AP经济学课件.ppt

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1、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,RevenueandPro

2、fit(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 MonopolistAfirmisconsideredapuremonopolistifitisthesolesellerof

3、itsproduct.Puremonopolyarerelativelyrare.Inourdiscussion,weregardlesspuremonopoliesandnear-monopoliesasthekindofpuremonopolist.Copyright 2004 South-WesternPure Monopolist,Less Pure monopolist and near-monopolistTherearemanyexamplesoflesspuremonopolies.E.g.government-ownedorgovernment-regulatedpublic

4、utilities-naturalgasandelectriccompanies,thewatercompany.Therearealsomany“near-monopolies”inwhichasinglefirmhasabulkofsalesinaspecificmarket.E.g.Intelprovides80%ofthecentralmicroprocessorsusedinpersonalcomputers.Copyright 2004 South-WesternThe Characteristics of Pure Monopolist(continued)Itsproductd

5、oesnothaveanyclosesubstitutes.Apuremonopolyfirmisaprice maker.Thefundamentalcauseofmonopolyisbarriers to entry.Copyright 2004 South-WesternDifferent Levels of Barrier to EntryInpuremonopolymarket,strongbarrierstoentryblockallpotentialcompetition.Somewhatweakerbarriersmaypermitoligopoly,amarketstruct

6、uredominatedbyfewfirms.Stillweakerbarriersmaypermittheentryofafairlylargenumberofcompetingfirmsgivingrisetomonopolisticcompetition.Finally,theabsenceofanyeffectiveentrybarrierspermitstheentryofaverylargenumberoffirms,whichprovidethebasisofpure(perfect)competition.Copyright 2004 South-WesternWHY MONO

7、POLIES ARISEOnesinglefirmownsakeyresource.(e.g.AtonetimetheInternationalNickelCompanyofCanada,Inco,controlled90%oftheworldsknownnickelreserves.)Onesinglefirmownsthepatentforacertainproduct.Thegovernmentgivesasinglefirmtheexclusiverighttoproducesomegood.(E.g.ChinaStateGrid)Politicalreasons,Protecting

8、reasonsetc.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 Reve

9、nueAMonopolistsMarginalRevenueAmonopolistsmarginalrevenueisalwaysless 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 inte

10、rsection 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 E

11、conomic Profit(经济利润）Copyright 2004 South-WesternEconomicProfitAveragetotalcostQuantityMonopolypriceQMAX0Costs andRevenueDemandMarginal revenueAverage total costBCEDThemonopolistwillreceiveeconomicprofitsaslongaspriceisgreaterthanaveragetotalcost.(PATC)Marginal costCopyright 2004 South-WesternThe Mon

12、opolists 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 firmsAllocativeefficiencyrequiresthat

13、resourcesbeapportionedamongfirmsandindustriestoyieldthemixofproductsandservicesthtmostwantedbysociety.Themoneypriceofanyproductissocietysmeasureoftherelativeworthofanadditionalunitofthatproduct-forexample,cucumbers.Sothepriceofaunitofcucumbersisthemarginalbenefitderivedfromthatunitoftheproduct.Simil

14、arly,weseethatthemarginalcostofadditionalunitofaproductmeasuresthevalueoftheotherresourcesaredrawnawayfromproducingothergoods.P=MCAtequilibriumquantity,thecombinedamountofconsumersurplusandproducersurplusismaximizedCopyright 2004 South-WesternThe Efficiency of the Equilibrium QuantityCopyright2003 S

15、outhwestern/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(

16、Market efficiency)Copyright2003 Southwestern/Thomson LearningProducersurplusConsumersurplusPrice0QuantityEquilibriumpriceEquilibriumquantitySupplyDemandACBDECopyright 2004 South-WesternEfficiency losses(Deadweight loss)DSPrice (Per Bag)P1Q1Quantity(Bags)EfficiencyLossesQ2Q36-27Quantitly levles less

17、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 MonopolistIncontras

18、ttoacompetitivefirm,themonopolychargesapriceabovethemarginalcost.(P MC),thennotallcustomerswhovaluethegoodaboveitscostcanbuyit.Fromthestandpointofconsumers,thishighpricemakesmonopolyundesirable.However,fromthestandpointoftheownersofthefirm,thehighpricemakesmonopolyverydesirable.Fewtransactionaremade

19、undermonopoly,whichproducedeadweightloss.Copyright 2004 South-WesternThe Inefficiency of MonopolyCopyright 2004 South-WesternBecauseamonopolysetsitspriceabovemarginalcost,itplacesawedgebetweentheconsumerswillingnesstopayandtheproducerscost.Thiswedgecausesthequantitysoldtofallshortofthesocialoptimum.

20、Quantity0PriceDeadweightlossDemandMarginalrevenueEfficientquantityMonopolypriceMonopolyquantityMarginal costCopyright 2004 South-WesternThe Monopolists efficiency and Deadweight lossCopyright 2004 South-WesternMonopolyprofitAveragetotalcostQuantityMonopolypriceQMAX0Costs andRevenueDemandMarginal rev

21、enueAverage 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

22、 2004 South-WesternDeadweight loss from large taxCopyright 2004 South-WesternTax revenueDemandSupplyQuantity0PriceQ1(c)Large TaxPBQ2PSDeadweightlossChinesegovernmentShouldCuttheTaxes.Copyright 2004 South-WesternThe Deadweight Loss TheInefficiencyofMonopolyThemonopolistproducesless thanthesociallyeff

23、icientquantityofoutput.Thedeadweightlosscausedbyamonopolyissimilartothedeadweightlosscausedbyatax.Thedifferencebetweenthetwocasesisthatthe(1)governmentgetstherevenuefromatax,(2)aprivatefirmgetsthemonopolyprofit.Copyright 2004 South-WesternTheconditionforallocativeefficiencyisviolatedif(A)firmsarepri

24、cemakers(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-Wes

25、ternPUBLIC POLICY TOWARD MONOPOLIESGovernmentrespondstotheproblemofmonopolyinoneoffourways.Makingmonopolizedindustriesmorecompetitive.Regulatingthebehaviorofmonopolies.Turningsomeprivatemonopoliesintopublicenterprises.Doingnothingatall.Copyright 2004 South-Western(1)Increasing Competition by antitru

26、st lawAntitrustlaws(反垄断法)areacollectionofstatutesaimedatcurbingmonopolypower.Antitrustlawsgivegovernmentvariouswaystopromotecompetition.Theyallowgovernmenttopreventmergers.Theyallowgovernmenttobreakupcompanies.Theypreventcompaniesfromperformingactivitiesthatmakemarketslesscompetitive.TwoImportantAnt

27、itrustLawsShermanAntitrustAct(1890)ClaytonAct(1914)Copyright 2004 South-Western(2)RegulationGovernmentmayregulatethepricesthatthemonopolycharges.Theallocationofresourceswillbeefficientifpriceissettoequalmarginalcost.(P=MC)IfP=MC,werealizetheefficientallocationofsocialresources.Copyright 2004 South-W

28、estern0Price and Costs(Dollars)QuantityMonopolyPriceFair-ReturnPriceSociallyOptimalPricePrDrfbaPfPmQmQfQrMRMCATC10-39 P=MC Pricing Strategy Copyright 2004 South-WesternMarginal Cost Pricing for a Natural MonopolyCopyright 2004 South-WesternLossQuantity0PriceDemandAverage total costRegulatedpriceMarg

29、inal costAverage totalcostP=MCInpractice,regulatorswillallowmonopoliststokeepsomeofthebenefitsfromlowercostsintheformofhigherprofit,apracticethatrequiressomedeparturefrommarginal-costpricing.Copyright 2004 South-Western(3)Turning some private monopolies into public enterprisesRatherthanregulatingana

30、turalmonopolythatisrunbyaprivatefirm,thegovernmentcanrunthemonopolyitself(e.g.intheUnitedStates,thegovernmentrunsthePostalService).Thepurposeistorealizeeconomicofscaleandlowerthecost.Copyright 2004 South-Western(4)Doing NothingGovernmentcandonothingatallifthemarketfailureisdeemedsmallcomparedtotheim

31、perfectionsofpublicpolicies.Copyright 2004 South-WesternPriceDiscrimination价格歧视Copyright 2004 South-WesternPRICE DISCRIMINATIONPricediscriminationisthebusinesspracticeofsellingthesamegoodatdifferentpricestodifferentcustomers,eventhoughthecostsforproducingforthetwocustomersarethesame.ConditionsMonopo

32、lypower(atleastsomedegreeofmonoplypower)Marketsegregation(thesellermustbeabletosegregatebuyersintodistinctclasses)Noresale(theoriginalpurchasercannotreselltheproductorservice)Copyright 2004 South-WesternPRICE DISCRIMINATIONPerfectPriceDiscriminationPerfectpricediscriminationreferstothesituationwhent

33、hemonopolistknowsexactlythewillingnesstopayofeachcustomerandcanchargeeachcustomeradifferentprice.Twoimportanteffectsofpricediscrimination:Itcanincreasethemonopolistsprofits.Itcanreducedeadweightloss.Monopolist with Single PriceCopyright 2004 South-WesternProfitPrice0QuantityDeadweightlossDemandMargi

34、nalrevenueConsumersurplusQuantity 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

35、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 MonopoliesEvenathigherqu

36、antityproduced,whenafirmsaveragetotalcost(ATC)willdecreaseasthequantitysuppliedincreases.Anaturalmonopolyariseswhenthereareeconomiesofscaleovertherelevantrangeofoutput.Anaturalmonopolyslowerunitcostwouldenableittochargealowerpricethaniftheindustryweremorecompetitive,butnotnecessarilyhappen.Naturalmo

37、nopoliesindustry: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

38、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

39、refertothepropertywherebylong-runaveragetotalcostfallsasthequantityofoutputincreasesEconomiesofscalewillserveasanentrybarrierandwillprotectthemonopolistfromcompetition.Copyright 2004 South-WesternTypical Average Total Cost CurveCopyright 2004 South-WesternQuantity ofCars per Day0AverageTotalCostEcon

40、omiesofscaleDiseconomiesofscaleConstantreturns toscaleCopyright 2004 South-WesternMarginal Cost Pricing for a Natural MonopolyCopyright 2004 South-WesternLossQuantity0PriceDemandAverage total costRegulatedpriceMarginal costAverage totalcostP=MClossInpractice,regulatorswillallowmonopoliststokeepsomeo

41、fthebenefitsfromlowercostsintheformofhigherprofit,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)Quantit

42、yMonopolyPriceFair-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:Ass

43、umethatthemonopolistismaximizingprofit.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

44、.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:Demandisinelast

45、icbecauseTRincreasesaspriceincreases/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,not

46、earningeconomicprofit.(ii)Isthemonopolistearningpositiveaccountingprofit?Answer:YesCopyright 2004 South-Western2011.Micro 1(f)Question:Assumethatregulatorsimposeapriceceilingof$22.Whatisthemarginalrevenueoftheeighthunit?Whatquantitywillbeproduced?Copyright 2004 South-WesternMicro 1(f)PriceQuantityDe

47、mand0MarginalRevenue$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$229Priceceiling

48、Copyright 2004 South-Western2011.Micro 1(g)Question:Assumeinsteadthatthemonopolistpracticesperfectpricediscrimination(alsocalledfirst-degreepricediscrimination).(i)Whatquantitywillbeproduced?(ii)Whatwillbethevalueoftheconsumersurplus?Copyright 2004 South-WesternMonopolist with Perfect Price Discrimi

49、nationCopyright 2004 South-WesternProfit Price0QuantityDemandMarginal costQuantity soldCopyright 2004 South-Western2011.Micro 1(g)Answer:(i)10unit(ii)Zero(becauseeachcustomerischargedthemostheorsheiswillingtopay,thuseliminatinganyconsumersurplus).(28%answeredcorrectly)Copyright 2004 South-Western200

50、0(10)(12)(24)(27)(40)2000FRQ12005(10)(12)(55)(56)(53)2003FRQ22010FRQ(B)1Copyright 2004 South-WesternSummarythecharacteristicsofpuremonopolymarketandpuremonopolistHowwillmonopolistsmakedecisionsaboutthePrice,Quantity,RevenueandProfitInefficiencyofMonopolyPublicopiniontowardsmonopolyPricediscriminatio