昆明理工大学MBA中级微观第章讲义垄断行为

ChapterTwenty-FiveMonopolyBehavior垄断行为HowShouldaMonopolyPrice?Sofaramonopolyhasbeenthoughtofasafirmwhichhastosellitsproductatthesamepricetoeverycustomer.Thisisuniformpricing.Canprice-discrimination（差别定价）earnamonopolyhigherprofits?StructureFirst-degreepricediscriminationSecond-degreepricediscriminationThird-degreepricediscriminationBundlingTwo-parttariffTypesofPriceDiscrimination1st-degree:Eachoutputunitissoldatadifferentprice.Pricesmaydifferacrossbuyers.2nd-degree:Thepricepaidbyabuyercanvarywiththequantitydemandedbythebuyer.Butallcustomersfacethesamepriceschedule.E.g.bulk-buyingdiscounts.TypesofPriceDiscrimination3rd-degree:Pricepaidbybuyersinagivengroupisthesameforallunitspurchased.Butpricemaydifferacrossbuyergroups.

E.g.,seniorcitizenandstudentdiscountsvs.nodiscountsformiddle-agedpersons.First-degreePriceDiscriminationEachoutputunitissoldatadifferentprice.Pricemaydifferacrossbuyers.Itrequiresthatthemonopolistcandiscoverthebuyerwiththehighestvaluationofitsproduct,thebuyerwiththenexthighestvaluation,andsoon.First-degreePriceDiscriminationp(y)y$/outputunitMC(y)Sellthethunitfor$First-degreePriceDiscriminationp(y)y$/outputunitMC(y)Sellthethunitfor$Lateron

sellthethunitfor$First-degreePriceDiscriminationp(y)y$/outputunitMC(y)Sellthethunitfor$Lateron

sellthethunitfor$Finally

sellthethunitformarginal

cost,$First-degreePriceDiscriminationp(y)y$/outputunitMC(y)Thegainstothemonopolist

onthesetradesare:

andzero.Theconsumers’gainsarezero.First-degreePriceDiscriminationp(y)y$/outputunitMC(y)Sothesumofthegainstothemonopolistonalltradesisthemaximumpossibletotalgains-to-trade.PSFirst-degreePriceDiscriminationp(y)y$/outputunitMC(y)Themonopolistgetsthemaximumpossiblegainsfromtrade.PSFirst-degreepricediscriminationisPareto-efficient.First-degreePriceDiscriminationFirst-degreepricediscriminationgivesamonopolistallofthepossiblegains-to-trade,leavesthebuyerswithzerosurplus,andsuppliestheefficientamountofoutput.Examplesof1st-degreePriceDiscriminationAuctionofantiqueCarsalesFinancialaidinuniversitiesMaynotbepracticaldonotknowwillingnesstopaytoocostlyNon-linearpricingUnitpricedependsonquantitypurchasedBulkdiscountSettingAsellerdoesnotknowthewillingnesstopaybyeachindividualbuyerConsumer’smarginalwillingnesstopaydeclineswithquantitySecond-degreePriceDiscriminationSettingauniformpriceisnotoptimalToohighapricewouldlosehighvolumeconsumer.Toolowapricewouldlostrevenuefromlowvolumeconsumer.Cokeexample.Mechanism：：SetpricefordifferentvolumestoletconsumersidentifythemselvesSecond-degreePriceDiscriminationTwoconsumersPerson1haslowwillingness-to-payPerson1hashighwillingness-to-payAssume0MCAnExampleAquantity$/outputunitx10x20CBChargeAforx10hopingtogetperson1ChargeA+B+Cforx20hopingtogetperson2Butperson2isbetteroffbuyingx10andreceivingacs=BFailtoletconsumersself-selectthemselvesProfit=2ACanalternativelychargeA+Cforx20toidentifyperson2profit=2A+CSecond-degreePriceDiscriminationAquantity$/outputunitx10x20CBReducex10soAisreducedbyalittlebutCcanbeincreasedbyalot。Persons1and2arestillidentifiedProfitishigherSecond-degreePriceDiscriminationAquantity$/outputunitMC(y)x1mx20CBProfitismaximizedatx1mSecond-degreePriceDiscrimination2nd-degreediscriminationcanalsooccurinthedimensionofqualityDifferentpricesfordifferentseatsinatheaterDifferentpricesforeconomyclassvs.businessclassseatsinairplanesSecond-degreePriceDiscriminationThird-degreePriceDiscriminationPricepaidbybuyersinagivengroupisthesameforallunitspurchased.Butpricemaydifferacrossbuyergroups.Qualityofgoodsisthesameacrossgroups.Canidentifygroupsbutnofurtheridentificationwithinthatgroup.Third-degreePriceDiscriminationAmonopolistmanipulatesmarketpricebyalteringthequantityofproductsuppliedtothatmarket.Sothequestion““Whatdiscriminatorypriceswillthemonopolistset,oneforeachgroup?”isreallythequestion“Howmanyunitsofproductwillthemonopolistsupplytoeachgroup?”Third-degreePriceDiscriminationTwomarkets,1and2.y1isthequantitysuppliedtomarket1.Market1’sinversedemandfunctionisp1(y1).y2isthequantitysuppliedtomarket2.Market2’sinversedemandfunctionisp2(y2).Third-degreePriceDiscriminationForgivensupplylevelsy1andy2thefirm’sprofitisWhatvaluesofy1andy2maximizeprofit?Third-degreePriceDiscriminationTheprofit-maximizationconditionsareThird-degreePriceDiscriminationandsotheprofit-maximizationconditionsareandThird-degreePriceDiscriminationMR1(y1)=MR2(y2)saysthattheallocationy1,y2maximizestherevenuefromsellingy1+y2outputunits.E.g.ifMR1(y1)>MR2(y2)thenanoutputunit

shouldbemovedfrommarket2tomarket1

toincreasetotalrevenue.üýþThird-degreePriceDiscriminationüýþThemarginalrevenuecommontobothmarketsequalsthemarginalproductioncostifprofitistobemaximized.Third-degreePriceDiscriminationMR1(y1)MR2(y2)y1y2y1*y2*p1(y1*)p2(y2*)MCMCp1(y1)p2(y2)Market1Market2MR1(y1*)=MR2(y2*)=MCandp1(y1*)¹p2(y2*).Third-degreePriceDiscriminationRecallthatandInwhichmarketwillthemonopolistsetthehigherprice?But,Third-degreePriceDiscriminationSoTherefore,onlyifThemonopolistsetsthehigherpriceinthemarketwheredemandisleastown-priceelastic.Examplesof3rd-degreePriceDiscriminationDiscountstostudents,seniorcitizensBusinesstravelersandvacationersGovernmentandprivate-sectorpurchasersCouponsandrebatesFirst-runmoviesanddollarmovieHardcoverbooksandpaperbackbooksBundlingTypesofconsumersWordprocessorSpreadsheetTypeA120100TypeB100120WillingnesstopayforsoftwarecomponentsTwoMarketingPoliciesSellseparately:Wordprocessor:p=100,revenue=200Speadsheet;p=100,revenue=200BundlingSetp=220forthebundleRevenue=440Two-PartTariffsAtwo-parttariffisalump-sumfee,p1,plusapricep2foreachunitofproductpurchased.Thusthecostofbuyingxunitsofproductisp1+p2x.Two-PartTariffsShouldamonopolistpreferatwo-parttarifftouniformpricing,ortoanyoftheprice-discriminationschemesdiscussedsofar?Ifso,howshouldthemonopolistdesignitstwo-parttariff?Two-PartTariffsp1+p2xQ:Whatisthelargestthatp1canbe?A:p1isthe“entrancefee””sothelargestitcanbeisthesurplusthebuyergainsfromenteringthemarket.Setp1=CSandnowaskwhatshouldbep2?Two-PartTariffsp(y)y$/outputunitMC(y)Shouldthemonopolist

setp2aboveMC?Two-PartTariffsp(y)y$/outputunitCSShouldthemonopolist

setp2aboveMC?p1=CS.MC(y)Two-PartTariffsp(y)y$/outputunitCSShouldthemonopolist

setp2aboveMC?p1=CS.PSisprofitfromsales.MC(y)PSTwo-PartTariffsp(y)y$/outputunitCSShouldthemonopolist

setp2aboveMC?p1=CS.PSisprofitfromsales.MC(y)PSTotalprofitTwo-PartTariffsp(y)y$/outputunitShouldthemonopolist

setp2=MC?MC(y)Two-PartTariffsp(y)y$/outputunitShouldthemonopolist

setp2=MC?p1=CS.CSMC(y)Two-PartTariffsp(y)y$/outputunitShouldthemonopolist

setp2=MC?p1=CS.PSisprofitfromsales.MC(y)CSPSTwo-PartTariffsp(y)y$/outputunitShouldthemonopolist

setp2=MC?

p1=CS.

PSisprofitfromsales.MC(y)CSTotalprofitPSTwo-PartTariffsp(y)y$/outputunitShouldthemonopolist

setp2=MC?

p1=CS.

PSisprofitfromsales.MC(y)CSPSTwo-PartTariffsp(y)y$/outputunitShouldthemonopolist

setp2=MC?

p1=CS.

PSisprofitfromsales.MC(y)CSAdditionalprofitfromsettingp2=MC.PSTwo-PartTariffsThemonopolistmaximizesitsprofitwhenusingatwo-parttariffbysettingitsperunitpricep2atmarginalcostandsettingitslump-sumfeep1equaltoConsumers’Surplus.Two-PartTariffsAprofit-maximizingtwo-parttariffgivesanefficientmarketoutcomeinwhichthemonopolistobtainsasprofitthetotalofallgains-to-trade.Two-PartTariffsy$/outputunitIftherearemultipleconsumerswithdifferentdemands,thenoptimalpricemaybehigherthanMC.Inthiscase,profit=2T*+(p*-MC)(Q1+Q2)maybehigherthan2ABCMCBACQ1Q2P*T*ExamplesofTwo-PartTariffTelephonehook-upfeeMembershipforaclubItisaspecialcaseof2nd-degreepricediscriminationThemoreyoubuy,thelowertheunitprice.Raretoseepuremonopoly,otherfirmsmaycompetebyproducingsimilarproducts.Implications:Themonopoliststillhasmarketpower–demandslopesdownCompetitionfromsimilarproductsdrivesprofittozero.Tominimizecompetition,afirmtriestodifferentiateproduct.MonopolisticCompetition(垄断竞争)MonopolisticCompetition$/outputunityp(y)y*p(y*)AC(y)MonopolisticCompetition$/outputunityMC(y)p(y)MR(y)y*p(y*)AC(y)9、静夜四无无邻，荒居居旧业贫。。。12月-2212月-22Saturday,December24,202210、雨中黄叶叶树，灯下下白头人。。。08:00:3308:00:3308:0012/24/20228:00:33AM11、以我独沈沈久，愧君君相见频。。。12月-2208:00:3308:00Dec-2224-Dec-2212、故人江海海别，几度度隔山川。。。08:00:3308:00:3308:00Saturday,December24,202213、乍见翻疑梦梦，相悲各问问年。。12月-2212月-2208:00:3308:00:33December24,202214、他乡生白发发，旧国见青青山。。24十二月月20228:00:33上午08:00:3312月-2215、比不了得得就不比，，得不到的的就不要。。。。十二月228:00上上午12月-2208:00December24,202216、行动出成成果，工作作出财富。。。2022/12/248:00:3308:00:3324December202217、做做前前，，能能够够环环视视四四周周；；做做时时，，你你只只能能或或者者最最好好沿沿着着以以脚脚为为起起点点的的射射线线向向前前。。。。8:00:33上上午午8:00上上午午08:00:3312月月-229、没没有有失失败败，，只只有有暂暂时时停停止止成成功功！！。。12月月-2212月月-22Saturday,December24,202210、很多事事情努力力了未必必有结果果，但是是不努力力却什么么改变也也没有。。。08:00:3308:00:3308:0012/24/20228:00:33AM11、成功就就是日复复一日那那一点点点小小努努力的积积累。。。12月-2208:00:3308:00Dec-2224-Dec-2212、世间成成事，不不求其绝绝对圆满满，留一一份不足足，可得得无限完完美。。。08:00:3308:00:3308:00Saturday,December24,202213、不知香积积寺，数里里入云峰。。。12月-2212月-2208:00:3308:00:33December24,202214、意志坚强强的人能把把世界放在在手中像泥泥块一样任任意揉捏。。24十二二月20228:00:33上上午08:00:3312月-2215、楚楚塞塞三三湘湘接接，，荆