AP经济学课件.ppt

AP经济学课件（部分）主讲：傅莹,Lesson11,MonopolyMarket完全垄断市场(Chap15inMankiwsbookandP45-48inAPEconomics)Youwilllearn:thecharacteristicsofpuremonopolymarketandpuremonopolistHowwillmonopolistsmakedecisionsaboutthePrice,Quantity,RevenueandProfitInefficiencyofMonopolyPublicopiniontowardsmonopolyPricediscrimination,Thecharacteristicsofpuremonopolymarketandpuremonopolist完全垄断市场和完全垄断生产者的特点,TheCharacteristicsofPureMonopolist,Afirmisconsideredapuremonopolistifitisthesolesellerofitsproduct.Puremonopolyarerelativelyrare.Inourdiscussion,weregardlesspuremonopoliesandnear-monopoliesasthekindofpuremonopolist.,PureMonopolist,LessPuremonopolistandnear-monopolist,Therearemanyexamplesoflesspuremonopolies.E.ernment-ownedorgovernment-regulatedpublicutilities-naturalgasandelectriccompanies,thewatercompany.Therearealsomany“near-monopolies”inwhichasinglefirmhasabulkofsalesinaspecificmarket.E.g.Intelprovides80%ofthecentralmicroprocessorsusedinpersonalcomputers.,TheCharacteristicsofPureMonopolist(continued),Itsproductdoesnothaveanyclosesubstitutes.Apuremonopolyfirmisapricemaker.Thefundamentalcauseofmonopolyisbarrierstoentry.,DifferentLevelsofBarriertoEntry,Inpuremonopolymarket,strongbarrierstoentryblockallpotentialcompetition.Somewhatweakerbarriersmaypermitoligopoly,amarketstructuredominatedbyfewfirms.Stillweakerbarriersmaypermittheentryofafairlylargenumberofcompetingfirmsgivingrisetomonopolisticcompetition.Finally,theabsenceofanyeffectiveentrybarrierspermitstheentryofaverylargenumberoffirms,whichprovidethebasisofpure(perfect)competition.,WHYMONOPOLIESARISE,Onesinglefirmownsakeyresource.(e.g.AtonetimetheInternationalNickelCompanyofCanada,Inco,controlled90%oftheworldsknownnickelreserves.)Onesinglefirmownsthepatentforacertainproduct.Thegovernmentgivesasinglefirmtheexclusiverighttoproducesomegood.(E.g.ChinaStateGrid)Politicalreasons,Protectingreasonsetc.NaturalMonopolyindustry,HowwillmonopolistsmakedecisionsaboutthePrice,Quantity,RevenueandProfit完全垄断企业如何决定价格、生产数量、收益和利润,AMonopolistsTotalRevenue,AverageRevenue,andMarginalRevenue,Copyright2004South-Western,PMR,PMR,AMonopolistsRevenue,AMonopolistsMarginalRevenueAmonopolistsmarginalrevenueisalwayslessthanthepriceofitsgood.(MR1,InelasticEd0).(12%answeredcorrectly),ProfitMaximizationforaMonopolist(利润最大化）,Copyright2004South-Western,Quantity,Q,0,Costsand,Revenue,AMonopolistsProfit,Profit=TR-TCProfit=(TR/Q-TC/Q)QProfit=(P-ATC)Q,TheMonopolistsEconomicProfit(经济利润）,Copyright2004South-Western,Quantity,0,Costsand,Revenue,Themonopolistwillreceiveeconomicprofitsaslongaspriceisgreaterthanaveragetotalcost.(PATC),TheMonopolistsEconomicLoss(经济亏损）2012FRQ(1),InefficiencyofMonopolists(垄断的无效率性）Youwilllearn:(1)theinefficiencyanddeadweightlossofmonopolists(2)theresponseofgovernmentformonopolists,Recall:EfficiencyofCompetitivefirms,Allocativeefficiencyrequiresthatresourcesbeapportionedamongfirmsandindustriestoyieldthemixofproductsandservicesthtmostwantedbysociety.Themoneypriceofanyproductissocietysmeasureoftherelativeworthofanadditionalunitofthatproduct-forexample,cucumbers.Sothepriceofaunitofcucumbersisthemarginalbenefitderivedfromthatunitoftheproduct.Similarly,weseethatthemarginalcostofadditionalunitofaproductmeasuresthevalueoftheotherresourcesaredrawnawayfromproducingothergoods.P=MCAtequilibriumquantity,thecombinedamountofconsumersurplusandproducersurplusismaximized,TheEfficiencyoftheEquilibriumQuantity,Copyright2003Southwestern/ThomsonLearning,Quantity,Price,0,ConsumerandProducerSurplusintheMarketEquilibrium(Marketefficiency),Copyright2003Southwestern/ThomsonLearning,Price,0,Quantity,Efficiencylosses(Deadweightloss),D,S,Price(PerBag),P1,Q1,Quantity(Bags),Efficiency,Losses,Q2,Q3,6-27,Quantitlylevleslessthanorgreaterthantheefficientquantity,Q1,createefficiencylosses.ThetrangledbeshowstheefficiencylossassociatedwithunderproductionQ2,wherethetrianglebfgillustratestheefficiecylossassociatedwithoverproductionQ3.,InefficiencyofMonopolist,Incontrasttoacompetitivefirm,themonopolychargesapriceabovethemarginalcost.(PMC),thennotallcustomerswhovaluethegoodaboveitscostcanbuyit.Fromthestandpointofconsumers,thishighpricemakesmonopolyundesirable.However,fromthestandpointoftheownersofthefirm,thehighpricemakesmonopolyverydesirable.Fewtransactionaremadeundermonopoly,whichproducedeadweightloss.,TheInefficiencyofMonopoly,Copyright2004South-Western,Becauseamonopolysetsitspriceabovemarginalcost,itplacesawedgebetweentheconsumerswillingnesstopayandtheproducerscost.Thiswedgecausesthequantitysoldtofallshortofthesocialoptimum.,Quantity,0,Price,TheMonopolistsefficiencyandDeadweightloss,Copyright2004South-Western,Quantity,0,Costsand,Revenue,Compare:Thedeadweightlossoftax,Copyright2004South-Western,Quantity,0,Price,Deadweightlossfromlargetax,Copyright2004South-Western,Quantity,0,Price,(c)LargeTax,ChinesegovernmentShouldCuttheTaxes.,TheDeadweightLoss,TheInefficiencyofMonopolyThemonopolistproduceslessthanthesociallyefficientquantityofoutput.Thedeadweightlosscausedbyamonopolyissimilartothedeadweightlosscausedbyatax.Thedifferencebetweenthetwocasesisthatthe(1)governmentgetstherevenuefromatax,(2)aprivatefirmgetsthemonopolyprofit.,Theconditionforallocativeefficiencyisviolatedif(A)firmsarepricemakers(pricesearchers)(B)short-runprofitsexistinacompetitiveindustry(C)priceequalsaveragetotalcost(D)themarketdemandcurveisinelasticinacompetitiveindustry(E)themarketdemandcurveiselasticinacompetitiveindustry,PublicpolicytowardsMonopoly处理完全垄断的公共政策,PUBLICPOLICYTOWARDMONOPOLIES,Governmentrespondstotheproblemofmonopolyinoneoffourways.Makingmonopolizedindustriesmorecompetitive.Regulatingthebehaviorofmonopolies.Turningsomeprivatemonopoliesintopublicenterprises.Doingnothingatall.,(1)IncreasingCompetitionbyantitrustlaw,Antitrustlaws(反垄断法)areacollectionofstatutesaimedatcurbingmonopolypower.Antitrustlawsgivegovernmentvariouswaystopromotecompetition.Theyallowgovernmenttopreventmergers.Theyallowgovernmenttobreakupcompanies.Theypreventcompaniesfromperformingactivitiesthatmakemarketslesscompetitive.TwoImportantAntitrustLawsShermanAntitrustAct(1890)ClaytonAct(1914),(2)Regulation,Governmentmayregulatethepricesthatthemonopolycharges.Theallocationofresourceswillbeefficientifpriceissettoequalmarginalcost.(P=MC)IfP=MC,werealizetheefficientallocationofsocialresources.,MonopolyPrice,Fair-ReturnPrice,SociallyOptimalPrice,Pr,D,r,f,b,a,Pf,Pm,Qm,Qf,Qr,MR,MC,ATC,10-39,P=MCPricingStrategy,MarginalCostPricingforaNaturalMonopoly,Copyright2004South-Western,Quantity,0,Price,P=MC,Inpractice,regulatorswillallowmonopoliststokeepsomeofthebenefitsfromlowercostsintheformofhigherprofit,apracticethatrequiressomedeparturefrommarginal-costpricing.,(3)Turningsomeprivatemonopoliesintopublicenterprises,Ratherthanregulatinganaturalmonopolythatisrunbyaprivatefirm,thegovernmentcanrunthemonopolyitself(heUnitedStates,thegovernmentrunsthePostalService).Thepurposeistorealizeeconomicofscaleandlowerthecost.,(4)DoingNothing,Governmentcandonothingatallifthemarketfailureisdeemedsmallcomparedtotheimperfectionsofpublicpolicies.,PriceDiscrimination价格歧视,PRICEDISCRIMINATION,Pricediscriminationisthebusinesspracticeofsellingthesamegoodatdifferentpricestodifferentcustomers,eventhoughthecostsforproducingforthetwocustomersarethesame.ConditionsMonopolypower(atleastsomedegreeofmonoplypower)Marketsegregation(thesellermustbeabletosegregatebuyersintodistinctclasses)Noresale(theoriginalpurchasercannotreselltheproductorservice),PRICEDISCRIMINATION,PerfectPriceDiscriminationPerfectpricediscriminationreferstothesituationwhenthemonopolistknowsexactlythewillingnesstopayofeachcustomerandcanchargeeachcustomeradifferentprice.Twoimportanteffectsofpricediscrimination:Itcanincreasethemonopolistsprofits.Itcanreducedeadweightloss.,MonopolistwithSinglePrice,Copyright2004South-Western,Price,0,Quantity,MonopolistwithPerfectPriceDiscrimination,Copyright2004South-Western,Price,0,Quantity,一级价格歧视：对每一单位产品都按消费者所愿意支付的最高价格出售，厂商剥夺了全部的消费者剩余。在此情况下资源的配置是有效率的。,MC,Qm,Qc,Pm,Pc,一级价格歧视,PEFECTPRICEDISCRIMINATION（firstdegreepricediscrimination),PRICEDISCRIMINATION,ExamplesofPriceDiscriminationMovieticketsAirlinepricesDiscountcouponsFinancialaidQuantitydiscounts,NaturalMonopolies,Evenathigherquantityproduced,whenafirmsaveragetotalcost(ATC)willdecreaseasthequantitysuppliedincreases.Anaturalmonopolyariseswhenthereareeconomiesofscaleovertherelevantrangeofoutput.Anaturalmonopolyslowerunitcostwouldenableittochargealowerpricethaniftheindustryweremorecompetitive,butnotnecessarilyhappen.Naturalmonopoliesindustry:tapwater,electricity,publictransportationetc.,自然垄断的一个主要特征是厂商的平均成本在很高的产量水平上仍随产量的增加而递减。这方面是自然垄断表现出的规模经济。自然垄断作为垄断的一种形式，同样存在着由于缺乏竞争所造成的垄断厂商高价格、高利润以及低产出水平等经济的效率损失。对自然垄断的争论：政府对某些公用事业的垄断，不以追求垄断利润为目的；对于完全垄断下的技术进步人们持有着不同看法。,自然垄断和政府管制,EconomiesofScaleasaCauseofMonopoly,Copyright2004South-Western,QuantityofOutput,0,Cost,Economiesofscalerefertothepropertywherebylong-runaveragetotalcostfallsasthequantityofoutputincreasesEconomiesofscalewillserveasanentrybarrierandwillprotectthemonopolistfromcompetition.,TypicalAverageTotalCostCurve,Copyright2004South-Western,Quantityof,CarsperDay,0,Average,Total,Cost,MarginalCostPricingforaNaturalMonopoly,Copyright2004South-Western,Quantity,0,Price,P=MCloss,Inpractice,regulatorswillallowmonopoliststokeepsomeofthebenefitsfromlowercostsintheformofhigherprofit,apracticethatrequiressomedeparturefrommarginal-costpricing.,管制机构陷入了两难困境。平均成本定价法Thenp=ATCnoprofit是管制价格等于平均成本,。,第一节垄断七、自然垄断和政府管制,MR,MC,ATC,d(AR),定价法,MonopolyPrice,Fair-ReturnPrice,SociallyOptimalPrice,Pr,D,r,f,b,a,Pf,Pm,Qm,Qf,Qr,MR,MC,ATC,10-56,Somekeypointsinmonopolycurves完全垄断市场中一些重要的点总结,2011Micro1(a)(b),Answer,(a)monopolyprice=24MR=MC(b)24-18=$6,2011.Micro1(c),Question:Assumethatthemonopolistismaximizingprofit.Isallocativeefficiencyachieved?Explain.,Micro1(c),Price,Quantity,Demand,0,MarginalRevenue,MarginalCost,PM,QM,QS,PS,2011.Micro1(c),Answer:No,becausePMC/DMC/MSBMSC.(33%answeredcorrectly),2011.Micro1(d),Question:Betweenthepricesof$16and$18,isthemonopolistintheelastic,inelastic,orunitelasticportionofitsdemandcurve.Explain.,Micro1(d)Answer,Price,Quantity,Demand,0,$16,MarginalRevenue,$18,11,12,Inelasticrange,2011.Micro1(d),Answer:DemandisinelasticbecauseTRincreasesaspriceincreases/MRisnegative/thepriceelasticityis.741.,27%answeredcorrectly,2011Micro(e),2011.Micro1(e),Assumethatregulatorssetanoutputof11units(i)Isthemonopolistearningpositiveeconomicprofit?Explain.Answer:whenQ=11,P=ATC,notearningeconomicprofit.(ii)Isthemonopolistearningpositiveaccountingprofit?Answer:Yes,2011.Micro1(f),Question:Assumethatregulatorsimposeapriceceilingof$22.Whatisthemarginalrevenueoftheeighthunit?Whatquantitywillbeproduced?,Micro1(