarketequilibrium.Andsimilarlyhereintherealmoftheeconomicsofinformation:havingexaminedindividualsnontermi-nal(informational)de
2、cisionsinChapter5,wenowturntotheanalysisofthemarketequilibriumgeneratedthereby.Afirstkeydistinctionisbetweenpublicandprivateinformation.Ifaninformationserviceprovidespublicinformation,decisionmakersthrough-outtheeconomywillbeattemptingtorevisetheirportfoliosinthelightoftheirchangedbeliefs.
3、Consequently,assetpriceswilladjust.Inparticular,marketvalueswillriseforthoseassetspayingoffmorehandsomelyinstatesoftheworldnowregardedasmorelikely.If,ontheotherhand,themessageprovidedisstrictlyprivate,aninformedpartymaybeabletoprofitinvar-iouswayswithoutanynoticeableeffectuponprices.Howeve
4、r,asweshallsee,almostalwaysthereareprocessesatworktendingtopublicizeprivateinformation.Sometimesthisoccursbecausetheinformedindividualcangainbyintendeddisclosureofhisdata,forexample,ifhesellsittoothers.Orsometimestheremaybeunintendedleakageintothepublicdomainowing,perhaps,tothefactthatthe
5、uninformedcanmonitorthebehaviorofthosewhoareinformed.Thesemoredifficultproblemsarereservedforlaterinthischapter;onlyfullypublicinformationwillbeexaminedinitially.Aseconddistinctionisbetweenproducedandemergentinformation.Informationisproducedwhen,forexample,newevidenceisgeneratedbyasampling
6、experimentconductedbytheagenthimselforbyanexpertonhisbehalf.Ordinarily,somecostisincurredinproducingsuchdata,i.e.,inacquiringsuchamessageservice.Butitmayalsobethatinformationemergescostlessly,simplywiththepassageoftime.Tomorrowsweatherisuncertaintoday,buttheuncertaintywillbereducedasmorem
7、eteorological2246.1TheInter-relatedEquilibriaofPriorandPosteriorMarkets225dataflowinandwillinduecoursebeconclusivelyresolvedwhentomorrowarrives.Whereemergentinformationisanticipated,anindividualmightchooseakindofpassiveinformationalactionsimplywaitingbeforemak-inghis
