AP经济学课件.ppt
Copyright 2004 South-Western AP经济学课件（部分）经济学课件（部分）主讲：傅莹主讲：傅莹Copyright 2004 South-WesternLesson 11MonopolyMarket完全垄断市场(Chap15inMankiwsbookandP45-48inAPEconomics)Youwilllearn:(1)thecharacteristicsofpuremonopolymarketandpuremonopolist(2)HowwillmonopolistsmakedecisionsaboutthePrice,Quantity,RevenueandProfit(3)InefficiencyofMonopoly(4)Publicopiniontowardsmonopoly(5)PricediscriminationCopyright 2004 South-WesternThecharacteristicsofpuremonopolymarketandpuremonopolist完全垄断市场和完全垄断生产者的特点Copyright 2004 South-WesternThe Characteristics of Pure MonopolistAfirmisconsideredapuremonopolistifitisthesolesellerofitsproduct.Puremonopolyarerelativelyrare.Inourdiscussion,weregardlesspuremonopoliesandnear-monopoliesasthekindofpuremonopolist.Copyright 2004 South-WesternPure Monopolist,Less Pure monopolist and near-monopolistTherearemanyexamplesoflesspuremonopolies.E.g.government-ownedorgovernment-regulatedpublicutilities-naturalgasandelectriccompanies,thewatercompany.Therearealsomany“near-monopolies”inwhichasinglefirmhasabulkofsalesinaspecificmarket.E.g.Intelprovides80%ofthecentralmicroprocessorsusedinpersonalcomputers.Copyright 2004 South-WesternThe Characteristics of Pure Monopolist(continued)Itsproductdoesnothaveanyclosesubstitutes.Apuremonopolyfirmisaprice maker.Thefundamentalcauseofmonopolyisbarriers to entry.Copyright 2004 South-WesternDifferent Levels of Barrier to EntryInpuremonopolymarket,strongbarrierstoentryblockallpotentialcompetition.Somewhatweakerbarriersmaypermitoligopoly,amarketstructuredominatedbyfewfirms.Stillweakerbarriersmaypermittheentryofafairlylargenumberofcompetingfirmsgivingrisetomonopolisticcompetition.Finally,theabsenceofanyeffectiveentrybarrierspermitstheentryofaverylargenumberoffirms,whichprovidethebasisofpure(perfect)competition.Copyright 2004 South-WesternWHY MONOPOLIES ARISEOnesinglefirmownsakeyresource.(e.g.AtonetimetheInternationalNickelCompanyofCanada,Inco,controlled90%oftheworldsknownnickelreserves.)Onesinglefirmownsthepatentforacertainproduct.Thegovernmentgivesasinglefirmtheexclusiverighttoproducesomegood.(E.g.ChinaStateGrid)Politicalreasons,Protectingreasonsetc.NaturalMonopolyindustryCopyright 2004 South-WesternHowwillmonopolistsmakedecisionsaboutthePrice,Quantity,RevenueandProfit完全垄断企业如何决定价格、生产数量、收益和利润A Monopolists Total Revenue,Average Revenue,and Marginal RevenueCopyright2004 South-WesternP MRP MRCopyright 2004 South-WesternA Monopolists RevenueAMonopolistsMarginalRevenueAmonopolistsmarginalrevenueisalwaysless thanthepriceofitsgood.(MR 1InelasticEd 0).(12%answeredcorrectly)Profit Maximization for a Monopolist(利润最大化）Copyright 2004 South-WesternQuantityQQ0Costs andRevenueDemandAverage total costMarginal revenueMonopolypriceQMAXB1.The intersection of themarginal-revenue curveand the marginal-costcurve determines theprofit-maximizingquantity.A2.and then the demandcurve shows the priceconsistent with this quantity.MarginalcostCopyright 2004 South-WesternA Monopolists ProfitProfit=TR-TCProfit=(TR/Q-TC/Q)QProfit=(P-ATC)QThe Monopolists Economic Profit(经济利润）Copyright 2004 South-WesternEconomicProfitAveragetotalcostQuantityMonopolypriceQMAX0Costs andRevenueDemandMarginal revenueAverage total costBCEDThemonopolistwillreceiveeconomicprofitsaslongaspriceisgreaterthanaveragetotalcost.(PATC)Marginal costCopyright 2004 South-WesternThe Monopolists Economic Loss(经济亏损）2012 FRQ(1)Copyright 2004 South-WesternInefficiencyofMonopolists(垄断的无效率性）Youwilllearn:(1)theinefficiencyanddeadweightlossofmonopolists(2)theresponseofgovernmentformonopolistsCopyright 2004 South-WesternRecall:Efficiency of Competitive firmsAllocativeefficiencyrequiresthatresourcesbeapportionedamongfirmsandindustriestoyieldthemixofproductsandservicesthtmostwantedbysociety.Themoneypriceofanyproductissocietysmeasureoftherelativeworthofanadditionalunitofthatproduct-forexample,cucumbers.Sothepriceofaunitofcucumbersisthemarginalbenefitderivedfromthatunitoftheproduct.Similarly,weseethatthemarginalcostofadditionalunitofaproductmeasuresthevalueoftheotherresourcesaredrawnawayfromproducingothergoods.P=MCAtequilibriumquantity,thecombinedamountofconsumersurplusandproducersurplusismaximizedCopyright 2004 South-WesternThe Efficiency of the Equilibrium QuantityCopyright2003 Southwestern/Thomson LearningQuantityPrice0SupplyDemandCosttosellersCosttosellersValuetobuyersValuetobuyersValue to buyers is greaterthan cost to sellers.Value to buyers is lessthan cost to sellers.EquilibriumquantityCopyright 2004 South-WesternConsumer and Producer Surplus in the Market Equilibrium(Market efficiency)Copyright2003 Southwestern/Thomson LearningProducersurplusConsumersurplusPrice0QuantityEquilibriumpriceEquilibriumquantitySupplyDemandACBDECopyright 2004 South-WesternEfficiency losses(Deadweight loss)DSPrice (Per Bag)P1Q1Quantity(Bags)EfficiencyLossesQ2Q36-27Quantitly levles less than or greater than the efficient quantity,Q1,create efficiency losses.The trangle dbe shows the efficiency loss associated with underproduction Q2,where the triangle bfg illustrates the efficiecy loss associated with overproduction Q3.Copyright 2004 South-WesternInefficiency of MonopolistIncontrasttoacompetitivefirm,themonopolychargesapriceabovethemarginalcost.(P MC),thennotallcustomerswhovaluethegoodaboveitscostcanbuyit.Fromthestandpointofconsumers,thishighpricemakesmonopolyundesirable.However,fromthestandpointoftheownersofthefirm,thehighpricemakesmonopolyverydesirable.Fewtransactionaremadeundermonopoly,whichproducedeadweightloss.Copyright 2004 South-WesternThe Inefficiency of MonopolyCopyright 2004 South-WesternBecauseamonopolysetsitspriceabovemarginalcost,itplacesawedgebetweentheconsumerswillingnesstopayandtheproducerscost.Thiswedgecausesthequantitysoldtofallshortofthesocialoptimum.Quantity0PriceDeadweightlossDemandMarginalrevenueEfficientquantityMonopolypriceMonopolyquantityMarginal costCopyright 2004 South-WesternThe Monopolists efficiency and Deadweight lossCopyright 2004 South-WesternMonopolyprofitAveragetotalcostQuantityMonopolypriceQMAX0Costs andRevenueDemandMarginal revenueAverage total costBCED Q Effiecent Quantity Marginal costDeadweightlossCopyright 2004 South-WesternCompare:The deadweight loss of tax Copyright 2004 South-Western Quantity0Price DemandSupply=PBQ2=PSPricebuyerspayPricesellersreceive=P1Q1Pricewithout taxDeadweightlossTax RevenueSupply+TaxCopyright 2004 South-WesternDeadweight loss from large taxCopyright 2004 South-WesternTax revenueDemandSupplyQuantity0PriceQ1(c)Large TaxPBQ2PSDeadweightlossChinesegovernmentShouldCuttheTaxes.Copyright 2004 South-WesternThe Deadweight Loss TheInefficiencyofMonopolyThemonopolistproducesless thanthesociallyefficientquantityofoutput.Thedeadweightlosscausedbyamonopolyissimilartothedeadweightlosscausedbyatax.Thedifferencebetweenthetwocasesisthatthe(1)governmentgetstherevenuefromatax,(2)aprivatefirmgetsthemonopolyprofit.Copyright 2004 South-WesternTheconditionforallocativeefficiencyisviolatedif(A)firmsarepricemakers(pricesearchers)(B)short-runprofitsexistinacompetitiveindustry(C)priceequalsaveragetotalcost(D)themarketdemandcurveisinelasticinacompetitiveindustry(E)themarketdemandcurveiselasticinacompetitiveindustryCopyright 2004 South-WesternPublicpolicytowardsMonopoly处理完全垄断的公共政策Copyright 2004 South-WesternPUBLIC POLICY TOWARD MONOPOLIESGovernmentrespondstotheproblemofmonopolyinoneoffourways.Makingmonopolizedindustriesmorecompetitive.Regulatingthebehaviorofmonopolies.Turningsomeprivatemonopoliesintopublicenterprises.Doingnothingatall.Copyright 2004 South-Western(1)Increasing Competition by antitrust lawAntitrustlaws(反垄断法)areacollectionofstatutesaimedatcurbingmonopolypower.Antitrustlawsgivegovernmentvariouswaystopromotecompetition.Theyallowgovernmenttopreventmergers.Theyallowgovernmenttobreakupcompanies.Theypreventcompaniesfromperformingactivitiesthatmakemarketslesscompetitive.TwoImportantAntitrustLawsShermanAntitrustAct(1890)ClaytonAct(1914)Copyright 2004 South-Western(2)RegulationGovernmentmayregulatethepricesthatthemonopolycharges.Theallocationofresourceswillbeefficientifpriceissettoequalmarginalcost.(P=MC)IfP=MC,werealizetheefficientallocationofsocialresources.Copyright 2004 South-Western0Price and Costs(Dollars)QuantityMonopolyPriceFair-ReturnPriceSociallyOptimalPricePrDrfbaPfPmQmQfQrMRMCATC10-39 P=MC Pricing Strategy Copyright 2004 South-WesternMarginal Cost Pricing for a Natural MonopolyCopyright 2004 South-WesternLossQuantity0PriceDemandAverage total costRegulatedpriceMarginal costAverage totalcostP=MCInpractice,regulatorswillallowmonopoliststokeepsomeofthebenefitsfromlowercostsintheformofhigherprofit,apracticethatrequiressomedeparturefrommarginal-costpricing.Copyright 2004 South-Western(3)Turning some private monopolies into public enterprisesRatherthanregulatinganaturalmonopolythatisrunbyaprivatefirm,thegovernmentcanrunthemonopolyitself(e.g.intheUnitedStates,thegovernmentrunsthePostalService).Thepurposeistorealizeeconomicofscaleandlowerthecost.Copyright 2004 South-Western(4)Doing NothingGovernmentcandonothingatallifthemarketfailureisdeemedsmallcomparedtotheimperfectionsofpublicpolicies.Copyright 2004 South-WesternPriceDiscrimination价格歧视Copyright 2004 South-WesternPRICE DISCRIMINATIONPricediscriminationisthebusinesspracticeofsellingthesamegoodatdifferentpricestodifferentcustomers,eventhoughthecostsforproducingforthetwocustomersarethesame.ConditionsMonopolypower(atleastsomedegreeofmonoplypower)Marketsegregation(thesellermustbeabletosegregatebuyersintodistinctclasses)Noresale(theoriginalpurchasercannotreselltheproductorservice)Copyright 2004 South-WesternPRICE DISCRIMINATIONPerfectPriceDiscriminationPerfectpricediscriminationreferstothesituationwhenthemonopolistknowsexactlythewillingnesstopayofeachcustomerandcanchargeeachcustomeradifferentprice.Twoimportanteffectsofpricediscrimination:Itcanincreasethemonopolistsprofits.Itcanreducedeadweightloss.Monopolist with Single PriceCopyright 2004 South-WesternProfitPrice0QuantityDeadweightlossDemandMarginalrevenueConsumersurplusQuantity soldMonopolypriceMarginal costMonopolist with Perfect Price DiscriminationCopyright 2004 South-WesternProfit Price0QuantityDemandMarginal costQuantity sold一级价格歧视一级价格歧视：对：对每一单位产品都按每一单位产品都按消费者所愿意支付消费者所愿意支付的最高价格出售，的最高价格出售，厂商剥夺了全部的厂商剥夺了全部的消费者剩余。消费者剩余。在此情况下资源的在此情况下资源的配置是有效率的。配置是有效率的。oQPMCQmQcPmPc一级价格歧视PEFECT PRICE DISCRIMINATION（first degree price discrimination)Copyright 2004 South-WesternPRICE DISCRIMINATIONExamplesofPriceDiscriminationMovieticketsAirlinepricesDiscountcouponsFinancialaidQuantitydiscountsCopyright 2004 South-WesternNatural MonopoliesEvenathigherquantityproduced,whenafirmsaveragetotalcost(ATC)willdecreaseasthequantitysuppliedincreases.Anaturalmonopolyariseswhenthereareeconomiesofscaleovertherelevantrangeofoutput.Anaturalmonopolyslowerunitcostwouldenableittochargealowerpricethaniftheindustryweremorecompetitive,butnotnecessarilyhappen.Naturalmonopoliesindustry:tapwater,electricity,publictransportationetc.Copyright 2004 South-Western自然垄断的一个主要特征是厂商的平均成本在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。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以及低产出水平等经济的效率损失效率损失。对自然垄断的争论：政府对某些公用事业的垄对自然垄断的争论：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。下的技术进步人们持有着不同看法。自然垄断和政府管制自然垄断和政府管制Copyright 2004 South-WesternEconomies of Scale as a Cause of MonopolyCopyright 2004 South-WesternQuantity of OutputAveragetotalcost0CostEconomies of scale refertothepropertywherebylong-runaveragetotalcostfallsasthequantityofoutputincreasesEconomiesofscalewillserveasanentrybarrierandwillprotectthemonopolistfromcompetition.Copyright 2004 South-WesternTypical Average Total Cost CurveCopyright 2004 South-WesternQuantity ofCars per Day0AverageTotalCostEconomiesofscaleDiseconomiesofscaleConstantreturns toscaleCopyright 2004 South-WesternMarginal Cost Pricing for a Natural MonopolyCopyright 2004 South-WesternLossQuantity0PriceDemandAverage total costRegulatedpriceMarginal costAverage totalcostP=MClossInpractice,regulatorswillallowmonopoliststokeepsomeofthebenefitsfromlowercostsintheformofhigherprofit,apracticethatrequiressomedeparturefrommarginal-costpricing.管制机构陷入管制机构陷入 了两难困境。了两难困境。平均成本定价平均成本定价 法法Thenp=ATCnoprofit是管制价格是管制价格 等于平均成本等于平均成本 。第一节 垄断 七、自然垄断和政府管制oQPMRMCATCd(AR)P2Q2 定价法P1Q1QmPmCopyright 2004 South-Western0Price and Costs(Dollars)QuantityMonopolyPriceFair-ReturnPriceSociallyOptimalPricePrDrfbaPfPmQmQfQrMRMCATC10-56 Some key points in monopoly curves 完全垄断市场中一些重要的点总结Copyright 2004 South-Western2011 Micro 1(a)(b)Copyright 2004 South-WesternAnswer(a)monopolyprice=24MR=MC(b)24-18=$6Copyright 2004 South-Western2011.Micro 1(c)Question:Assumethatthemonopolistismaximizingprofit.Isallocativeefficiencyachieved?Explain.Copyright 2004 South-WesternMicro 1(c)PriceQuantityDemand0MarginalRevenueMarginalCostPMQMQSPSCopyright 2004 South-Western2011.Micro 1(c)Answer:No,becausePMC/DMC/MSBMSC.(33%answeredcorrectly)Copyright 2004 South-Western2011.Micro 1(d)Question:Betweenthepricesof$16and$18,isthemonopolistintheelastic,inelastic,orunitelasticportionofitsdemandcurve.Explain.Copyright 2004 South-WesternMicro 1(d)AnswerPriceQuantityDemand0$16MarginalRevenue$1811 12InelasticrangeCopyright 2004 South-Western2011.Micro 1(d)Answer:DemandisinelasticbecauseTRincreasesaspriceincreases/MRisnegative/thepriceelasticityis.741.27%answeredcorrectlyCopyright 2004 South-Western2011 Micro(e)Copyright 2004 South-Western2011.Micro 1(e)Assumethatregulatorssetanoutputof11units(i)Isthemonopolistearningpositiveeconomicprofit?Explain.Answer:whenQ=11,P=ATC,notearningeconomicprofit.(ii)Isthemonopolistearningpositiveaccountingprofit?Answer:YesCopyright 2004 South-Western2011.Micro 1(f)Question:Assumethatregulatorsimposeapriceceilingof$22.Whatisthemarginalrevenueoftheeighthunit?Whatquantitywillbeproduced?Copyright 2004 South-WesternMicro 1(f)PriceQuantityDemand0MarginalRevenue$229Priceceiling8$24Copyright 2004 South-WesternMicro 1(f)PriceQuantityDemand0MarginalRevenue$229PriceceilingCopyright 2004 South-Western2011.Micro 4(f)Answer:MR=$22.Q=9(12%answeredcorrectly)Copyright 2004 South-WesternMicro 1(f)PriceQuantityDemand0MarginalRevenue$229PriceceilingCopyright 2004 South-Western2011.Micro 1(g)Question:Assumeinsteadthatthemonopolistpracticesperfectpricediscrimination(alsocalledfirst-degreepricediscrimination).(i)Whatquantitywillbeproduced?(ii)Whatwillbethevalueoftheconsumersurplus?Copyright 2004 South-WesternMonopolist with Perfect Price DiscriminationCopyright 2004 South-WesternProfit Price0QuantityDemandMarginal costQuantity soldCopyright 2004 South-Western2011.Micro 1(g)Answer:(i)10unit(ii)Zero(becauseeachcustomerischargedthemostheorsheiswillingtopay,thuseliminatinganyconsumersurplus).(28%answeredcorrectly)Copyright 2004 South-Western2000(10)(12)(24)(27)(40)2000FRQ12005(10)(12)(55)(56)(53)2003FRQ22010FRQ(B)1Copyright 2004 South-WesternSummarythecharacteristicsofpuremonopolymarketandpuremonopolistHowwillmonopolistsmakedecisionsaboutthePrice,Quantity,RevenueandProfitInefficiencyofMonopolyPublicopiniontowardsmonopolyPricediscriminatio
