管經(jīng)-管理經(jīng)濟(jì)學(xué)課件

第12章：具有市場(chǎng)力企業(yè)的決策LearningObjectivesDefinemarketpoweranddescribemeasurementofmarketpowerExplainwhyentrybarriersarenecessaryforlongrunmarketpoweranddiscussmajortypesofentrybarriersFindtheprofit‐maximizingoutput,price,andinputusageforamonopolistandmonopolisticcompetitorEmployempiricallyestimatedorforecasteddemand,averagevariablecost,andmarginalcosttocalculateprofit‐maximizingoutputandpriceformonopolisticormonopolisticallycompetitivefirmsSelectproductionlevelsatmultipleplantstominimizethetotalcostofproducingagiventotaloutputforafirm壟斷Monopoly市場(chǎng)只有一個(gè)企業(yè)生產(chǎn)和銷售沒有相近替代品的差異化產(chǎn)品或服務(wù)新企業(yè)被阻止進(jìn)入市場(chǎng)TheBiggestContract

intheentirehistoryofGazpromThe30-yearcontractstipulatesthat38billioncubicmetersofRussiangaswillbeannuallysuppliedtoChinaTheAntitrustCaseAgainstMicrosoftSoftwarepioneer,monopolist,orboth?IsGoogleaMonopoly?

In2011,Microsoftfiledacomplaintwith

theEuropeanCommissionthatGoogle

wasusingitsdominantpositionasan

Internetsearchenginetocreatean

effectivemonopolybyexcludingcompetitors.Googlearguesthatitsdominantmarketshareisduetothehigherqualityofitssearchengine,notanyattemptsthecompanyhasmadetoreducetheaccessofothersearchenginestoonlinecontent.市場(chǎng)力MarketPower企業(yè)提高價(jià)格而不失去全部銷售量的能力任何面臨向下傾斜需求曲線的企業(yè)都具有一定的市場(chǎng)力使得企業(yè)能夠定價(jià)高于平均成本并且獲取經(jīng)濟(jì)利潤(rùn)

（如果需求和成本情況允許）市場(chǎng)界定市場(chǎng)界定：在一定的地理區(qū)域內(nèi)，識(shí)別所有的競(jìng)爭(zhēng)廠商和競(jìng)爭(zhēng)產(chǎn)品及服務(wù)。一個(gè)市場(chǎng)由所有生產(chǎn)相似產(chǎn)品的廠商構(gòu)成。一個(gè)正確定義的市場(chǎng)，必須能夠包括所有消費(fèi)者認(rèn)同可以相互替代的產(chǎn)品和服務(wù)。可以通過價(jià)格上升的影響來(lái)界定相近替代品：如果對(duì)市場(chǎng)的定義十分狹隘，那么價(jià)格的上升會(huì)使廠商的銷量和利潤(rùn)大幅下降，說明市場(chǎng)界定過??；擴(kuò)大市場(chǎng)范圍，直到利潤(rùn)上升為止。如可口可樂的市場(chǎng)（DrPepperin1986）市場(chǎng)力的度量市場(chǎng)力的程度與需求價(jià)格彈性反向相關(guān)企業(yè)需求越缺乏彈性，企業(yè)的市場(chǎng)力就越大企業(yè)產(chǎn)品越缺乏相應(yīng)的替代品，需求價(jià)格彈性（絕對(duì)值）越小，企業(yè)的市場(chǎng)力越大當(dāng)完全彈性需求（水平需求）時(shí)，企業(yè)沒有市場(chǎng)力市場(chǎng)力的度量勒納指數(shù)（Lernerindex）估計(jì)價(jià)格水平與完全競(jìng)爭(zhēng)條件下價(jià)格的偏離范圍

：市場(chǎng)力的度量勒納指數(shù)完全競(jìng)爭(zhēng)條件下等于零隨著市場(chǎng)力水平的提高而增加也等于

–1/E，表明指數(shù)（市場(chǎng)力）與需求價(jià)格彈性反向相關(guān)需求價(jià)格彈性（絕對(duì)值）越小，指數(shù)越大，市場(chǎng)力水平也越高市場(chǎng)力的度量如果消費(fèi)者認(rèn)為兩種產(chǎn)品是可以替代的，那么需求的交叉價(jià)格彈性

(EXY)

為正產(chǎn)品的交叉價(jià)格彈性越高，兩種產(chǎn)品的替代性越強(qiáng)，生產(chǎn)這兩種產(chǎn)品的公司擁有的市場(chǎng)力就越弱集中度的衡量（赫芬達(dá)爾-赫希曼指數(shù)）TheDepartmentofJusticeandtheFederalTradeCommissionMergerGuidelinesMEASUREOFCONCENTRATION(Herfindahl-HirschmanIndex,HHI)1firm,100%marketshare(amonopoly):HHI=1002=10,0002firms,eachwitha50%marketshare:HHI=502+502=5,0004firms,withmarketsharesof30%,30%,20%,and20%:

HHI=302+302+202+202=2,60010firms,eachwithmarketsharesof10%:HHI=10(102)=1,000合并標(biāo)準(zhǔn)MERGERSTANDARDS合并后的HHI指數(shù)低于1,000.該市場(chǎng)不是集中的,因此合并不會(huì)遭到挑戰(zhàn)；合并后的HHI指數(shù)介于1,000和1,800之間.這些市場(chǎng)的集中度不高，如果合并使HHI指數(shù)的提高低于100，這一合并不會(huì)受到挑戰(zhàn)；如果合并使HHI指數(shù)提高大于100，則可能受到挑戰(zhàn).合并后HHI指數(shù)高于1,800.這些市場(chǎng)是高度集中的。使HHI指數(shù)提高低于50的合并，不會(huì)受到挑戰(zhàn)；提高幅度在50到100之間的合并可能受到挑戰(zhàn)；提高幅度超過100的合并必然受到挑戰(zhàn).1992年兼并指南下的兼并安全港安全不安全不安全安全安全不安全安全安全安全兼并后的HHIHHI增長(zhǎng)1800100010050市場(chǎng)力的決定因素新廠商進(jìn)入市場(chǎng)，會(huì)增加替代品的數(shù)量，從而削弱目前企業(yè)的市場(chǎng)力只有當(dāng)存在比較強(qiáng)的進(jìn)入壁壘時(shí)，市場(chǎng)中的廠商才能擁有較高水平的市場(chǎng)力強(qiáng)進(jìn)入壁壘阻礙了新廠商的進(jìn)入，從而保證了市場(chǎng)現(xiàn)存廠商的利潤(rùn)常見的進(jìn)入壁壘政府設(shè)置的壁壘特許權(quán)或執(zhí)照（電力、自來(lái)水、出租車等）專利和版權(quán)等自然壟斷NaturalMonopoly（或者，規(guī)模經(jīng)濟(jì)Economiesofscale）在與產(chǎn)品需求相關(guān)的產(chǎn)量范圍內(nèi)，如果廠商的長(zhǎng)期平均成本曲線是呈下降趨勢(shì)的，那么會(huì)產(chǎn)生很強(qiáng)的進(jìn)入壁壘沉沒成本的進(jìn)入壁壘W(wǎng)ithanaturalmonopoly,theaveragetotalcostcurve

isstillfallingwhenitcrosses

thedemandcurve(pointA).Ifonlyonefirmisproducing

electricpowerinthemarket,anditproduceswherethe

averagecostcurve

intersectsthedemandcurve,averagetotalcostwillequal

$0.04perkilowatt-hourof

electricityproduced.Ifthemarketisdivided

betweentwofirms,eachproducing15billion

kilowatt-hours,theaveragecostofproducingelectricityrisesto$0.06perkilowatt-hour(pointB).Inthiscase,ifonefirmexpandsproduction,itcanmovedowntheaveragetotalcostcurve,loweritsprice,anddrivetheotherfirmoutofbusiness.NaturalmonopolyAsituationinwhicheconomiesofscalearesolargethatonefirmcansupplytheentiremarketataloweraveragetotalcostthancantwoormorefirms.常見的進(jìn)入壁壘品牌效應(yīng)Brandloyalties消費(fèi)者對(duì)現(xiàn)有企業(yè)的忠誠(chéng)度，使那些新進(jìn)入市場(chǎng)的企業(yè)很難發(fā)現(xiàn)足夠的買者，因而無(wú)法進(jìn)入Realemon濃縮檸檬汁要素壁壘Inputbarriers一個(gè)企業(yè)控制了某一生產(chǎn)過程的關(guān)鍵投入要素美國(guó)鋁業(yè)（Alcoa），或者資本、渠道等iOSAdiamondisforeverDeBeerspromotedthesentimentalvalueofdiamondsasawaytomaintainitspositioninthediamondmarket.TheEndoftheChristmasPlantMonopolyFormanyyears,thePaulEckeRanchinEncinitas,

Californiahadamonopolyonpoinsettias,whose

strikingredandgreencolorsthatblossominthe

wintermakethemidealforChristmasdecorating.Afterdiscoveringanewtechniqueforgrowingthe

wildflowerthatwaskeptsecretfordecades,the

Eckefamilywasabletomaintainamonopolyonits

commercialproductionwithoutacquiringapatent,untilauniversityresearcherdiscoveredthe

techniqueandpublisheditinanacademicjournal.Asaresult,manynewfirmsquicklyenteredthe

industryandthepriceofpoinsettiasplummeted.常見的進(jìn)入壁壘網(wǎng)絡(luò)外延Networkexternalities近20年計(jì)算機(jī)技術(shù)、互聯(lián)網(wǎng)、新軟件發(fā)展迅猛信息產(chǎn)品特點(diǎn)：無(wú)成本復(fù)制、快速擴(kuò)散、不變質(zhì)某種產(chǎn)品或服務(wù)的效用會(huì)隨著使用人數(shù)的增加而增加，該產(chǎn)品或服務(wù)在消費(fèi)中存在網(wǎng)絡(luò)效應(yīng)例子：微信，京東，大眾點(diǎn)評(píng)網(wǎng)，標(biāo)準(zhǔn)，信用卡，DVD與碟片，蘋果硬件、系統(tǒng)與軟件，維護(hù)等一旦企業(yè)建立了巨大的消費(fèi)者網(wǎng)絡(luò)，新企業(yè)就難以進(jìn)入市場(chǎng)，首先建立用戶基礎(chǔ)的企業(yè)具有先入優(yōu)勢(shì)POSITIVENETWORKEXTERNALITYinwhichaconsumerwishestopossessagoodinpartbecauseothersdoBandwagonEffect攀比效應(yīng)Withapositivenetworkexternality,thequantityofagoodthatanindividualdemandsgrowsinresponsetothegrowthofpurchasesbyotherindividuals.Here,asthepriceoftheproductfallsfrom$30to$20,thebandwagoneffectcausesthedemandforthegoodtoshifttotheright,fromD40toD80.NEGATIVENETWORKEXTERNALITYinwhichaconsumerwishestoownanexclusiveoruniquegood.SnobEffect虛榮效應(yīng)Thesnobeffectisanegativenetworkexternalityinwhichthequantityofagoodthatanindividualdemandsfallsinresponsetothegrowthofpurchasesbyotherindividuals.Here,asthepricefallsfrom$30,000to$15,000andmorepeoplebuythegood,thesnobeffectcausesthedemandforthegoodtoshifttotheleft,fromD2toD6.Althoughnotfirsttomarket,Bicultimatelywasmoresuccessfulthanthefirmthatpioneeredballpointpens.(vs.Reynolds)IsBeingtheFirstFirmintheMarketaKeytoSuccess?Thefirmsthatwerefirsttointroduceaproductultimatelylostouttoerswhodidabetterjobofprovidingconsumerswithproductsthatweremorereliable,lessexpensive,moreconvenient,orotherwiseprovidedgreatervalue.iPodHPLaserJetP&GPampersIE常見的進(jìn)入壁壘消費(fèi)者鎖定Consumerlock-in如果潛在的進(jìn)入者認(rèn)為昂貴的轉(zhuǎn)換成本使現(xiàn)有消費(fèi)者不會(huì)轉(zhuǎn)向其它品牌時(shí)，他們就被阻止進(jìn)入了轉(zhuǎn)換成本：安裝或入會(huì)費(fèi)；尋找可能替代品及其價(jià)格的成本；學(xué)習(xí)如何使用新的或者不同產(chǎn)品或服務(wù)的成本。高轉(zhuǎn)換成本可能是自然形成的，也可能是企業(yè)戰(zhàn)略性創(chuàng)造的例子：從Office到WPS?從Nikon到Canon？壟斷廠商面臨的需求和邊際收益市場(chǎng)需求曲線就是壟斷企業(yè)的需求曲線壟斷者想要售出更多的產(chǎn)品，就必須降低價(jià)格（統(tǒng)一定價(jià)時(shí)）除了第一件產(chǎn)品，其余每件產(chǎn)品出售帶來(lái)的邊際收益都低于其價(jià)格當(dāng)MR

為正值(負(fù)值)，需求具有彈性(缺乏彈性)壟斷廠商面臨的需求和邊際收益壟斷下的短期利潤(rùn)最大化(圖12.3)壟斷下的短期利潤(rùn)最大化如果部分需求曲線對(duì)應(yīng)的價(jià)格水平高于平均變動(dòng)成本，壟斷廠商在短期內(nèi)會(huì)進(jìn)行生產(chǎn)通過MR=MC時(shí)的產(chǎn)出量，可以達(dá)到利潤(rùn)最大化，或虧損最小化壟斷下的短期損失最小化(圖12.4)壟斷下的短期利潤(rùn)最大化若P>ATC,企業(yè)獲利若ATC>P>AVC,企業(yè)產(chǎn)生虧損，但短期內(nèi)仍繼續(xù)生產(chǎn)若在任何產(chǎn)出水平需求曲線都低于AVC,企業(yè)會(huì)停止生產(chǎn)，以使虧損的部分只是固定成本不同于完全競(jìng)爭(zhēng)市場(chǎng)，這里AVC不是最小值A(chǔ)VC處于下降階段MaximizingProfit

P(Q)=24-Q

C(Q)=Q2+12

MonopolyExampleInversedemandfunction:Canbeusedtofindthemarginalrevenuefunction:

QuadraticSRcostfunction:Canbeusedtofindthemarginalcostfunction:

Profit-maximizingoutputisobtainedbyproducingQ*:SolvingthisexpressionrevealsQ*=6Theinversedemandfunctionindicatesthatpeoplearewillingtopayp=$18for6unitsofoutput.AppleintroduceditsiPodin2001DataMarginalcost=$200Fixedcost=$736millionDemandfunction:P=600-25Q(inmillion)Questions:Whatwereitsprofitmaximizingpriceandquantity,profit,andLernerIndex,priceelasticity?AnswerAC=200+736/QMR=600-50QQ=8million;P=$400Profit=(P-AC)Q=[400-(200+736/8)]*8=$864millionLernerIndex=[P-MC]/P=[400-200]/400=1/2PriceElasticity=-1/LI=-2Graph壟斷下的長(zhǎng)期利潤(rùn)最大化(圖12.5)壟斷下的長(zhǎng)期利潤(rùn)最大化壟斷廠商通過選擇一個(gè)能夠使MR=LMC的產(chǎn)出水平只要

PLAC，企業(yè)就實(shí)現(xiàn)了利潤(rùn)最大化如果

P<LAC，企業(yè)就退出市場(chǎng)壟斷廠商將調(diào)整企業(yè)規(guī)模達(dá)到最優(yōu)水平在利潤(rùn)最大化對(duì)應(yīng)的產(chǎn)出水平上，短期平均成本曲線正好與長(zhǎng)期成本曲線相切SHIFTSINDEMANDShiftingthedemandcurveshowsthatamonopolisticmarkethasnosupplycurve—i.e.,thereisnoone-to-onerelationshipbetweenpriceandquantityproduced.In(a),thedemandcurveD1shiftstonewdemandcurveD2.ButthenewmarginalrevenuecurveMR2intersectsmarginalcostatthesamepointastheoldmarginalrevenuecurveMR1.Theprofit-maximizingoutputthereforeremainsthesame,althoughpricefallsfromP1toP2.In(b),thenewmarginalrevenuecurveMR2intersectsmarginalcostatahigheroutputlevelQ2.Butbecausedemandisnowmoreelastic,priceremainsthesame.利潤(rùn)最大化決策的一般原則企業(yè)應(yīng)該生產(chǎn)還是關(guān)門？對(duì)應(yīng)某一產(chǎn)量水平，只要市場(chǎng)價(jià)格超過平均可變成本，就要生產(chǎn)：P>=AVC，否則關(guān)門如果生產(chǎn)，應(yīng)該生產(chǎn)多少，價(jià)格為多少？為了保證利潤(rùn)最大化，在邊際收益等于邊際成本（MR=MC）點(diǎn)上決定產(chǎn)量，并以此產(chǎn)量按需求曲線決定價(jià)格ReplyfromProf.Christopher利潤(rùn)最大化產(chǎn)量與價(jià)格決策的實(shí)施Step1:估計(jì)需求函數(shù)廣義需求函數(shù)估計(jì)（運(yùn)用第七章的統(tǒng)計(jì)技術(shù)）用預(yù)測(cè)的外生變量的未來(lái)值代入估計(jì)的需求函數(shù)，得到利潤(rùn)最大化產(chǎn)量與價(jià)格決策的實(shí)施Step2:求需求函數(shù)的反函數(shù)解出P利潤(rùn)最大化產(chǎn)量與價(jià)格決策的實(shí)施Step3:求邊際收益當(dāng)需求函數(shù)表示為

P=A+BQ，邊際收益函數(shù)寫為利潤(rùn)最大化產(chǎn)量與價(jià)格決策的實(shí)施Step4:估計(jì)AVC&SMC運(yùn)用第十章的統(tǒng)計(jì)技術(shù)AVC=a+bQ+cQ2SMC=a+2bQ+3cQ2Step5:找出

MR=SMC的產(chǎn)出水平令邊際收益等于邊際成本，解出

Q*兩個(gè)解中大的一個(gè)就是利潤(rùn)最大化的產(chǎn)出量Step6:找出最優(yōu)價(jià)格把

Q*

代入反需求函數(shù)，得P*=A+BQ*只有PAVC時(shí)，所得出的

Q*&P*

才是最優(yōu)的利潤(rùn)最大化產(chǎn)量與價(jià)格決策的實(shí)施利潤(rùn)最大化產(chǎn)量與價(jià)格決策的實(shí)施Step7:檢驗(yàn)關(guān)門法則把

Q*

代入到估計(jì)的AVC方程若

P*

AVC*，產(chǎn)出為Q*

且售價(jià)為

P*

若P*

<AVC*，短期關(guān)門AVC*=a+bQ*+cQ*2利潤(rùn)最大化產(chǎn)量與價(jià)格決策的實(shí)施Step8:計(jì)算利潤(rùn)或虧損Profit=TR–TC

=PxQ*-AVCxQ*-TFC=(P–AVC)Q*-TFC若P<AVC，壟斷企業(yè)關(guān)門并且利潤(rùn)為-TFCAztecElectronics的利潤(rùn)最大化因?yàn)閾碛袑＠?，Aztec擁有市場(chǎng)力銷售高級(jí)無(wú)線立體聲耳機(jī)，市場(chǎng)需求：固定成本$270,000，平均變動(dòng)成本：

AVC=28–0.005Q+0.000001Q2預(yù)計(jì)2015年：M=$45,000,PR=$800企業(yè)的利潤(rùn)最大化決策是什么？AztecElectronics的利潤(rùn)最大化估計(jì)需求和邊際收益函數(shù)AztecElectronics的利潤(rùn)最大化求反需求函數(shù)AztecElectronics的利潤(rùn)最大化確定邊際收益函數(shù)P=100–0.002QMR=100–0.004QAztecElectronics的需求和邊際收益AztecElectronics的利潤(rùn)最大化估計(jì)平均變動(dòng)成本函數(shù)和邊際成本函數(shù)estimatedAVCequation:AVC=28–0.005Q+0.000001Q2Then,SMC=28–(2x0.005)Q+(3x0.000001)Q2=28–0.01Q+0.000003Q2AztecElectronics的利潤(rùn)最大化確定產(chǎn)量令

MR=MC

并求解

Q*100–0.004Q=28–0.01Q+0.000003Q20=(28–100)+(-0.01+0.004)Q+0.000003Q2=-72–0.006Q+0.000003Q2AztecElectronics的利潤(rùn)最大化確定產(chǎn)量用二次方程公式解出

Q*AztecElectronics的利潤(rùn)最大化確定價(jià)格把

Q*

代入到反需求函數(shù)P*=100–0.002(6,000)=$88AztecElectronics的利潤(rùn)最大化關(guān)門決策計(jì)算6,000單位時(shí)的

AVC:AVC*=28-0.005(6,000)+0.000001(6,000)2=$34BecauseP=$88>$34=ATC,AztecshouldproduceratherthanshutdownAztecElectronics的利潤(rùn)最大化計(jì)算總利潤(rùn)π

=TR–TVC–TFC=

(P*

xQ*)–(AVC*

xQ*)–TFC=($88x6,000)–($34x6,000)-$270,000=$528,000-$204,000-$270,000=$54,000若人均收入下降，導(dǎo)致企業(yè)需求下降：P=80-0.002Q，成本不變，企業(yè)如何決策？AztecElectronics的利潤(rùn)最大化ELASTICITYOFDEMANDANDPRICEMARKUPTheRuleofThumbforPricingThemarkup(P?MC)/Pisequaltominustheinverseoftheelasticityofdemand.Ifthefirm’sdemandiselastic,asin(a),themarkupissmallandthefirmhaslittlemonopolypower.Theoppositeistrueifdemandisrelativelyinelastic,asin(b).

MARKUPPRICING:SUPERMARKETSTODESIGNERJEANSAlthoughtheelasticityofmarketdemandforfoodis

small(about?1),nosinglesupermarketcanraiseits

pricesverymuchwithoutlosingcustomerstoother

stores.Theelasticityofdemandforanyonesupermarketis

oftenaslargeas?10.WefindP=MC/(1?0.1)=

MC/(0.9)=(1.11)MC.Themanagerofatypicalsupermarketshouldsetpricesabout11percentabovemarginalcost.Smallconveniencestorestypicallychargehigherpricesbecauseitscustomersaregenerallylesspricesensitive.Becausetheelasticityofdemandforaconveniencestoreisabout?5,themarkupequationimpliesthatitspricesshouldbeabout25percentabovemarginalcost.Withdesignerjeans,demandelasticitiesintherangeof?2to?3aretypical.Thismeansthatpriceshouldbe50to100percenthigherthanmarginalcost.壟斷的福利代價(jià)與競(jìng)爭(zhēng)企業(yè)相比，壟斷者收取高于邊際成本的價(jià)格。從消費(fèi)者的立場(chǎng)看，高價(jià)格使壟斷不合意

對(duì)企業(yè)擁有者來(lái)說，高價(jià)格使壟斷非常合意壟斷會(huì)降低經(jīng)濟(jì)效率嗎?完全競(jìng)爭(zhēng)與壟斷的比較ComparingMonopolyandPerfectCompetitionEquilibriuminaperfectlycompetitivemarketresultsinthegreatestamountofeconomicsurplus,ortotalbenefittosociety,fromtheproductionofagoodorservice.Amonopolywillproducelessandchargeahigherpricethanwouldaperfectlycompetitiveindustryproducingthesamegood.WhatHappensIfaPerfectlyCompetitiveIndustryesaMonopoly?Inpanel(a),themarketfortabletcomputersisperfectlycompetitive,andpriceandquantityaredeterminedbytheintersectionofthedemandandsupplycurves.Inpanel(b),theperfectlycompetitivetabletcomputerindustryesamonopoly.Asaresult:1.Theindustrysupplycurveesthemonopolist’smarginalcostcurve.2.Themonopolistreducesoutputtowheremarginalrevenueequalsmarginalcost,QM.3.ThemonopolistraisesthepricefromPCtoPM.Amonopolycharges

ahigherprice,PM,andproducesa

smallerquantity,QM,thanaperfectlycompetitiveindustry,whichchargespricePCandproducesQC.Thehigherpricereducesconsumersurplusby

theareaequaltotherectangleAandthetriangleB.Someofthereductioninconsumersurplusiscapturedbythemonopolyasproducersurplus,andsomeesdeadweightloss,whichistheareaequal

totrianglesBandC.TheInefficiencyofMonopoly市場(chǎng)勢(shì)力與技術(shù)進(jìn)步MarketPowerandTechnologicalChangeFirmsareoftenforcedtorelyontheirprofitstofinancetheresearchanddevelopmentneededfornewproducts,butsmallerfirmsdevelopanumberofnewproductsthemselvesaswell.Governmentpolicymakerscontinuetostrugglewiththeissueofwhether,onbalance,largefirmswithmarketpoweraregoodorbadfortheeconomy.AStaticViewofMonopoly:TheMarketforDrugsQuantity0CostsandRevenueDemandMarginalrevenuePriceduringpatentlifeMonopolyquantityPriceafterpatentexpiresMarginalcostCompetitivequantityADynamicViewofMonopoly:TheMarketforPCsMergers:TheTrade-offbetweenMarketPowerandEfficiencyTwofactorscancomplicateregulatinghorizontalmergers:The“market”thatfirmsareinisnotalwaysclear.Thereisthepossibilitythatthenewlymergedfirmmightbemoreefficientthanthemergingfirmswereindividually.Inpractice,thegovernmentdefinestherelevantmarketonthebasisofwhetherthereareclosesubstitutesfortheproductsbeingmadebythemergingfirms.Evenifamergedfirmismoreefficientandhaslowercosts,thatmaynotoffsettheincreasedmarketpowerofthefirmenoughtoincreaseconsumersurplusandeconomicefficiency.HorizontalmergerAmergerbetweenfirmsinthesameindustry.VerticalmergerAmergerbetweenfirmsatdifferentstagesofproduction

ofagood.Thefigureshowstheresultofallthefirmsinaperfectlycompetitiveindustrymergingtoformamonopoly.Ifcostsareunaffectedbythemerger,theresultis:PricerisesfromPCtoPM,quantityfallsfromQCtoQM,consumersurplusdeclines,andalossofeconomicefficiencyresults.If,however,themonopolyhaslowercoststhantheperfectlycompetitivefirms,asshownbythemarginalcostcurveshiftingtoMCafterthemerger,itispossiblethatthepricewillactuallydeclinefromPCtoPMergeandthatoutputwillincreasefromQCtoQMergefollowingthemerger.AMergerThatMakesConsumersBetterOffAlthoughthenewlymergedfirmhasagreatdealofmarketpower,becauseitismoreefficient,consumersarebetteroffandeconomicefficiencyisimproved.政府對(duì)壟斷的干預(yù)法規(guī)管制公有制無(wú)所作為用反托拉斯法增強(qiáng)競(jìng)爭(zhēng)反托拉斯法是一些旨在抑制壟斷勢(shì)力的法規(guī)反托拉斯法允許政府用不同的途徑促進(jìn)競(jìng)爭(zhēng)阻止合并分解公司阻止企業(yè)從事減弱市場(chǎng)競(jìng)爭(zhēng)的活動(dòng)。管制Regulation政府可以管制壟斷者的定價(jià)Governmentmayregulatethepricesthatthemonopolycharges.價(jià)格控制（增加產(chǎn)出/減少供給）Ratecontrol平均成本定價(jià)Average-costpricing邊際成本定價(jià)Marginal-costpricingTHESOCIALCOSTSOFMONOPOLYPOWERIfleftalone,amonopolistproducesQmandchargesPm.WhenthegovernmentimposesapriceceilingofP1thefirm’saverageandmarginalrevenueareconstantandequaltoP1foroutputlevelsuptoQ1.Forlargeroutputlevels,theoriginalaverageandmarginalrevenuecurvesapply.Thenewmarginalrevenuecurveis,therefore,thedarkpurpleline,whichintersectsthemarginalcostcurveatQ1.PriceRegulationTHESOCIALCOSTSOFMONOPOLYPOWERWhenpriceisloweredtoPc,atthepointwheremarginalcostintersectsaveragerevenue,outputincreasestoitsmaximumQc.Thisistheoutputthatwouldbeproducedbyacompetitiveindustry.Loweringpricefurther,toP3reducesoutputtoQ3andcausesashortage,

Q’3?Q3.PriceRegulationRegulatingaNaturalMonopolyAnaturalmonopolythat

isnotsubjectto

governmentregulation

willchargeapriceequal

toPMandproduceQM.Ifgovernmentregulators

wanttoachieve

economicefficiency,theywillsettheregulated

priceequaltoPE,andthemonopolywill

produceQE.Unfortunately,PEis

belowaveragecost,andthemonopolywill

sufferaloss,shownbytheshadedrectangle.Becausethemonopolywillnotcontinuetoproduceinthelongrunifitsuffersaloss,governmentregulatorssetapriceequaltoaveragecost,whichisPRinthefigure.Theresultingproduction,QR,willbebelowtheefficientlevel.Localorstateregulatorycommissionsusuallysetthepricesfornaturalmonopolies.規(guī)制Regulation難以有效規(guī)制政府難以獲得壟斷企業(yè)的邊際、平均成本線；定價(jià)不能低到壟斷企業(yè)虧損（p>ac）；在確定價(jià)格下壟斷企業(yè)會(huì)提供次品，以次充好Marginal-CostPricingforaNaturalMonopoly公有制PublicOwnership政府管制的不是由私人企業(yè)經(jīng)營(yíng)的自然壟斷，而是自己經(jīng)營(yíng)自然壟斷。

投票機(jī)制不如利潤(rùn)動(dòng)機(jī)可靠。如美國(guó)公交政府制造競(jìng)爭(zhēng)（招標(biāo)）。無(wú)所作為DoingNothing如果市場(chǎng)失靈的程度遠(yuǎn)遠(yuǎn)小于政治失靈，政府就不再干預(yù)。Governmentcandonothingatallifthemarketfailureisdeemedsmallcomparedtotheimperfectionsofpublicpolicies.美國(guó)經(jīng)濟(jì)“市場(chǎng)失靈”的程度遠(yuǎn)小于根植于現(xiàn)實(shí)政治制度中經(jīng)濟(jì)政策不完善所引起的“政治失靈”壟斷競(jìng)爭(zhēng)MonopolisticCompetition壟斷競(jìng)爭(zhēng)的特征：企業(yè)數(shù)量多而規(guī)模相對(duì)較小；產(chǎn)品相似但又彼此有差別；企業(yè)在市場(chǎng)上的進(jìn)入和退出不受限制。星巴克（Starbucks）

的興衰星巴克：不再差異化？Starbucks:Nolongerdifferentenough?開始的繁榮1971年開出第一家店（西雅圖）1993年在東海岸開店上十年繁榮，全球38個(gè)國(guó)家經(jīng)營(yíng)，共有17000家店激烈的競(jìng)爭(zhēng)和不景氣的經(jīng)濟(jì)2008年在美國(guó)關(guān)閉600家2009年在美國(guó)關(guān)閉300多家降價(jià)克服“$4咖啡之家”印象在壟斷競(jìng)爭(zhēng)的市場(chǎng)，長(zhǎng)期維持利潤(rùn)非常困難！2011年恢復(fù)盈利壟斷競(jìng)爭(zhēng)與完全競(jìng)爭(zhēng)、壟斷的比較壟斷競(jìng)爭(zhēng)與完全競(jìng)爭(zhēng)的差別：在壟斷競(jìng)爭(zhēng)條件下，企業(yè)生產(chǎn)有差異的產(chǎn)品；壟斷競(jìng)爭(zhēng)與壟斷的差別：在壟斷競(jìng)爭(zhēng)條件下，企業(yè)可以自由進(jìn)出市場(chǎng)。假設(shè)：?jiǎn)蝹€(gè)企業(yè)的產(chǎn)出相對(duì)于整個(gè)市場(chǎng)的銷售來(lái)說數(shù)量很小，所以單個(gè)企業(yè)的價(jià)格與產(chǎn)出決策不會(huì)為市場(chǎng)中其他企業(yè)所察覺，企業(yè)之間獨(dú)立運(yùn)作壟斷競(jìng)爭(zhēng)下的短期利潤(rùn)最大化(圖12.7)壟斷競(jìng)爭(zhēng)下的長(zhǎng)期均衡(圖12.8)新企業(yè)進(jìn)入侵蝕利潤(rùn)壟斷競(jìng)爭(zhēng)短期均衡等同于壟斷沒有進(jìn)入退出限制導(dǎo)致了長(zhǎng)期均衡當(dāng)每個(gè)廠商的需求曲線與長(zhǎng)期平均成本曲線LAC相切時(shí)在均衡產(chǎn)出水平下，P=LAC

且

MR=LMC長(zhǎng)期均衡更像一種趨勢(shì)Starbucks面臨McDonald's競(jìng)爭(zhēng)Theeffectofentryonprice,quantity,andprofitsatStarbucks.WhatHappenstoProfitsintheLongRun?壟斷競(jìng)爭(zhēng)廠商的處境類似于查爾斯·狄更斯在《圣誕頌》（ChristmasCarol）中描述的EbenezerScrooge遇到死神的情景。當(dāng)看到自己死亡景象時(shí)，他問死神：那件事（死亡）的預(yù)兆是將來(lái)必然發(fā)生的，還是僅僅可能會(huì)發(fā)生的？利潤(rùn)終結(jié)的預(yù)兆縈繞在每個(gè)廠商所有者心中并揮之不去。TheShortRunandtheLongRunforaMonopolisticallyCompetitiveFirmRelationshipbetweenPrice

andAverageTotalCostProfitandLossElasticityofDemandCurveRelationshipbetweenPrice

andMarginalCostShortRunP>MCLongRunP>MCShortRunP>MCShortRunEconomicprofitShortRunLesselasticdemandcurveorP<ATCorEconomiclossLongRunP=MCLongRunZeroeconomicprofitLongRunMoreelasticdemandcurveAbercrombie&Fitch:CantheProductBeTooDifferentiated?DidAbercrombieandFitchnarrowitstargetmarkettoomuch?Afirmwhosestrategyofproductdifferentiationsucceedswillexperienceincreasesinsame-storesales.CanItBeProfitabletoBetheHigh-PriceSeller?Becausethegreaterdemandmorethanoffsetsthehighercosts,thehhgreggstoremakesalargerprofit.MidnightSnackFigure1:Productdifferentiationshiftingthedemand

curveforamonopolisticcompetitorFigure2:“Spreadingtheoverhead”壟斷競(jìng)爭(zhēng)與完全競(jìng)爭(zhēng)的長(zhǎng)期均衡比較Inpanel(b),amonopolisticallycompetitivefirmproducesatQMC,wherepriceisgreaterthanmarginalcost,andaveragetotalcostisnotataminimum.Asaresult,themonopolisticallycompetitivefirmisneitherallocativelyefficientnorproductivelyefficient.Themonopolisticallycompetitivefirmhasexcesscapacityequaltothedifferencebetweenitsprofit-maximizinglevelofoutputandtheproductivelyefficientlevelofoutput.壟斷競(jìng)爭(zhēng)與完全競(jìng)爭(zhēng)的長(zhǎng)期均衡比較定價(jià)高于其邊際成本，沒有配置效率；不在平均成本最低點(diǎn)上生產(chǎn)，沒有生產(chǎn)效率；增加產(chǎn)量可以降低其平均成本。IsMonopolisticCompetitionInefficient?HowConsumersBenefitfromMonopolisticCompetitionConsumersbenefitfrombeingabletopurchaseaproductthatisdifferentiatedandmorecloselysuitedtotheirtastes.MarketingAlltheactivitiesnecessaryforafirmtosellaproducttoaconsumer.BrandmanagementTheactionsofafirmintendedtomaintainthedifferentiationofaproductovertime.AdvertisingIftheincreaseinrevenuethatresultsfromadvertisingisgreaterthantheincreaseincosts,thefirm’sprofitswillrise.DefendingaBrandNameAfirmcanapplyforatrademark,whichgrantslegalprotectionagainstotherfirmsusingitsproduct’sname.Legallyenforcingtrademarkscanbedifficult.U.S.firmsoftenfinditdifficulttoenforcetheirtrademarksinthecourtsofsomeforeigncountries,Product

Differentiation差異化戰(zhàn)略：品牌與廣告銷售差異化產(chǎn)品的企業(yè)：通?；ㄙM(fèi)其總收益的10-20%用于廣告。總體上講，企業(yè)大約用其收益的2%作廣告。廣告AdvertisementWhenfirmsselldifferentiatedproductsandchargepricesabovemarginalcost,eachfirmhasanincentivetoadvertiseinordertoattractmorebuyerstoitsparticularproduct.品牌管理BrandManagementBrandManagementTheactionsofafirmintendedtomaintainthedifferentiationofaproductovertime.Inmanymarkets,brandnameproductscoexistwithgenericones.Firmswithbrandnamesusuallyspendmoreonadvertising,chargehigherpricesfortheproducts.Aswithadvertising,thereisdisagreementabouttheeconomicsofbrandnames…

What’sYourOpinions？0TheCritiqueofBrandNamesCriticsofbrandnamesbelieve:Brandnamescauseconsumerstoperceivedifferencesthatdonotreallyexist.Consumers’willingnesstopaymoreforbrandnamesisirrational,fosteredbyadvertising.Eliminatinggovtprotectionoftrademarkswouldreduceinfluenceofbrandnames,

resultinlowerprices.0TheDefenseofBrandNamesDefendersofbrandnamesbelieve:Brandnamesprovideinformationaboutqualitytoconsumers.信息并不在廣告的內(nèi)容中，而僅僅在于廣告的存在與其昂貴的價(jià)格中。Companieswithbrandnameshaveincentivetomaintainquality,toprotectthereputationoftheirbrandnames.0EFFECTSOFADVERTISINGTheDecisionWhethertoAdvertiseD（AR）andMRaredemandandmarginalrevenuewhenthefirmdoesn’tadvertise,andACandMCareaverageandmarginalcost.ThefirmproducesQ0andreceivesapriceP0.Itstotalprofitπ0isgivenbythegray-shadedrectangle.Ifthefirmadvertises,itsdemandandmarginalrevenuecurvesshifttotheright.Averagecostrises(toAC′)butmarginalcostremainsthesame.ThefirmnowproducesQ1(whereMR′=MC),andreceivesapriceP1.Itstotalprofit,π1,isnowlarger.HowMuchtoAdvertiseGiventhemaximizationproblem:Theprofit-maximizingo