昆明理工大學(xué)MBA中級(jí)微觀第章講義壟斷行為

ChapterTwenty-FiveMonopolyBehavior壟斷行為HowShouldaMonopolyPrice?Sofaramonopolyhasbeenthoughtofasafirmwhichhastosellitsproductatthesamepricetoeverycustomer.Thisisuniformpricing.Canprice-discrimination（差別定價(jià)）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.üytThird-degreePriceDiscriminationüytThemarginalrevenuecommontobothmarketsequalsthemarginalproductioncostifprofitistobemaximized.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$/outputunitIftherearemultipleconsumerswithdifferentdemands,thenoptimalpricemaybehigherthanMC.Inthiscase,profit=2T*+(p*-MC)(Q1+Q2)maybehigherthan2ABCMCBACQ1Q2P*T*ExamplesofTwo-PartTariffTelephonehook-upfeeMembershipforaclubItisaspecialcaseof2nd-degreepricediscriminationThemoreyoubuy,thelowertheunitprice.Raretoseepuremonopoly,otherfirmsmaycompetebyproducingsimilarproducts.Implications:Themonopoliststillhasmarketpower–demandslopesdownCompetitionfromsimilarproductsdrivesprofittozero.Tominimizecompetition,afirmtriestodifferentiateproduct.MonopolisticCompetition(壟斷競(jìng)爭(zhēng))MonopolisticCompetition$/outputunityp(y)y*p(y*)AC(y)MonopolisticCompetition$/outputunityMC(y)p(y)MR(y)y*p(y*)AC(y)9、靜夜四無(wú)無(wú)鄰，荒居居舊業(yè)貧。。。12月-2212月-22Saturday,December24,202210、雨中黃葉葉樹，燈下下白頭人。。。08:00:3308:00:3308:0012/24/20228:00:33AM11、以我獨(dú)沈沈久，愧君君相見頻。。。12月-2208:00:3308:00Dec-2224-Dec-2212、故人江海海別，幾度度隔山川。。。08:00:3308:00:3308:00Saturday,December24,202213、乍見翻疑夢(mèng)夢(mèng)，相悲各問問年。。12月-2212月-2208:00:3308:00:33December24,202214、他鄉(xiāng)生白發(fā)發(fā)，舊國(guó)見青青山。。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、行動(dòng)出成成果，工作作出財(cái)富。。。2022/12/248:00:3308:00:3324December202217、做做前前，，能能夠夠環(huán)環(huán)視視四四周周；；做做時(shí)時(shí)，，你你只只能能或或者者最最好好沿沿著著以以腳腳為為起起點(diǎn)點(diǎn)的的射射線線向向前前。。。。8:00:33上上午午8:00上上午午08:00:3312月月-229、沒沒有有失失敗敗，，只只有有暫暫時(shí)時(shí)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結(jié)果果，但是是不努力力卻什么么改變也也沒有。。。08:00:3308:00:3308:0012/24/20228:00:33AM11、成功就就是日復(fù)復(fù)一日那那一點(diǎn)點(diǎn)點(diǎn)小小努努力的積積累。。。12月-2208:00:3308:00Dec-2224-Dec-2212、世間成成事，不不求其絕絕對(duì)圓滿滿，留一一份不足足，可得得無(wú)限完完美。。。08:00:3308:00:3308:00Saturday,December24,202213、不知香積積寺，數(shù)里里入云峰。。。12月-2212月-2208:00:3308:00:33December24,202214、意志堅(jiān)強(qiáng)強(qiáng)的人能把把世界放在在手中像泥泥塊一樣任任意揉捏。。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，，荊