管理经济学 课件 50页

ManagerialEconomics&BusinessStrategyChapter8ManaginginCompetitive,Monopolistic,andMonopolisticallyCompetitiveMarketsMcGraw-Hill/IrwinMichaelR.Baye,ManagerialEconomicsandBusinessStrategyCopyright©2008bytheMcGraw-HillCompanies,Inc.Allrightsreserved.\nOverviewI.PerfectCompetitionCharacteristicsandprofitoutlook.Effectofnewentrants.II.MonopoliesSourcesofmonopolypower.Maximizingmonopolyprofits.Prosandcons.III.MonopolisticCompetitionProfitmaximization.Longrunequilibrium.8-2\nPerfectCompetitionEnvironmentManybuyersandsellers.Homogeneous(identical)product.Perfectinformationonbothsidesofmarket.Notransactioncosts.Freeentryandexit.8-3\nKeyImplicationsFirmsare“pricetakers”(P=MR).Intheshort-run,firmsmayearnprofitsorlosses.Entryandexitforceslong-runprofitstozero.8-4\nUnrealistic?WhyLearn?Manysmallbusinessesare“price-takers,”anddecisionrulesforsuchfirmsaresimilartothoseofperfectlycompetitivefirms.Itisausefulbenchmark.Explainswhygovernmentsopposemonopolies.Illuminatesthe“danger”tomanagersofcompetitiveenvironments.Importanceofproductdifferentiation.Sustainableadvantage.8-5\nManagingaPerfectlyCompetitiveFirm(orPrice-TakingBusiness)8-6\nSettingPriceFirmQf$DfMarketQM$DSPe8-7\nFirmQf$DfMarketQM$DSPe\nProfit-MaximizingOutputDecisionMR=MC.Since,MR=P,SetP=MCtomaximizeprofits.8-9\nGraphically:RepresentativeFirm’sOutputDecision$QfATCAVCMCPe=Df=MRQf*ATCPeProfit=(Pe-ATC)Qf*8-10\nANumericalExampleGivenP=$10C(Q)=5+Q2OptimalPrice?P=$10OptimalOutput?MR=P=$10andMC=2Q10=2QQ=5unitsMaximumProfits?PQ-C(Q)=(10)(5)-(5+25)=$208-11\n$QfATCAVCMCPe=Df=MRQf*ATCPeProfit=(Pe-ATC)Qf*<0ShouldthisFirmSustainShortRunLossesorShutDown?Loss8-12\nShutdownDecisionRuleAprofit-maximizingfirmshouldcontinuetooperate(sustainshort-runlosses)ifitsoperatinglossislessthanitsfixedcosts.Operatingresultsinasmallerlossthanceasingoperations.Decisionrule:AfirmshouldshutdownwhenPMCToolittleoutput,attoohighaprice.Deadweightlossofmonopoly.8-33\n$QATCMCDMRQMPMMCDeadweightLossofMonopolyDeadweightLossofMonopoly8-34\nArgumentsforMonopolyThebeneficialeffectsofeconomiesofscale,economiesofscope,andcostcomplementaritiesonpriceandoutputmayoutweighthenegativeeffectsofmarketpower.Encouragesinnovation.8-35\nMonopolyMulti-PlantDecisionsConsideramonopolythatproducesidenticaloutputattwoproductionfacilities(thinkofafirmthatgeneratesanddistributeselectricityfromtwofacilities).LetC1(Q2)betheproductioncostatfacility1.LetC2(Q2)betheproductioncostatfacility2.DecisionRule:ProduceoutputwhereMR(Q)=MC1(Q1)andMR(Q)=MC2(Q2)SetpriceequaltoP(Q),whereQ=Q1+Q2.8-36\nMonopolisticCompetition:EnvironmentandImplicationsNumerousbuyersandsellersDifferentiatedproductsImplication:Sinceproductsaredifferentiated,eachfirmfacesadownwardslopingdemandcurve.Consumersviewdifferentiatedproductsasclosesubstitutes:thereexistssomewillingnesstosubstitute.FreeentryandexitImplication:Firmswillearnzeroprofitsinthelongrun.8-37\nManagingaMonopolisticallyCompetitiveFirmLikeamonopoly,monopolisticallycompetitivefirmshavemarketpowerthatpermitspricingabovemarginalcost.levelofsalesdependsonthepriceitsets.But…Thepresenceofotherbrandsinthemarketmakesthedemandforyourbrandmoreelasticthanifyouwereamonopolist.Freeentryandexitimpactsprofitability.Therefore,monopolisticallycompetitivefirmshavelimitedmarketpower.8-38\nMarginalRevenueLikeaMonopolistQQPTR10000102030405010203040508006012004020InelasticElasticElasticInelasticUnitelasticUnitelasticMR8-39\nMonopolisticCompetition:ProfitMaximizationMaximizeprofitslikeamonopolistProduceoutputwhereMR=MC.Chargethepriceonthedemandcurvethatcorrespondstothatquantity.8-40\nShort-RunMonopolisticCompetition$ATCMCDMRQMPMProfitATCQuantityofBrandX8-41\nLongRunAdjustments?Iftheindustryistrulymonopolisticallycompetitive,thereisfreeentry.Inthiscaseother“greedycapitalists”enter,andtheirnewbrandsstealmarketshare.Thisreducesthedemandforyourproductuntilprofitsareultimatelyzero.8-42\n$ACMCDMRQ*P*QuantityofBrandXMR1D1EntryP1Q1LongRunEquilibrium(P=AC,sozeroprofits)Long-RunMonopolisticCompetition8-43\nMonopolisticCompetitionTheGood(ToConsumers)ProductVarietyTheBad(ToSociety)P>MCExcesscapacityUnexploitedeconomiesofscaleTheUgly(ToManagers)P=ATC>minimumofaveragecosts.ZeroProfits(inthelongrun)!8-44\nOptimalAdvertisingDecisionsAdvertisingisonewayforfirmswithmarketpowertodifferentiatetheirproducts.But,howmuchshouldafirmspendonadvertising?Advertisetothepointwheretheadditionalrevenuegeneratedfromadvertisingequalstheadditionalcostofadvertising.Equivalently,theprofit-maximizinglevelofadvertisingoccurswheretheadvertising-to-salesratioequalstheratiooftheadvertisingelasticityofdemandtotheown-priceelasticityofdemand.8-45\nMaximizingProfits:ASynthesizingExampleC(Q)=125+4Q2Determinetheprofit-maximizingoutputandprice,anddiscussitsimplications,ifYouareapricetakerandotherfirmscharge$40perunit;YouareamonopolistandtheinversedemandforyourproductisP=100-Q;YouareamonopolisticallycompetitivefirmandtheinversedemandforyourbrandisP=100–Q.8-46\nMarginalCostC(Q)=125+4Q2,SoMC=8Q.Thisisindependentofmarketstructure.8-47\nPriceTakerMR=P=$40.SetMR=MC.40=8Q.Q=5units.Costofproducing5units.C(Q)=125+4Q2=125+100=$225.Revenues:PQ=(40)(5)=$200.Maximumprofitsof-$25.Implications:Expectexitinthelong-run.8-48\nMonopoly/MonopolisticCompetitionMR=100-2Q(sinceP=100-Q).SetMR=MC,or100-2Q=8Q.Optimaloutput:Q=10.Optimalprice:P=100-(10)=$90.Maximalprofits:PQ-C(Q)=(90)(10)-(125+4(100))=$375.ImplicationsMonopolistwillnotfaceentry(unlesspatentorotherentrybarriersareeliminated).Monopolisticallycompetitivefirmshouldexpectotherfirmstoclone,soprofitswilldeclineovertime.8-49\nConclusionFirmsoperatinginaperfectlycompetitivemarkettakethemarketpriceasgiven.ProduceoutputwhereP=MC.Firmsmayearnprofitsorlossesintheshortrun.…but,inthelongrun,entryorexitforcesprofitstozero.Amonopolyfirm,incontrast,canearnpersistentprofitsprovidedthatsourceofmonopolypowerisnoteliminated.Amonopolisticallycompetitivefirmcanearnprofitsintheshortrun,butentrybycompetingbrandswillerodetheseprofitsovertime.8-50