第15章 垄断 曼昆经济学原理第七版.ppt

Monopoly,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,1,WhyMonopoliesArise,MarketpowerAlterstherelationshipbetweenafirmscostsandthesellingpriceMonopolyChargesapricethatexceedsmarginalcostAhighpricereducesthequantitypurchasedOutcome:oftennotthebestforsociety,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,2,WhyMonopoliesArise,GovernmentsCansometimesimprovemarketoutcomeMonopolyFirmthatisthesolesellerofaproductwithoutclosesubstitutesPricemakerCause:barrierstoentry,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,3,WhyMonopoliesArise,BarrierstoentryAmonopolyremainstheonlysellerinthemarketBecauseotherfirmscannotenterthemarketandcompetewithitMonopolyresourcesGovernmentregulationTheproductionprocess,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,4,WhyMonopoliesArise,MonopolyresourcesAkeyresourcerequiredforproductionisownedbyasinglefirmHigherprice,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,5,“Ratherthanamonopoly,weliketoconsiderourselvestheonlygameintown.”,WhyMonopoliesArise,GovernmentregulationGovernmentgivesasinglefirmtheexclusiverighttoproducesomegoodorserviceGovernment-createdmonopoliesPatentandcopyrightlawsHigherpricesHigherprofits,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,6,WhyMonopoliesArise,NaturalmonopolyAsinglefirmcansupplyagoodorservicetoanentiremarketAtasmallercostthancouldtwoormorefirmsEconomiesofscaleovertherelevantrangeofoutputClubgoodsExcludablebutnotrivalinconsumption,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,7,Figure1,8,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,EconomiesofScaleasaCauseofMonopoly,Whenafirmsaverage-total-costcurvecontinuallydeclines,thefirmhaswhatiscalledanaturalmonopoly.Inthiscase,whenproductionisdividedamongmorefirms,eachfirmproducesless,andaveragetotalcostrises.Asaresult,asinglefirmcanproduceanygivenamountattheleastcost,ProductionandPricingDecisions,MonopolyPricemakerSoleproducerDownwardslopingdemand:themarketdemandcurveCompetitivefirmPricetakerOneproducerofmanyDemandisahorizontalline(Price),2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,9,Figure2,10,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,DemandCurvesforCompetitiveandMonopolyFirms,Becausecompetitivefirmsarepricetakers,theyineffectfacehorizontaldemandcurves,asinpanel(a).Becauseamonopolyfirmisthesoleproducerinitsmarket,itfacesthedownward-slopingmarketdemandcurve,asinpanel(b).Asaresult,themonopolyhastoacceptalowerpriceifitwantstosellmoreoutput.,(a)ACompetitiveFirmsDemandCurve,(b)AMonopolistsDemandCurve,Demand,Demand,ProductionandPricingDecisions,AmonopolystotalrevenueTotalrevenue=pricetimesquantityAmonopolysaveragerevenueRevenueperunitsoldTotalrevenuedividedbyquantityAlwaysequalstheprice,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,11,ProductionandPricingDecisions,AmonopolysmarginalrevenueRevenuepereachadditionalunitofoutputChangeintotalrevenuewhenoutputincreasesby1unitMRMR:producelessMaximizeprofitProducequantitywhereMR=MCIntersectionofthemarginal-revenuecurveandthemarginal-costcurvePrice:onthedemandcurve,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,16,Figure4,17,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,ProfitMaximizationforaMonopoly,Amonopolymaximizesprofitbychoosingthequantityatwhichmarginalrevenueequalsmarginalcost(pointA).Itthenusesthedemandcurvetofindthepricethatwillinduceconsumerstobuythatquantity(pointB).,Demand,Marginalrevenue,Marginalcost,QMAX,Monopolyprice,1.Theintersectionofthemarginal-revenuecurveandthemarginal-costcurvedeterminestheprofit-maximizingquantity.,2.andthenthedemandcurveshowsthepriceconsistentwiththisquantity.,Q1,Q2,ProductionandPricingDecisions,ProfitmaximizationPerfectcompetition:P=MR=MCPriceequalsmarginalcostMonopoly:PMR=MCPriceexceedsmarginalcostAmonopolysprofitProfit=TRTC=(PATC)Q,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,18,Figure5,19,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,TheMonopolistsProfit,TheareaoftheboxBCDEequalstheprofitofthemonopolyfirm.Theheightofthebox(BC)ispriceminusaveragetotalcost,whichequalsprofitperunitsold.Thewidthofthebox(DC)isthenumberofunitssold.,Demand,Marginalrevenue,QMAX,Marginalcost,Monopolyprice,Monopolyprofit,Averagetotalcost,MonopolyDrugsversusGenericDrugs,MarketforpharmaceuticaldrugsNewdrug,patentlaws,monopolyProduceQwhereMR=MCPMCGenericdrugs:competitivemarketProduceQwhereMR=MCAndP=MCPriceofthecompetitivelyproducedgenericdrugBelowthemonopolistsprice,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,20,Figure6,21,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,TheMarketforDrugs,Whenapatentgivesafirmamonopolyoverthesaleofadrug,thefirmchargesthemonopolyprice,whichiswellabovethemarginalcostofmakingthedrug.Whenthepatentonadrugrunsout,newfirmsenterthemarket,makingitmorecompetitive.Asaresult,thepricefallsfromthemonopolypricetomarginalcost.,Demand,Marginalrevenue,Monopolyquantity,Priceduringpatentlife,Marginalcost,Priceafterpatentexpires,Competitivequantity,TheWelfareCostofMonopolies,TotalsurplusEconomicwell-beingofbuyersandsellersinamarketSumofconsumersurplusandproducersurplusConsumersurplusConsumerswillingnesstopayforagoodMinustheamounttheyactuallypayforit,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,22,TheWelfareCostofMonopolies,ProducersurplusAmountproducersreceiveforagoodMinustheircostsofproducingitBenevolentplanner:maximizetotalsurplusSociallyefficientoutcomeProducequantitywhereMarginalcostcurveintersectsdemandcurveChargeP=MC,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,23,Figure7,24,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,TheEfficientLevelofOutput,Abenevolentsocialplannermaximizestotalsurplusinthemarketbychoosingthelevelofoutputwherethedemandcurveandmarginal-costcurveintersect.Belowthislevel,thevalueofthegoodtothemarginalbuyer(asreflectedinthedemandcurve)exceedsthemarginalcostofmakingthegood.Abovethislevel,thevaluetothemarginalbuyerislessthanmarginalcost.,Demand(valuetobuyers),Efficientquantity,Marginalcost,Valuetobuyers,Valuetobuyers,Costtomonopolist,Costtomonopolist,TheWelfareCostofMonopolies,MonopolyProducequantitywhereMC=MRProduceslessthanthesociallyefficientquantityofoutputChargePMCDeadweightlossTrianglebetweenthedemandcurveandMCcurve,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,25,Figure8,26,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,TheInefficiencyofMonopoly,Becauseamonopolychargesapriceabovemarginalcost,notallconsumerswhovaluethegoodatmorethanitscostbuyit.Thus,thequantityproducedandsoldbyamonopolyisbelowthesociallyefficientlevel.Thedeadweightlossisrepresentedbytheareaofthetrianglebetweenthedemandcurve(whichreflectsthevalueofthegoodtoconsumers)andthemarginal-costcurve(whichreflectsthecostsofthemonopolyproducer).,Demand,Marginalrevenue,Monopolyquantity,Marginalcost,Monopolyprice,Efficientquantity,Deadweightloss,TheWelfareCostofMonopolies,Themonopolysprofit:asocialcost?Monopoly-higherprofitNotareductionofeconomicwelfareBiggerproducersurplusSmallerconsumersurplusNotasocialproblemSocialloss=DeadweightlossFromtheinefficientlylowquantityofoutput,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,27,PriceDiscrimination,PricediscriminationBusinesspracticeSellthesamegoodatdifferentpricestodifferentcustomersRationalstrategytoincreaseprofitRequirestheabilitytoseparatecustomersaccordingtotheirwillingnesstopayCanraiseeconomicwelfare,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,28,PriceDiscrimination,PerfectpricediscriminationChargeeachcustomeradifferentpriceExactlyhisorherwillingnesstopayMonopolyfirmgetstheentiresurplus(Profit)Nodeadweightloss,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,29,PriceDiscrimination,WithoutpricediscriminationSinglepriceMCConsumersurplusProducersurplus(Profit)Deadweightloss,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,30,Figure9,31,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,WelfarewithandwithoutPriceDiscrimination,Panel(a)showsamonopolythatchargesthesamepricetoallcustomers.Totalsurplusinthismarketequalsthesumofprofit(producersurplus)andconsumersurplus.Panel(b)showsamonopolythatcanperfectlypricediscriminate.Becauseconsumersurplusequalszero,totalsurplusnowequalsthefirmsprofit.Comparingthesetwopanels,youcanseethatperfectpricediscriminationraisesprofit,raisestotalsurplus,andlowersconsumersurplus.,(a)MonopolistwithSinglePrice,(b)MonopolistwithPerfectPriceDiscrimination,Monopolyprice,Quantitysold,Marginalrevenue,Demand,Marginalcost,Quantitysold,Demand,Marginalcost,PriceDiscrimination,ExamplesofpricediscriminationMovieticketsLowerpriceforchildrenandseniorsAirlinepricesLowerpriceforround-tripwithSaturdaynightstay,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,32,“WoulditbotheryoutohearhowlittleIpaidforthisflight?”,PriceDiscrimination,ExamplesofpricediscriminationDiscountcouponsNotallcustomersarewillingtospendtimetoclipcouponsFinancialaidHightuitionandneed-basedfinancialaidWillingnesstopayQuantitydiscountsCustomerpaysahigherpriceforthefirstunitboughtthanforthelastunitbought,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,33,PublicPolicyTowardMonopolies,IncreasingcompetitionwithantitrustlawsShermanAntitrustAct,1890ClaytonAntitrustAct,1914PreventmergersBreakupcompaniesPreventcompaniesfromcoordinatingtheiractivitiestomakemarketslesscompetitive,2015CengageLearning.AllRightsReserved.Maynotbecopied,scanned,orduplicated,inwholeorinpart,exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword-protectedwebsiteforclassroomuse.,34,“ButifwedomergewithAmalgamated,wellhaveenoughresourcestofighttheanti-trustviolationcausedbythemerger.”,PublicPolicyTowardMonop