精編14 競(jìng)爭(zhēng)性市場(chǎng)課件

?2007ThomsonSouth-Western銻圃枝據(jù)訝磕室潑九課芬按枕伶升掩抖氰傷彰廢撬旗型植簽衙簾事勸熔醉14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)?2007ThomsonSouth-Western銻圃WHATISACOMPETITIVEMARKET?

什么是競(jìng)爭(zhēng)性市場(chǎng)?Acompetitivemarkethasmanybuyersandsellerstradingidenticalproductssothateachbuyerandsellerisapricetaker.競(jìng)爭(zhēng)性市場(chǎng)擁有許多買者和賣者,他們所交易的是相同的產(chǎn)品,因此每一個(gè)買者和賣者都是價(jià)格的接受者.Buyersandsellersmustacceptthepricedeterminedbythemarket.買者和賣者必須接受市場(chǎng)決定的價(jià)格.供板嘗覺(jué)腿寒蘑攏勞禮持塞老疤錄嶄魯贍滌襟檢鈾枯某混緣脊拎盲甲遵了14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)WHATISACOMPETITIVEMARKET?

TheMeaningofCompetition

競(jìng)爭(zhēng)的涵義Aperfectly

competitivemarket

hasthefollowingcharacteristics:一個(gè)完全競(jìng)爭(zhēng)的市場(chǎng)具有下列特征:Therearemanybuyersandsellersinthemarket.市場(chǎng)上存在著許多買者和賣者Thegoodsofferedbythevarioussellersarelargelythesame.由各個(gè)不同的賣者所提供的商品在很大程度上是相同的。Firmscanfreelyenterorexitthemarket.企業(yè)能夠自由地進(jìn)入和退出市場(chǎng)。茫司驚域翟嘔睡臍鉆哆句詹吸熒硅憂舊幟執(zhí)殉豫抽坍拙亂券烷抽誠(chéng)排戈贍14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheMeaningofCompetition

競(jìng)爭(zhēng)的TheMeaningofCompetition

競(jìng)爭(zhēng)的涵義Asaresultofitscharacteristics,theperfectlycompetitivemarkethasthefollowingoutcomes:作為其特征的結(jié)果，完全競(jìng)爭(zhēng)市場(chǎng)具有下列結(jié)果：Theactionsofanysinglebuyerorsellerinthemarkethaveanegligibleimpactonthemarketprice.市場(chǎng)上任何單一的買者或賣者對(duì)市場(chǎng)價(jià)格的影響都是微不足道的。Eachbuyerandsellertakesthemarketpriceasgiven.

每一個(gè)買者或賣者把市場(chǎng)價(jià)格都看作是給定的。虱苑煩驗(yàn)作涂莎論子攝跺壽敬凰適篆楞簇圭痘填墮辯爹擯壘跌給陸?yīng)z閱湊14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheMeaningofCompetition

競(jìng)爭(zhēng)的TheRevenueofaCompetitiveFirm

競(jìng)爭(zhēng)性企業(yè)的收益Totalrevenueforafirmisthesellingpricetimesthequantitysold.企業(yè)的總收益是銷售價(jià)格乘出售的數(shù)量TR=(P

Q)Totalrevenueisproportionaltotheamountofoutput.總收益與產(chǎn)出數(shù)量成比例字憎斌慷纜襖契期部梨繃滋貌爹冶究藤仙訓(xùn)轅挪閨蒸菊突載幟泡僑琉問(wèn)徑14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheRevenueofaCompetitiveFTheRevenueofaCompetitiveFirm

競(jìng)爭(zhēng)性企業(yè)的收益Averagerevenuetellsushowmuchrevenueafirmreceivesforthetypicalunitsold.平均收益告訴我們一個(gè)企業(yè)從銷售的典型單位中獲取多少收益Averagerevenueistotalrevenuedividedbythequantitysold.平均收益是總收益除銷售數(shù)量總?cè)瓌?wù)籃佛創(chuàng)瀑閻墳婚糾伯焉惜廓玄瞎浩臨磨奪豐吶翌安歸值患育祭猜14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheRevenueofaCompetitiveFTheRevenueofaCompetitiveFirm

競(jìng)爭(zhēng)性企業(yè)的收益Inperfectcompetition,averagerevenueequalsthepriceofthegood.在完全競(jìng)爭(zhēng)中，平均收益等于商品的價(jià)格。藥礙蘭繳地卜柔的仁汽鋇謠弊鑄乃疾組歇逝種秘陛啼融敵抉濰嫁裹籌鉸葬14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheRevenueofaCompetitiveFTheRevenueofaCompetitiveFirm

競(jìng)爭(zhēng)性企業(yè)的收益Marginalrevenueisthechangeintotalrevenuefromanadditionalunitsold.邊際收益是來(lái)自新增一單位銷售的總收益變化MR=TR/QForcompetitivefirms,marginalrevenueequalsthepriceofthegood.對(duì)于競(jìng)爭(zhēng)性企業(yè)來(lái)說(shuō)，邊際收益等于商品的價(jià)格?；蠛敫G譚漫濾兜驕至瑤呈莉陌逾劃鞏拭絹罵酮犀筷沈謾砷隱鎳丘屢匯盯湛14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheRevenueofaCompetitiveFTable1Total,Average,andMarginalRevenueforaCompetitiveFirm

策壽檔戀一妊燃洪垂舀芭苗蠟幫布檢淄巴偷疾募談宏級(jí)綢嶼住者而伏崗底14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Table1Total,Average,andMPROFITMAXIMIZATIONANDTHECOMPETITIVEFIRM’SSUPPLYCURVE

利潤(rùn)最大化與競(jìng)爭(zhēng)性企業(yè)的供給曲線Thegoalofacompetitivefirmistomaximizeprofit.競(jìng)爭(zhēng)性企業(yè)的目標(biāo)是使利潤(rùn)達(dá)到最大化Thismeansthatthefirmwillwanttoproducethequantitythatmaximizesthedifferencebetweentotalrevenueandtotalcost.這意味著企業(yè)想要生產(chǎn)的數(shù)量能夠使得總收益與總成本之間的差額達(dá)到最大化。慰響倚耶儒更草篙蓑慘環(huán)孺渦鯨牛臻乏熬赤淡鑿儈哇享遁苯秩毖踏甭店蓉14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)PROFITMAXIMIZATIONANDTHECOTable2ProfitMaximization:ANumericalExample

表2：利潤(rùn)最大化---一個(gè)數(shù)字化范例豬默魂斌粥其矢密殃痛啃瑤屏柬崩拄董簧撼站癬醫(yī)鏈昨獵凳御誹紫批玫眼14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Table2ProfitMaximization:TheMarginalCost-CurveandtheFirm’sSupplyDecision

邊際成本曲線與企業(yè)的供給決策Profitmaximizationoccursatthequantitywheremarginalrevenueequalsmarginalcost.利潤(rùn)最大化出現(xiàn)在邊際收益等于邊際成本的數(shù)量上。WhenMR>MC,increaseQ當(dāng)邊際收益大于邊際成本時(shí)，數(shù)量增加。WhenMR<MC,decreaseQ當(dāng)邊際收益小于邊際成本時(shí)，數(shù)量減少。WhenMR=MC,profitismaximized.當(dāng)邊際收益等于邊際成本時(shí)，利潤(rùn)達(dá)到最大化。仗簍袖檻巨旋查找義遍燈浩葛遂楔重獸綽敝步棋溝淤瘩程赫淪嫌伐獄幣椿14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheMarginalCost-CurveandthFigure1ProfitMaximizationforaCompetitiveFirm

圖1：競(jìng)爭(zhēng)性企業(yè)的利潤(rùn)最大化Quantity0CostsandRevenueMCATCAVCMC1Q1MC2Q2Thefirmmaximizesprofitbyproducingthequantityatwhichmarginalcostequalsmarginalrevenue.QMAXP=MR1=MR2P=AR=MRIfthefirmproducesQ1,marginalcostisMC1.IfthefirmproducesQ2,marginalcostisMC2.SupposethemarketpriceisP.仙曉撒啤跳日翌隘淘怎敗需靶圈呻篆措敖央飯嘗扦形審綁韶毅鉗齲撰幌絕14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure1ProfitMaximizationfFigure2MarginalCostastheCompetitiveFirm’sSupplyCurve

圖2：作為競(jìng)爭(zhēng)性企業(yè)供給曲線的邊際成本Quantity0PriceMCATCAVCP1Q1P2Q2So,thissectionofthefirm’sMCcurveisalsothefirm’ssupplycurve.AsPincreases,thefirmwillselectitslevelofoutputalongtheMCcurve.碩腳守沒(méi)舒溉頂餒皖塘釁鄲誘餌栓氦鰓培恒廢鑄渝棵刊藕勾需祿澈莫裂秦14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure2MarginalCostastheTheFirm’sShort-RunDecisiontoShutDown

企業(yè)關(guān)閉的短期決策Ashutdownreferstoashort-rundecisionnottoproduceanythingduringaspecificperiodoftimebecauseofcurrentmarketconditions.暫時(shí)關(guān)閉是指在某一特定時(shí)期內(nèi)因?yàn)楫?dāng)時(shí)的市場(chǎng)條件而決定不生產(chǎn)任何東西的短期決策Exitreferstoalong-rundecisiontoleavethemarket.退出是指離開(kāi)市場(chǎng)的長(zhǎng)期決策鹵寫娘餞傻匡鈉恃貳寥姚格酶掐琺彩拷捍瓢攝粘瀑寇吳叁隕嘲頹助坦嚎顏14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheFirm’sShort-RunDecisionTheFirm’sShort-RunDecisiontoShutDown

企業(yè)關(guān)閉的短期決策Thefirmshutsdowniftherevenueitgetsfromproducingislessthanthevariablecostofproduction.如果來(lái)自其生產(chǎn)的收益小于生產(chǎn)成本時(shí)，企業(yè)會(huì)暫時(shí)關(guān)閉。ShutdownifTR<VCShutdownifTR/Q<VC/QShutdownifP<AVC吼晃筏束焦逗訖盼征地顴隋慎搖怨浙澗仇先凳葛側(cè)毛仲拾郊更看墩夜忿唉14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheFirm’sShort-RunDecisionFigure3TheCompetitiveFirm’sShort-RunSupplyCurve

圖3：競(jìng)爭(zhēng)性企業(yè)的短期供給曲線MCQuantityATCAVC0CostsFirmshutsdownifP<AVCFirm’sshort-runsupplycurveIfP>AVC,firmwillcontinuetoproduceintheshortrun.IfP>ATC,thefirmwillcontinuetoproduceataprofit.剿障逾艘毋跨阿剮指借攢穆唆碩啟赫瑤餞吠帖妙南禽樊劑圾幾碘罩玄八煮14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure3TheCompetitiveFirm’SpiltMilkandOtherSunkCostsThefirmconsidersitssunkcostswhendecidingtoexit,butignoresthemwhendecidingwhethertoshutdown.在決定退出時(shí)企業(yè)考慮其沉淀成本，但是在決定是否暫時(shí)關(guān)閉時(shí)可忽略沉淀成本。Sunkcostsarecoststhathavealreadybeencommittedandcannotberecovered.沉淀成本是已經(jīng)投入并且無(wú)法挽回的成本兒鏈堤癥句羅蜜埋皿砍鈍徑豈黑履鱗勁潦剛騙濱裁拴鑰埋聞?wù)軕\杉噶掐14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)SpiltMilkandOtherSunkCostTheFirm’sShort-RunDecisiontoShutDown

企業(yè)關(guān)閉的短期決策Theportionofthemarginal-costcurvethatliesaboveaveragevariablecostisthecompetitivefirm’sshort-runsupplycurve.邊際成本曲線位于平均可變成本以上的部分是競(jìng)爭(zhēng)性企業(yè)的短期供給曲線。罵寓舜較排嘩礎(chǔ)韋擻源強(qiáng)鶴演弛抒眨臆辮灘蘆辦虧枝迄虛紀(jì)噴畫評(píng)釘?shù)鋼P(yáng)14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheFirm’sShort-RunDecisionTheFirm’sLong-RunDecisiontoExitorEnteraMarket

企業(yè)退出或者進(jìn)入一個(gè)市場(chǎng)的長(zhǎng)期決策Inthelongrun,thefirmexitsiftherevenueitwouldgetfromproducingislessthanitstotalcost.在長(zhǎng)期中，如果企業(yè)從生產(chǎn)中獲得的收益小于其總成本的話，它就退出。ExitifTR<TCExitifTR/Q<TC/QExitifP<ATC涼瓜幀夾疇逢綻入箔畜勞毛謹(jǐn)放叭準(zhǔn)終勉穴詛螞挎菩販棠坐扎利維丹續(xù)眠14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheFirm’sLong-RunDecisiontTheFirm’sLong-RunDecisiontoExitorEnteraMarket

企業(yè)退出或者進(jìn)入一個(gè)市場(chǎng)的長(zhǎng)期決策Afirmwillentertheindustryifsuchanactionwouldbeprofitable.如果此類行為有利可圖的話，企業(yè)將進(jìn)入該行業(yè)。EnterifTR>TCEnterifTR/Q>TC/QEnterifP>ATC畜忻陰鑄擔(dān)鄰蟲硼鐵瘦痢潰敵浙怔忠煎這祟款俐洋捻嬰墻簡(jiǎn)吼胳碼孤止渤14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheFirm’sLong-RunDecisiontFigure4TheCompetitiveFirm’sLong-RunSupplyCurve

圖4：競(jìng)爭(zhēng)性市場(chǎng)的長(zhǎng)期供給曲線MC=long-runSFirmexitsifP<ATCQuantityATC0CostsFirm’slong-runsupplycurveFirmentersifP>ATC饞宦旭遏騎顧兌每弱帝瑟禾默輥牽爺蟄掩撓瑰度簧乳聲禍挺瞪棄曙燕雀輝14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure4TheCompetitiveFirm’MeasuringProfitinOurGraphfortheCompetitiveFirm

在我們有關(guān)競(jìng)爭(zhēng)性企業(yè)的圖中測(cè)度利潤(rùn)Profit=TR–TCProfit=(TR/Q–TC/Q)xQProfit=(P–ATC)xQ氰溉造條立燴照森作咸挎響猩郴殃駝膩異橋虐騾薯插躬掏掇巖嗎著認(rèn)躺廁14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)MeasuringProfitinOurGraphFigure5ProfitastheAreabetweenPriceandAverageTotalCost

圖5：價(jià)格與平均總成本之間的面積是利潤(rùn)AFirmwithProfits有利潤(rùn)的企業(yè)Quantity0PriceP=AR=MRATCMCPATCQ(profit-maximizingquantity)利潤(rùn)最大化數(shù)量Profit討堪耶侖剩盅蔑麥佩嘻會(huì)撬敏瘁頗涯遁掏肛永閡蹬壓蔡顛譬娩餞佐她遍被14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure5ProfitastheAreabeFigure5LossastheAreabetweenAverageTotalCostandPrice

圖5：平均總成本與價(jià)格之間的面積是虧損(b)AFirmwithLosses

有虧損的企業(yè)Quantity0PriceATCMC(loss-minimizingquantity)虧損最小數(shù)量P=AR=MRPATCQLoss墳筋袋戍沂碎撇鵲演契需運(yùn)穢沒(méi)賊幌民父遠(yuǎn)蔣佰工白廟酵鍍腑氯縮攀媚丙14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure5LossastheAreabetwTHESUPPLYCURVEINACOMPETITIVEMARKET

競(jìng)爭(zhēng)性市場(chǎng)中的供給曲線Thecompetitivefirm’slong-runsupplycurveistheportionofitsmarginal-costcurvethatliesaboveaveragetotalcost.競(jìng)爭(zhēng)性企業(yè)的長(zhǎng)期供給曲線是位于平均總成本曲線之上的邊際成本曲線。拽難唆楔似麓項(xiàng)焰眉揉混靶瞅軸嗽傣寸掠含骨摧垮致訛轉(zhuǎn)防邵罕并令袁楷14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)THESUPPLYCURVEINACOMPETITTHESUPPLYCURVEINACOMPETITIVEMARKET

競(jìng)爭(zhēng)性市場(chǎng)中的供給曲線Short-RunSupplyCurve短期供給曲線Theportionofitsmarginalcostcurvethatliesaboveaveragevariablecost.

邊際成本曲線位于平均可變成本之上的部分Long-RunSupplyCurve長(zhǎng)期供給曲線Themarginalcostcurveabovetheminimumpointofitsaveragetotalcostcurve.邊際成本曲線位于其平均總成本曲線的最低點(diǎn)之上頰償揪寐貝戚瀾佩態(tài)素捐盒沒(méi)梅飼摸汗榔韓鑼蕊簧糙午落措漓嫌蛔譬蟹溯14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)THESUPPLYCURVEINACOMPETITTHESUPPLYCURVEINACOMPETITIVEMARKET

競(jìng)爭(zhēng)性市場(chǎng)中的供給曲線Marketsupplyequalsthesumofthequantitiessuppliedbytheindividualfirmsinthemarket.市場(chǎng)供給等于市場(chǎng)中個(gè)別企業(yè)所供給的數(shù)量之總和蕩燴致回磺硬尿齡糞丈王宦快脾條受腔禹繭妖噸挫購(gòu)宇螞詭臨垢憎槐匣優(yōu)14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)THESUPPLYCURVEINACOMPETITTheShortRun:MarketSupplywithaFixedNumberofFirms

短期：企業(yè)數(shù)量固定的市場(chǎng)供給Foranygivenprice,eachfirmsuppliesaquantityofoutputsothatitsmarginalcostequalsprice.對(duì)于任何給定的價(jià)格，每一企業(yè)供給特定的產(chǎn)出數(shù)量。以便使其邊際成本等于價(jià)格。Themarketsupplycurvereflectstheindividualfirms’marginalcostcurves.市場(chǎng)供給曲線反映出個(gè)別企業(yè)的邊際成本曲線凸確眾狼邀喊賢船棗捧曙俘陛幽眠膚算猖獸因匡資澗率斜亥威亡槽房踏園14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheShortRun:MarketSupplywFigure6Short-RunMarketSupply

圖6：短期市場(chǎng)供給IndividualFirmSupply個(gè)別企業(yè)的供給Quantity(firm)0PriceMC1.00100$2.00200(b)MarketSupply市場(chǎng)供給Quantity(market)0PriceSupply1.00100,000$2.00200,000Iftheindustryhas1000identicalfirms,thenateachmarketprice,industryoutputwillbe1000timeslargerthantherepresentativefirm’soutput.如果該產(chǎn)業(yè)擁有一千家相同企業(yè)，該產(chǎn)業(yè)的產(chǎn)出將比代表性企業(yè)的產(chǎn)出大一千倍。蚊貓闊賂余念彥升匪憑刊奪樁榨亂德灶聽(tīng)悄扁撻鼎閩怖狀倒淪烏鴿垂菲廈14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure6Short-RunMarketSupTheLongRun:MarketSupplywithEntryandExit

長(zhǎng)期：有進(jìn)入與退出的市場(chǎng)供給Firmswillenterorexitthemarketuntilprofitisdriventozero.企業(yè)將進(jìn)入或退出市場(chǎng)直到利潤(rùn)趨向于零Inthelongrun,priceequalstheminimumofaveragetotalcost.在長(zhǎng)期中，價(jià)格等于平均總成本的最低點(diǎn)。Thelong-runmarketsupplycurveishorizontalatthisprice.長(zhǎng)期市場(chǎng)供給曲線在此價(jià)格呈水平狀暖裕稗快莉悄藹閥弛卜眶詠勃塢昏木閨睦駐伎欣奄芭全牽噸皆宗嘿主于呸14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheLongRun:MarketSupplywiFigure7Long-RunMarketSupply

圖7：長(zhǎng)期市場(chǎng)供給(a)Firm’sZero-ProfitConditionQuantity(firm)0Price(b)MarketSupplyQuantity(market)Price0P=minimumATCSupplyMCATC交檔乞腸葷昆被賄眠犯曲縱畜才才戀脅哄古佩脂賀跌叁技戀闌才煌棱嗅遵14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure7Long-RunMarketSuppTheLongRun:MarketSupplywithEntryandExit

長(zhǎng)期：有進(jìn)入與退出的市場(chǎng)供給Attheendoftheprocessofentryandexit,firmsthatremainmustbemakingzeroeconomicprofit.在進(jìn)入和退出過(guò)程結(jié)束時(shí)，留存的企業(yè)必定獲得零經(jīng)濟(jì)利潤(rùn)。Theprocessofentryandexitendsonlywhenpriceandaveragetotalcostaredriventoequality.只有在價(jià)格與平均總成本趨向相等時(shí)，進(jìn)入和退出過(guò)程才會(huì)結(jié)束。Long-runequilibriummusthavefirmsoperatingattheirefficientscale.長(zhǎng)期均衡必定使得企業(yè)在其有效規(guī)模水平上運(yùn)行即柜爸廓此煌似朋駭抽值弦大靈纂蘸得擊隨宙銥雛漬挑砸厘卻炸冷彤遞椿14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheLongRun:MarketSupplywiWhyDoCompetitiveFirmsStayinBusinessIfTheyMakeZeroProfit?

為什么競(jìng)爭(zhēng)性企業(yè)在獲得零利潤(rùn)時(shí)還要留存在其業(yè)務(wù)之中？Profitequalstotalrevenueminustotalcost.利潤(rùn)等于總收益減去總成本Totalcostincludesalltheopportunitycostsofthefirm.總成本包括企業(yè)的所有機(jī)會(huì)成本Inthezero-profitequilibrium,thefirm’srevenuecompensatestheownersforthetimeandmoneytheyexpendtokeepthebusinessgoing.在零利潤(rùn)均衡中，企業(yè)的收益補(bǔ)償了所有者為了維持業(yè)務(wù)運(yùn)行所花費(fèi)的時(shí)間和金錢。模驕篡芬戳?xí)哼_(dá)乓對(duì)姨來(lái)束臉獰鉆榷疙聾號(hào)渭緊雀冀種兜自陷揖廄喻吹嘔14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)WhyDoCompetitiveFirmsStayAShiftinDemandintheShortRunandLongRun

短期與長(zhǎng)期中的需求變動(dòng)Anincreaseindemandraisespriceandquantityintheshortrun.在短期內(nèi)，需求增加會(huì)提高價(jià)格和數(shù)量。Firmsearnprofitsbecausepricenowexceedsaveragetotalcost.企業(yè)獲得利潤(rùn)，因?yàn)槟壳皟r(jià)格超越了總成本。襪瀾雷洪現(xiàn)狄僑痊郭噓眩林脂瑞鳥番玖能愚頓沾卸睦往翔稅犁鈴柜交稚瑚14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)AShiftinDemandintheShortFigure8AnIncreaseinDemandintheShortRunandLongRun

圖8：短期與長(zhǎng)期中的需求增加FirmInitialCondition初始條件Quantity(firm)0PriceMarketQuantity(market)Price0DDemand,1SShort-runsupply,1P1ATCLong-runsupplyP11QAMCAmarketbeginsinlongrunequilibrium.在長(zhǎng)期均衡中市場(chǎng)啟動(dòng)Andfirmsearnzeroprofit.企業(yè)獲得零利潤(rùn)俊斗軋棺銑演復(fù)臂苦辯發(fā)騰躁浚儉尚陣蜒段膘末看噪膜繡蛹?jí)ㄍ幕战o乎14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure8AnIncreaseinDemandFigure8AnIncreaseinDemandintheShortRunandLongRun

圖8：短期和長(zhǎng)期中的需求增加MarketFirm(b)Short-RunResponse短期反應(yīng)Quantity(firm)0PriceP1Quantity(market)Long-runsupplyPrice0D1D2P1S1P2Q1AQ2P2BATCMCAnincreaseinmarketdemand……raisespriceandoutput.ThehigherPencouragesfirmstoproducemore……andgeneratesshort-runprofit.評(píng)死居邁篩供上太渙缸卓等堤崗吊芳形勺潮撕箕森晦戊葉液扳緣富孵揀午14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure8AnIncreaseinDemandFigure8AnIncreaseinDemandintheShortRunandLongRun

圖8：短期與長(zhǎng)期中的需求增加P1Firm(c)Long-RunResponse長(zhǎng)期反應(yīng)Quantity(firm)0PriceMCATCMarketQuantity(market)Price0P1P2Q1Q2Long-runsupplyBD1D2S1AS2Q3CProfitsinduceentryandmarketsupplyincreases.利潤(rùn)引致進(jìn)入和市場(chǎng)供給增加Theincreaseinsupplylowersmarketprice.供給增加減低市場(chǎng)價(jià)格Inthelongrunmarketpriceisrestored,butmarketsupplyisgreater.鏟寒椰藹戍箭烴低倘西擯滑粕卷株稚劊猜口斟哥顴盔拇朵孵籌坍十僑緯掉14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure8AnIncreaseinDemandWhytheLong-RunSupplyCurveMightSlopeUpward

為什么長(zhǎng)期供給曲線會(huì)向上傾斜？Someresourcesusedinproductionmaybeavailableonlyinlimitedquantities.生產(chǎn)中使用的某些資源也許只能以有限的數(shù)量獲得Firmsmayhavedifferentcosts.企業(yè)也許具有不同的成本MarginalFirm邊際企業(yè)Themarginalfirmisthefirmthatwouldexitthemarketifthepricewereanylower.邊際企業(yè)是在價(jià)格降低時(shí)會(huì)退出市場(chǎng)的企業(yè)最霧蚤倡攏思嫉蛙園使釬酒輻談幣祝蠕逞封荒掃力登咽歷呢朋圾穆繩詫躇14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)WhytheLong-RunSupplyCurveBecauseacompetitivefirmisapricetaker,itsrevenueisproportionaltotheamountofoutputitproduces.因?yàn)楦?jìng)爭(zhēng)性企業(yè)是價(jià)格接受者，它的收益是與其生產(chǎn)的數(shù)量成比例的。Thepriceofthegoodequalsboththefirm’saveragerevenueanditsmarginalrevenue.商品的價(jià)格等于企業(yè)的平均收益和它的邊際收益試丘胞莢俯必醫(yī)拾蠻嶼獎(jiǎng)耕緝?nèi)笣ⅹz朵盼饋粘團(tuán)箕木八脈利磕懲節(jié)嚙睛黨14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)BecauseacompetitivefirmisTomaximizeprofit,afirmchoosesthequantityofoutputsuchthatmarginalrevenueequalsmarginalcost.為了達(dá)到利潤(rùn)最大化，企業(yè)選擇使得邊際收益等于邊際成本的產(chǎn)出數(shù)量。Thisisalsothequantityatwhichpriceequalsmarginalcost.這也是價(jià)格等于邊際成本時(shí)的數(shù)量Therefore,thefirm’smarginalcostcurveisitssupplycurve.因此，企業(yè)的邊際成本曲線就是其供給曲線。甫憐尾吞搬鏟喲痢朝銜灑頃搔奠茫堰躬咸羽嘶耳帚籍乾堆諧晦腔棉陪柄坐14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Tomaximizeprofit,afirmchoIntheshortrun,whenafirmcannotrecoveritsfixedcosts,thefirmwillchoosetoshutdowntemporarilyifthepriceofthegoodislessthanaveragevariablecost.在短期中，當(dāng)某一企業(yè)不能覆蓋其固定成本時(shí)，如果商品的價(jià)格低于平均可變成本時(shí)，企業(yè)將選擇暫時(shí)關(guān)閉。Inthelongrun,whenthefirmcanrecoverbothfixedandvariablecosts,itwillchoosetoexitifthepriceislessthanaveragetotalcost.在長(zhǎng)期中，當(dāng)企業(yè)能夠覆蓋固定成本和可變成本時(shí)，如果價(jià)格低于平均總成本時(shí)，它將選擇退出。亞剃傈蹈孟殲燭攣壟甥篙孔男狀見(jiàn)溝蛀陰領(lǐng)壇恐剃謹(jǐn)價(jià)伐梗跡銑礙忽遵昭14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Intheshortrun,whenafirmInamarketwithfreeentryandexit,profitsaredriventozerointhelongrunandallfirmsproduceattheefficientscale.在自由進(jìn)入與退出的市場(chǎng)中，利潤(rùn)在長(zhǎng)期中趨向于零，并且所有企業(yè)都在有效規(guī)模水平上生產(chǎn)。Changesindemandhavedifferenteffectsoverdifferenttimehorizons.需求的變化在不同的時(shí)間區(qū)間具有不同的效應(yīng)。Inthelongrun,thenumberoffirmsadjuststodrivethemarketbacktothezero-profitequilibrium.在長(zhǎng)期中，企業(yè)的數(shù)量調(diào)整到把市場(chǎng)驅(qū)趕到零利潤(rùn)均衡。邯刷子策忌棲召關(guān)訪焙痰峪糞詠烹肺紗哦附熔自挑廬呵余謄疫希擱芽綏囪14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Inamarketwithfreeentryan?2007ThomsonSouth-Western銻圃枝據(jù)訝磕室潑九課芬按枕伶升掩抖氰傷彰廢撬旗型植簽衙簾事勸熔醉14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)?2007ThomsonSouth-Western銻圃WHATISACOMPETITIVEMARKET?

什么是競(jìng)爭(zhēng)性市場(chǎng)?Acompetitivemarkethasmanybuyersandsellerstradingidenticalproductssothateachbuyerandsellerisapricetaker.競(jìng)爭(zhēng)性市場(chǎng)擁有許多買者和賣者,他們所交易的是相同的產(chǎn)品,因此每一個(gè)買者和賣者都是價(jià)格的接受者.Buyersandsellersmustacceptthepricedeterminedbythemarket.買者和賣者必須接受市場(chǎng)決定的價(jià)格.供板嘗覺(jué)腿寒蘑攏勞禮持塞老疤錄嶄魯贍滌襟檢鈾枯某混緣脊拎盲甲遵了14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)WHATISACOMPETITIVEMARKET?

TheMeaningofCompetition

競(jìng)爭(zhēng)的涵義Aperfectly

competitivemarket

hasthefollowingcharacteristics:一個(gè)完全競(jìng)爭(zhēng)的市場(chǎng)具有下列特征:Therearemanybuyersandsellersinthemarket.市場(chǎng)上存在著許多買者和賣者Thegoodsofferedbythevarioussellersarelargelythesame.由各個(gè)不同的賣者所提供的商品在很大程度上是相同的。Firmscanfreelyenterorexitthemarket.企業(yè)能夠自由地進(jìn)入和退出市場(chǎng)。茫司驚域翟嘔睡臍鉆哆句詹吸熒硅憂舊幟執(zhí)殉豫抽坍拙亂券烷抽誠(chéng)排戈贍14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheMeaningofCompetition

競(jìng)爭(zhēng)的TheMeaningofCompetition

競(jìng)爭(zhēng)的涵義Asaresultofitscharacteristics,theperfectlycompetitivemarkethasthefollowingoutcomes:作為其特征的結(jié)果，完全競(jìng)爭(zhēng)市場(chǎng)具有下列結(jié)果：Theactionsofanysinglebuyerorsellerinthemarkethaveanegligibleimpactonthemarketprice.市場(chǎng)上任何單一的買者或賣者對(duì)市場(chǎng)價(jià)格的影響都是微不足道的。Eachbuyerandsellertakesthemarketpriceasgiven.

每一個(gè)買者或賣者把市場(chǎng)價(jià)格都看作是給定的。虱苑煩驗(yàn)作涂莎論子攝跺壽敬凰適篆楞簇圭痘填墮辯爹擯壘跌給陸?yīng)z閱湊14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheMeaningofCompetition

競(jìng)爭(zhēng)的TheRevenueofaCompetitiveFirm

競(jìng)爭(zhēng)性企業(yè)的收益Totalrevenueforafirmisthesellingpricetimesthequantitysold.企業(yè)的總收益是銷售價(jià)格乘出售的數(shù)量TR=(P

Q)Totalrevenueisproportionaltotheamountofoutput.總收益與產(chǎn)出數(shù)量成比例字憎斌慷纜襖契期部梨繃滋貌爹冶究藤仙訓(xùn)轅挪閨蒸菊突載幟泡僑琉問(wèn)徑14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheRevenueofaCompetitiveFTheRevenueofaCompetitiveFirm

競(jìng)爭(zhēng)性企業(yè)的收益Averagerevenuetellsushowmuchrevenueafirmreceivesforthetypicalunitsold.平均收益告訴我們一個(gè)企業(yè)從銷售的典型單位中獲取多少收益Averagerevenueistotalrevenuedividedbythequantitysold.平均收益是總收益除銷售數(shù)量總?cè)瓌?wù)籃佛創(chuàng)瀑閻墳婚糾伯焉惜廓玄瞎浩臨磨奪豐吶翌安歸值患育祭猜14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheRevenueofaCompetitiveFTheRevenueofaCompetitiveFirm

競(jìng)爭(zhēng)性企業(yè)的收益Inperfectcompetition,averagerevenueequalsthepriceofthegood.在完全競(jìng)爭(zhēng)中，平均收益等于商品的價(jià)格。藥礙蘭繳地卜柔的仁汽鋇謠弊鑄乃疾組歇逝種秘陛啼融敵抉濰嫁裹籌鉸葬14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheRevenueofaCompetitiveFTheRevenueofaCompetitiveFirm

競(jìng)爭(zhēng)性企業(yè)的收益Marginalrevenueisthechangeintotalrevenuefromanadditionalunitsold.邊際收益是來(lái)自新增一單位銷售的總收益變化MR=TR/QForcompetitivefirms,marginalrevenueequalsthepriceofthegood.對(duì)于競(jìng)爭(zhēng)性企業(yè)來(lái)說(shuō)，邊際收益等于商品的價(jià)格?；蠛敫G譚漫濾兜驕至瑤呈莉陌逾劃鞏拭絹罵酮犀筷沈謾砷隱鎳丘屢匯盯湛14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheRevenueofaCompetitiveFTable1Total,Average,andMarginalRevenueforaCompetitiveFirm

策壽檔戀一妊燃洪垂舀芭苗蠟幫布檢淄巴偷疾募談宏級(jí)綢嶼住者而伏崗底14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Table1Total,Average,andMPROFITMAXIMIZATIONANDTHECOMPETITIVEFIRM’SSUPPLYCURVE

利潤(rùn)最大化與競(jìng)爭(zhēng)性企業(yè)的供給曲線Thegoalofacompetitivefirmistomaximizeprofit.競(jìng)爭(zhēng)性企業(yè)的目標(biāo)是使利潤(rùn)達(dá)到最大化Thismeansthatthefirmwillwanttoproducethequantitythatmaximizesthedifferencebetweentotalrevenueandtotalcost.這意味著企業(yè)想要生產(chǎn)的數(shù)量能夠使得總收益與總成本之間的差額達(dá)到最大化。慰響倚耶儒更草篙蓑慘環(huán)孺渦鯨牛臻乏熬赤淡鑿儈哇享遁苯秩毖踏甭店蓉14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)PROFITMAXIMIZATIONANDTHECOTable2ProfitMaximization:ANumericalExample

表2：利潤(rùn)最大化---一個(gè)數(shù)字化范例豬默魂斌粥其矢密殃痛啃瑤屏柬崩拄董簧撼站癬醫(yī)鏈昨獵凳御誹紫批玫眼14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Table2ProfitMaximization:TheMarginalCost-CurveandtheFirm’sSupplyDecision

邊際成本曲線與企業(yè)的供給決策Profitmaximizationoccursatthequantitywheremarginalrevenueequalsmarginalcost.利潤(rùn)最大化出現(xiàn)在邊際收益等于邊際成本的數(shù)量上。WhenMR>MC,increaseQ當(dāng)邊際收益大于邊際成本時(shí)，數(shù)量增加。WhenMR<MC,decreaseQ當(dāng)邊際收益小于邊際成本時(shí)，數(shù)量減少。WhenMR=MC,profitismaximized.當(dāng)邊際收益等于邊際成本時(shí)，利潤(rùn)達(dá)到最大化。仗簍袖檻巨旋查找義遍燈浩葛遂楔重獸綽敝步棋溝淤瘩程赫淪嫌伐獄幣椿14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheMarginalCost-CurveandthFigure1ProfitMaximizationforaCompetitiveFirm

圖1：競(jìng)爭(zhēng)性企業(yè)的利潤(rùn)最大化Quantity0CostsandRevenueMCATCAVCMC1Q1MC2Q2Thefirmmaximizesprofitbyproducingthequantityatwhichmarginalcostequalsmarginalrevenue.QMAXP=MR1=MR2P=AR=MRIfthefirmproducesQ1,marginalcostisMC1.IfthefirmproducesQ2,marginalcostisMC2.SupposethemarketpriceisP.仙曉撒啤跳日翌隘淘怎敗需靶圈呻篆措敖央飯嘗扦形審綁韶毅鉗齲撰幌絕14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure1ProfitMaximizationfFigure2MarginalCostastheCompetitiveFirm’sSupplyCurve

圖2：作為競(jìng)爭(zhēng)性企業(yè)供給曲線的邊際成本Quantity0PriceMCATCAVCP1Q1P2Q2So,thissectionofthefirm’sMCcurveisalsothefirm’ssupplycurve.AsPincreases,thefirmwillselectitslevelofoutputalongtheMCcurve.碩腳守沒(méi)舒溉頂餒皖塘釁鄲誘餌栓氦鰓培恒廢鑄渝棵刊藕勾需祿澈莫裂秦14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure2MarginalCostastheTheFirm’sShort-RunDecisiontoShutDown

企業(yè)關(guān)閉的短期決策Ashutdownreferstoashort-rundecisionnottoproduceanythingduringaspecificperiodoftimebecauseofcurrentmarketconditions.暫時(shí)關(guān)閉是指在某一特定時(shí)期內(nèi)因?yàn)楫?dāng)時(shí)的市場(chǎng)條件而決定不生產(chǎn)任何東西的短期決策Exitreferstoalong-rundecisiontoleavethemarket.退出是指離開(kāi)市場(chǎng)的長(zhǎng)期決策鹵寫娘餞傻匡鈉恃貳寥姚格酶掐琺彩拷捍瓢攝粘瀑寇吳叁隕嘲頹助坦嚎顏14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheFirm’sShort-RunDecisionTheFirm’sShort-RunDecisiontoShutDown

企業(yè)關(guān)閉的短期決策Thefirmshutsdowniftherevenueitgetsfromproducingislessthanthevariablecostofproduction.如果來(lái)自其生產(chǎn)的收益小于生產(chǎn)成本時(shí)，企業(yè)會(huì)暫時(shí)關(guān)閉。ShutdownifTR<VCShutdownifTR/Q<VC/QShutdownifP<AVC吼晃筏束焦逗訖盼征地顴隋慎搖怨浙澗仇先凳葛側(cè)毛仲拾郊更看墩夜忿唉14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheFirm’sShort-RunDecisionFigure3TheCompetitiveFirm’sShort-RunSupplyCurve

圖3：競(jìng)爭(zhēng)性企業(yè)的短期供給曲線MCQuantityATCAVC0CostsFirmshutsdownifP<AVCFirm’sshort-runsupplycurveIfP>AVC,firmwillcontinuetoproduceintheshortrun.IfP>ATC,thefirmwillcontinuetoproduceataprofit.剿障逾艘毋跨阿剮指借攢穆唆碩啟赫瑤餞吠帖妙南禽樊劑圾幾碘罩玄八煮14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure3TheCompetitiveFirm’SpiltMilkandOtherSunkCostsThefirmconsidersitssunkcostswhendecidingtoexit,butignoresthemwhendecidingwhethertoshutdown.在決定退出時(shí)企業(yè)考慮其沉淀成本，但是在決定是否暫時(shí)關(guān)閉時(shí)可忽略沉淀成本。Sunkcostsarecoststhathavealreadybeencommittedandcannotberecovered.沉淀成本是已經(jīng)投入并且無(wú)法挽回的成本兒鏈堤癥句羅蜜埋皿砍鈍徑豈黑履鱗勁潦剛騙濱裁拴鑰埋聞?wù)軕\杉噶掐14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)SpiltMilkandOtherSunkCostTheFirm’sShort-RunDecisiontoShutDown

企業(yè)關(guān)閉的短期決策Theportionofthemarginal-costcurvethatliesaboveaveragevariablecostisthecompetitivefirm’sshort-runsupplycurve.邊際成本曲線位于平均可變成本以上的部分是競(jìng)爭(zhēng)性企業(yè)的短期供給曲線。罵寓舜較排嘩礎(chǔ)韋擻源強(qiáng)鶴演弛抒眨臆辮灘蘆辦虧枝迄虛紀(jì)噴畫評(píng)釘?shù)鋼P(yáng)14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheFirm’sShort-RunDecisionTheFirm’sLong-RunDecisiontoExitorEnteraMarket

企業(yè)退出或者進(jìn)入一個(gè)市場(chǎng)的長(zhǎng)期決策Inthelongrun,thefirmexitsiftherevenueitwouldgetfromproducingislessthanitstotalcost.在長(zhǎng)期中，如果企業(yè)從生產(chǎn)中獲得的收益小于其總成本的話，它就退出。ExitifTR<TCExitifTR/Q<TC/QExitifP<ATC涼瓜幀夾疇逢綻入箔畜勞毛謹(jǐn)放叭準(zhǔn)終勉穴詛螞挎菩販棠坐扎利維丹續(xù)眠14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheFirm’sLong-RunDecisiontTheFirm’sLong-RunDecisiontoExitorEnteraMarket

企業(yè)退出或者進(jìn)入一個(gè)市場(chǎng)的長(zhǎng)期決策Afirmwillentertheindustryifsuchanactionwouldbeprofitable.如果此類行為有利可圖的話，企業(yè)將進(jìn)入該行業(yè)。EnterifTR>TCEnterifTR/Q>TC/QEnterifP>ATC畜忻陰鑄擔(dān)鄰蟲硼鐵瘦痢潰敵浙怔忠煎這祟款俐洋捻嬰墻簡(jiǎn)吼胳碼孤止渤14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheFirm’sLong-RunDecisiontFigure4TheCompetitiveFirm’sLong-RunSupplyCurve

圖4：競(jìng)爭(zhēng)性市場(chǎng)的長(zhǎng)期供給曲線MC=long-runSFirmexitsifP<ATCQuantityATC0CostsFirm’slong-runsupplycurveFirmentersifP>ATC饞宦旭遏騎顧兌每弱帝瑟禾默輥牽爺蟄掩撓瑰度簧乳聲禍挺瞪棄曙燕雀輝14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure4TheCompetitiveFirm’MeasuringProfitinOurGraphfortheCompetitiveFirm

在我們有關(guān)競(jìng)爭(zhēng)性企業(yè)的圖中測(cè)度利潤(rùn)Profit=TR–TCProfit=(TR/Q–TC/Q)xQProfit=(P–ATC)xQ氰溉造條立燴照森作咸挎響猩郴殃駝膩異橋虐騾薯插躬掏掇巖嗎著認(rèn)躺廁14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)MeasuringProfitinOurGraphFigure5ProfitastheAreabetweenPriceandAverageTotalCost

圖5：價(jià)格與平均總成本之間的面積是利潤(rùn)AFirmwithProfits有利潤(rùn)的企業(yè)Quantity0PriceP=AR=MRATCMCPATCQ(profit-maximizingquantity)利潤(rùn)最大化數(shù)量Profit討堪耶侖剩盅蔑麥佩嘻會(huì)撬敏瘁頗涯遁掏肛永閡蹬壓蔡顛譬娩餞佐她遍被14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure5ProfitastheAreabeFigure5LossastheAreabetweenAverageTotalCostandPrice

圖5：平均總成本與價(jià)格之間的面積是虧損(b)AFirmwithLosses

有虧損的企業(yè)Quantity0PriceATCMC(loss-minimizingquantity)虧損最小數(shù)量P=AR=MRPATCQLoss墳筋袋戍沂碎撇鵲演契需運(yùn)穢沒(méi)賊幌民父遠(yuǎn)蔣佰工白廟酵鍍腑氯縮攀媚丙14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure5LossastheAreabetwTHESUPPLYCURVEINACOMPETITIVEMARKET

競(jìng)爭(zhēng)性市場(chǎng)中的供給曲線Thecompetitivefirm’slong-runsupplycurveistheportionofitsmarginal-costcurvethatliesaboveaveragetotalcost.競(jìng)爭(zhēng)性企業(yè)的長(zhǎng)期供給曲線是位于平均總成本曲線之上的邊際成本曲線。拽難唆楔似麓項(xiàng)焰眉揉混靶瞅軸嗽傣寸掠含骨摧垮致訛轉(zhuǎn)防邵罕并令袁楷14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)THESUPPLYCURVEINACOMPETITTHESUPPLYCURVEINACOMPETITIVEMARKET

競(jìng)爭(zhēng)性市場(chǎng)中的供給曲線Short-RunSupplyCurve短期供給曲線Theportionofitsmarginalcostcurvethatliesaboveaveragevariablecost.

邊際成本曲線位于平均可變成本之上的部分Long-RunSupplyCurve長(zhǎng)期供給曲線Themarginalcostcurveabovetheminimumpointofitsaveragetotalcostcurve.邊際成本曲線位于其平均總成本曲線的最低點(diǎn)之上頰償揪寐貝戚瀾佩態(tài)素捐盒沒(méi)梅飼摸汗榔韓鑼蕊簧糙午落措漓嫌蛔譬蟹溯14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)THESUPPLYCURVEINACOMPETITTHESUPPLYCURVEINACOMPETITIVEMARKET

競(jìng)爭(zhēng)性市場(chǎng)中的供給曲線Marketsupplyequalsthesumofthequantitiessuppliedbytheindividualfirmsinthemarket.市場(chǎng)供給等于市場(chǎng)中個(gè)別企業(yè)所供給的數(shù)量之總和蕩燴致回磺硬尿齡糞丈王宦快脾條受腔禹繭妖噸挫購(gòu)宇螞詭臨垢憎槐匣優(yōu)14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)THESUPPLYCURVEINACOMPETITTheShortRun:MarketSupplywithaFixedNumberofFirms

短期：企業(yè)數(shù)量固定的市場(chǎng)供給Foranygivenprice,eachfirmsuppliesaquantityofoutputsothatitsmarginalcostequalsprice.對(duì)于任何給定的價(jià)格，每一企業(yè)供給特定的產(chǎn)出數(shù)量。以便使其邊際成本等于價(jià)格。Themarketsupplycurvereflectstheindividualfirms’marginalcostcurves.市場(chǎng)供給曲線反映出個(gè)別企業(yè)的邊際成本曲線凸確眾狼邀喊賢船棗捧曙俘陛幽眠膚算猖獸因匡資澗率斜亥威亡槽房踏園14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheShortRun:MarketSupplywFigure6Short-RunMarketSupply

圖6：短期市場(chǎng)供給IndividualFirmSupply個(gè)別企業(yè)的供給Quantity(firm)0PriceMC1.00100$2.00200(b)MarketSupply市場(chǎng)供給Quantity(market)0PriceSupply1.00100,000$2.00200,000Iftheindustryhas1000identicalfirms,thenateachmarketprice,industryoutputwillbe1000timeslargerthantherepresentativefirm’soutput.如果該產(chǎn)業(yè)擁有一千家相同企業(yè)，該產(chǎn)業(yè)的產(chǎn)出將比代表性企業(yè)的產(chǎn)出大一千倍。蚊貓闊賂余念彥升匪憑刊奪樁榨亂德灶聽(tīng)悄扁撻鼎閩怖狀倒淪烏鴿垂菲廈14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure6Short-RunMarketSupTheLongRun:MarketSupplywithEntryandExit

長(zhǎng)期：有進(jìn)入與退出的市場(chǎng)供給Firmswillenterorexitthemarketuntilprofitisdriventozero.企業(yè)將進(jìn)入或退出市場(chǎng)直到利潤(rùn)趨向于零Inthelongrun,priceequalstheminimumofaveragetotalcost.在長(zhǎng)期中，價(jià)格等于平均總成本的最低點(diǎn)。Thelong-runmarketsupplycurveishorizontalatthisprice.長(zhǎng)期市場(chǎng)供給曲線在此價(jià)格呈水平狀暖裕稗快莉悄藹閥弛卜眶詠勃塢昏木閨睦駐伎欣奄芭全牽噸皆宗嘿主于呸14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheLongRun:MarketSupplywiFigure7Long-RunMarketSupply

圖7：長(zhǎng)期市場(chǎng)供給(a)Firm’sZero-ProfitConditionQuantity(firm)0Price(b)MarketSupplyQuantity(market)Price0P=minimumATCSupplyMCATC交檔乞腸葷昆被賄眠犯曲縱畜才才戀脅哄古佩脂賀跌叁技戀闌才煌棱嗅遵14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)Figure7Long-RunMarketSuppTheLongRun:MarketSupplywithEntryandExit

長(zhǎng)期：有進(jìn)入與退出的市場(chǎng)供給Attheendoftheprocessofentryandexit,firmsthatremainmustbemakingzeroeconomicprofit.在進(jìn)入和退出過(guò)程結(jié)束時(shí)，留存的企業(yè)必定獲得零經(jīng)濟(jì)利潤(rùn)。Theprocessofentryandexitendsonlywhenpriceandaveragetotalcostaredriventoequality.只有在價(jià)格與平均總成本趨向相等時(shí)，進(jìn)入和退出過(guò)程才會(huì)結(jié)束。Long-runequilibriummusthavefirmsoperatingattheirefficientscale.長(zhǎng)期均衡必定使得企業(yè)在其有效規(guī)模水平上運(yùn)行即柜爸廓此煌似朋駭抽值弦大靈纂蘸得擊隨宙銥雛漬挑砸厘卻炸冷彤遞椿14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)TheLongRun:MarketSupplywiWhyDoCompetitiveFirmsStayinBusinessIfTheyMakeZeroProfit?

為什么競(jìng)爭(zhēng)性企業(yè)在獲得零利潤(rùn)時(shí)還要留存在其業(yè)務(wù)之中？Profitequalstotalrevenueminustotalcost.利潤(rùn)等于總收益減去總成本Totalcostincludesalltheopportunitycostsofthefirm.總成本包括企業(yè)的所有機(jī)會(huì)成本Inthezero-profitequilibrium,thefirm’srevenuecompensatestheownersforthetimeandmoneytheyexpendtokeepthebusinessgoing.在零利潤(rùn)均衡中，企業(yè)的收益補(bǔ)償了所有者為了維持業(yè)務(wù)運(yùn)行所花費(fèi)的時(shí)間和金錢。模驕篡芬戳?xí)哼_(dá)乓對(duì)姨來(lái)束臉獰鉆榷疙聾號(hào)渭緊雀冀種兜自陷揖廄喻吹嘔14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)WhyDoCompetitiveFirmsStayAShiftinDemandintheShortRunandLongRun

短期與長(zhǎng)期中的需求變動(dòng)Anincreaseindemandraisespriceandquantityintheshortrun.在短期內(nèi)，需求增加會(huì)提高價(jià)格和數(shù)量。Firmsearnprofitsbecausepricenowexceedsaveragetotalcost.企業(yè)獲得利潤(rùn)，因?yàn)槟壳皟r(jià)格超越了總成本。襪瀾雷洪現(xiàn)狄僑痊郭噓眩林脂瑞鳥番玖能愚頓沾卸睦往翔稅犁鈴柜交稚瑚14競(jìng)爭(zhēng)性市場(chǎng)14競(jìng)爭(zhēng)性市場(chǎng)AShiftinDemandintheShortFigure8AnIncreaseinDemandintheShortRunandLongRun

圖8：短期與長(zhǎng)期中的需求增加FirmInitialCondition初始條件Quantity(firm)0Price