Chapter4Pricediscrimination ECNUOrientalRealEstateCollege 4 1Definition Aprevalentmarketingskillandeconomicphenomena preferentialpriceorquantitydiscount eg Sometimespeoplewillthinkthatiffirmschargedifferentpriceondifferentconsumersforthesamegoods itmeanspricediscrimination Butthisunderstandingisincomplete Inmuchcase discretepricemaybeonlyreflecttrafficcostandsalescostfee Andincertaincase universalpricemeansdiscriminationonthecontrary fixedfeeinbuseg Pricediscriminationmeansonefirmsalestheidenticalgoodstodifferentconsumerswithdifferentnetprice Philips 1983 Netprice subtractproductdifferencefromgoodsprice Ifpricedifferentiationjustreflectsthecostdifferenceofsupplyingtodifferentconsumers wedeempricediscriminationdoesn texist Ratiotest Harrypotter inpainlypackededitionvs deluxeedition eg Atthesametime wecan tsayprovidingdifferentqualitygoodstodifferentconsumersmeansnodiscrimination Reasonofprovidingserviceindifferentquality suchasclassedcabininaircraftsandtrains partlyistogetconsumerssurplusbysegmentingconsumersintodifferentgroupsTheconceptof identical goods BMWinUSAisthesametoinGerman Generalequilibriumtheoristmaypointoutwithsomeexcuse goodsdeliveredindifferenttime differentlocationanddifferentstateordifferentqualityisdifferentgoods soscopeofpurepricediscriminationisverylimited Conditionsofpricediscrimination 1 firmsmusthasmarketpower Weoftenconfineitinmonopolyoroligopolymarket onlywhenfirmscanpricehigherthanmarginalcost cantheychargedifferentpriceondifferentconsumers LocayandRodriguez 1992 competitivefirmsispossibletopracticepricediscrimination ifconsumerspurchaseingroupunit 2 theabilityofeffectivemarketsegmentation 3 ensureofnoarbitrage Marketsegmentation Canwefindarightwaytoconductmarketsegmentation theresultmustberelatedtopriceelasticityandWTP willingtopay statusgenderageLocationtimeusePurchasingamount Kindsofarbitrages Possibilityofpricediscriminationisrelatedwithpossibilityofarbitrage Onekindofarbitrageisrelatedwithtransferabilityofgoods Iftransactioncostislow pricediscriminationwillencounterarbitrage namelylow priceconsumerswillbuyforresellingtohigh priceconsumers Transactioncostprovidesonecluetofeasibilityofpricediscrimination Absolutearbitrageornoarbitrageisonlytwoextremecase Generally somelimitedarbitragewilloccurs itdependsonrelativecostandincome Theotherkindofarbitrageisrelatedwithtransferabilityofdifferentconsumepackagesorbundlesprovidedtoconsumers Thatnotmeansphysicaltransferofgoodsamongconsumers Thatmeansfirmstrytomakeeverybuyerreallyselectconsumepackagedesignedforhim notforothers Incentivecompatibilityandself selection Influenceofarbitrage Influenceoftwokindsofarbitrageisdifferent Transferabilityofgoodsisinclinedtopreventdiscrimination Transferabilityofdemandmaycausefirmsincreasediscrimination Threekindsofpricediscrimination Perfectpricediscrimination suppliersgetallconsumersurplusinconditionofholdingperfectinformationofwillingpayment Second degreepricediscrimination suppliersextractconsumersurplusincompletelyusingself selectionwheninformationofindividualpreferenceisincomplete Third degreepricediscrimination Marketsegmentationusingdirectinformationaboutdemandsuchasage professionandlocationetc andsetdifferentpriceforeachgroup 4 2Perfectpricediscrimination simplestcase singleconsumer orsomeidenticalconsumers hasoneunitofdemand Monopolymakepriceequaltoreserveprice gettingallconsumersurplus Aclassicalexample adoctorisalittlevillagesimilarwitheverybodyinthereandtheireconomicinformation Heestimateshowmucheveryoneiswillingtopayforandthenchargeforthatamount Anothercase airlinecompanypayforeachaircraftindifferentprice 2 Complexcase assumption nconsumersholdthesamedemandcurve andmonopolyknowaboutit q D p n soD p nqTgrossofconsumers paymentTwopricingprojects linearpricingandtwoparttariffLinearpricing T pqTwoparttariff T A pq Profitmaximization Inlinearpricing monopolyprice p Twoparttariff setasnetconsumersurplusincompetitivepricep set licensefee A sopricingprojectasbelowT q Profitcompare Monopolypricing Twoparttariff 0 Ifq 0 Ifq 0 Profitcompare D MC A B C ABC Obviously alltheconsumersurplusisgrabbedintwoparttariff 3 Universalcase Assumption consumersholddifferentdemandcurves andmonopolyknowaboutthem Optimalproject setp andaskeachconsumerpayitsnetsurplusas licensefee namelyProblemofinformationrevealwhenconsumerhasunitdemandandsupplieronlyknowdistributionofestimationamongthembutnoabouteveryone sestimation itwillsetsingleprice meansnopricediscrimination HowtomakePerfectpricediscrimination Infactit saquestionofinformationemergingCompretivelyusecouponoraccumulatedconsumingvolumesAuctionorbidPricinginbindBargainingdirectly 優惠券的使用 JournalofMarketingResearch 1978 表中條目是有使用優惠券傾向的全職主婦購買商品的比例括號中的數字表示所表示比例的抽取樣本中人數 4 3Third degreepricediscrimination Multi market assumption Monopolycansegmentconsumersinsomegroupsaccordingtosomeexogenousinformation andknowabouteachoftheirdemandcurves Noarbitrageamonggroups andmonopolycan tpractisepricediscriminationinonegroup Aspecialexampleofmultipleproductsmonopolypricing independentdemandandinterdependentcost Howtopreventarbitrage 持卡 憑證擔保 轉售限制 尤其是對于中間商 摻雜交易費用合約垂直一體化專欄 航空公司如何防止套利 Profitmaximization GeneraldemandProfitfunctionAccordingtoInverseelasticityrule Lernerindex ineverymarketshouldexistsOptimalpricingmeanssettingcomparativelyhighpriceinmarketwithlowerelasticity MR1 D1 MR2 D2 MC p1 p2 Q1 Q2 Welfarecompare CompareitwiththeresultofuniformpricingAssumethatscalerewardfixed Cisconstant Profitandsurplus Incaseofpricediscrimination priceinmarketiispi profitasbelowGeneralconsumersurplusisIncaseofuniformpricing priceis salesamountinmarketIis profitasbelowGeneralconsumersurplusis Differenceonwelfare GeneraldifferenceequalstochangeofsurplusplusprofitTosetuplimitanddownlimit makeFunctionofNSWisconvexfunctionofmarketprice andS p D p accordingtoLagrangemediantheory wecangetSo ifpricediscriminationcannotincreasesalesvolume welfarewillbereduced Thatisthenecessaryconditionofexistenceofpricediscriminationinthesocialangle Conclusion Generally thewelfareeffectofthethird degreepricediscriminationisuncertain Itdependsonthecomparebetweenlossoflow elasticitycomparisonandgainofhigh elasticityconsumersandsuppliers Oneofthecentralquestioninpolicyisitsinfluencetoincomedistribution Pricediscriminationtransfersbenefitoflow elasticityconsumerspartlytohigh elasticityconsumersandsuppliers Itmaybenotappropriate butasweknow low elasticityconsumersaregenerally notalways richergroup 三級價格歧視實例1 三級價格歧視實例2 迪斯尼世界門票價格 2006 4 4Second degreepricediscrimination Assumption consumerdemandisheterogeneous Ifmonopolyknowabouttastesofallconsumers itcanmakeperfectpricediscriminationthroughprovidingpersonalconsumepackagesorbundles Butmonopolygenerallycannotclassifyconsumersaccordingtosomeexplicitinformation anditcanprovideamenuforselection Thenpossibilityofarbitragemustbeconsidered namelyconsumersbelongingtoonegroupmaychooseconsumepackagedesignedforothergroups Therestrictionofself selectionorincentive compatible 4 4 1indirectpricediscriminationbasedontime 航空公司基于訂票時間的價格歧視 p 起飛時間 預售時間 票價與提前訂票時間的關系 提前訂票時間 2 3天 4 4 2Indirectpricediscriminationbasedonquality ProductlineswithdifferentqualitystatusDifferentkindsofconsumers highvaluetype lowvaluetypeCommonstrategy harmed goods IBM Sony Intel p Productstatus 400 350 300 600 486SX 486 質量歧視的三個決策 廠商應該確定幾種不同的等級 實踐表明 三個而不是兩個等級是最優的 各個等級水平如何選擇 如何為每個等級的產品制定相應的價格 參與約束 激勵相容約束 例 參考價格對高價位產品的影響 4 4 3Indirectpricediscriminationbasedonquantity quantitydiscount taxifeeelectricpowerusePackagestrategy quantity priceportfolio 英國移動通信公司的二部定價套餐 此外還有 移動的動感地帶短信套餐等 4 5Comparisionamongseveralmethodsinnonlinearpricing Two parttariff T q A pq providesamenuofconsumebundlesinaline Generallythelinedoesnotpassorigin Simplicityisitsprimaryattraction andsometimesitdependsonpossibilityoflimitedarbitrage Fullarbitrageisprevented namelyonlyonebuyerpaysforfixedfeeA andthenresalegoodstootherconsumers Notice actuallytwo parttariffcorrespondstoquantitydiscount averagepricedecreasewithincreaseofconsumequantity Profitandwelfare Assumption consumersreferenceasbelowU V 0 0 V q 0 V q 0 isaconstantoftaste differentinperson V isuniformtoeveryone Alsothesecanbeexplainedinthesamepreferenceofconsumersbutwithdifferentincomelevel Compareamongcaseofperfectdiscrimination monopolypricingandtwo parttariff V q TiftheypayTandconsumeq 0iftheydonotbuy Asimplemodel Twokindsofconsumers proportionoftasteparameterbeing 1is proportionoftasteparameterbeing 2is1 Assumethat 2 1 monopolyproduceinfixedcostc andc 1 2 forsimplicity assumesoV q 1 q Utilityfunction Notice fixedcostonlyinfluencethedecisionofbuyingornot Onceconsumersdecidetobuy itisoutofconsider Consumerutilitymaximization U iV q pqFirst ordercondition iV q pAccordingtoassumptionbefore i 1 q pSo demandfunctioniseducedasq Di p 1 p iNetconsumersurplusis Generaldemandfunction Inthiscase consumersurplusisNoticethat and 2typeconsumersalwaysholdhighersurplus Make asharmonicmeanof 1and 2Thengeneraldemandinpricepis 2 1 p P1 c D1 D2 S2 p S1 p Case1 perfectpricediscrimination Assumethatmonopolycanobserve idirectly Thenitcansetmarginalpriceasp1 c andsetpersonalfixedfeeManufacturer smonopolisticprofitisLeavedistributionquestionoutofaccount welfarehereisoptimal Case2 Monopolypricing Assumethatconsumershavecompletearbitrage sothatmonopolycanonlysetuniformprice T q pqProfitis p c D p andD p 1 p MonopolypriceisMonopolisticprofitisHereweassumethatmonopolydecidestoprovidegoodstotwokindsofconsumers Itneed c 2 2 1 or islargeenough Case3 Two parttariff Assumealsothatmonopolyprovidesgoodstotwokindsofconsumers Setmarginalpricep Maximalfixedfeethatcanmake 1typeconsumersbuygoodsisA S1 p Then 2typeconsumerswillpurchase becauseSoprofitfunctionofmonopolyisPriceofprofitmaximizationisSimply wecanseethatprofitoftwo parttariffisasgoodasinlinearpricingatleast thelatecanbeseenasthespecialcaseoftheformer Comparisoninwelfareeffect It ssimpletojudgethatAndalso inthecaseofsupplyingtwokindsofconsumersatthesametime marginaloftwo parttariffisbetweencompetitivepriceandmonopolyprice namelyNotice welfareundertwo parttariffishigherthaninlinearpricing becausemarginalpricedecreasingwillbringpurchasingmorebytwokindsofconsumers sodistortionisreduced Tomonopoly itcanmakeuplossbyfixedfeewhendecreasingprice Sofixedfeewillinducemonopolydecreasepricesothatwelfareisgained Conclusion Wecanmakeamorecomplexprojecttogetmoreprofitthroughcompletenonlinearpricing processomitted Conclusion1 low demandconsumersdonotgetnetsurplus whilehigh demandconsumerscangetpositivenetsurplus Conclusion2 effectiverestrictiontopersonalarbitragewillpreventhigh demandconsumersbuylow demandbundles Conclusion3 high demandconsumersbuysociallyoptimalquantity andlow demandconsumersbuyquantitylowerthanoptimalquantity 4 6Qualitydiscrimination Monopolycanalsopractisediscriminationthroughprovidingdifferentqualitygoodstodifferenttastyconsumers Itisverysimilartoquantitydiscrimination Assumethatconsumershaveunitd