精选Chap14竞争市场中的企业48课件.ppt

1、Firms in Competitive Markets竞争市场中的企业竞争市场中的企业Chapter 14Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.WHAT IS A COMPETITIVE MARKET?uA perfectly competitive market has the following characteristics:uThere are many buyers and sellers in the market.uThe goods offered by the various

2、sellers are largely the same.uFirms can freely enter or exit the market.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.什么是竞争市场？什么是竞争市场？u完全竞争市场完全竞争市场有以下特点有以下特点:u市场中有许多买者和许多卖者。市场中有许多买者和许多卖者。u各个卖者所提供的物品大体上是相同的。各个卖者所提供的物品大体上是相同的。u企业可以自由地进入或退出市场。企业可以自由地进入或退出市场。Harcourt,Inc.items and

3、derived items copyright 2001 by Harcourt,Inc.WHAT IS A COMPETITIVE MARKET?uAs a result of its characteristics,the perfectly competitive market has the following outcomes:uThe actions of any single buyer or seller in the market have a negligible impact on the market price.neach buyer and seller is a

4、price taker.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.什么是竞争市场？什么是竞争市场？u由于以上特点由于以上特点,完全竞争市场完全竞争市场 具有以下具有以下结果结果:u市场上任何一个买者或卖者的行动对市市场上任何一个买者或卖者的行动对市场价格的影响都可以忽略不计。场价格的影响都可以忽略不计。u每一个买者和卖者都是价格的接受者每一个买者和卖者都是价格的接受者Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.

5、The Revenue of a Competitive Firm竞争企业的收益竞争企业的收益Total revenue for a firm is the selling price times the quantity sold.一个企业的一个企业的总收益总收益等于销售价格乘等于销售价格乘以销售量。以销售量。TR=(P X Q)Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.The Revenue of a Competitive FirmnAverage revenue tells us how mu

6、ch revenue a firm receives for the typical unit sold.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.The Revenue of a Competitive FirmIn perfect competition,average revenue equals the price of the good.Average revenue=Total revenueQuantity=(PriceQuantity)Quantity=Price Harcourt,I

7、nc.items and derived items copyright 2001 by Harcourt,Inc.The Revenue of a Competitive Firm竞争企业的收益竞争企业的收益Marginal revenue is the change in total revenue from an additional unit sold.边际收益边际收益是增加一个单位销售量是增加一个单位销售量所引起的总收益变化。所引起的总收益变化。MR=TR/QHarcourt,Inc.items and derived items copyright 2001 by Harcourt

8、,Inc.The Revenue of a Competitive Firm竞争企业的收益竞争企业的收益For competitive firms,marginal revenue equals the price of the good.对竞争企业来说，对竞争企业来说，边际收益边际收益等于等于物品的销售价格。物品的销售价格。Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.表表1.竞争企业的总收益、平均收益和边际收益竞争企业的总收益、平均收益和边际收益销量销量(Q)价格价格(P)总收益总收益(TR=PxQ)

9、平均收益平均收益(AR=TR/Q)边际收益边际收益(MR=)1$6.00$6.00$6.002$6.00$12.00$6.00$6.003$6.00$18.00$6.00$6.004$6.00$24.00$6.00$6.005$6.00$30.00$6.00$6.006$6.00$36.00$6.00$6.007$6.00$42.00$6.00$6.008$6.00$48.00$6.00$6.00QTR/Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.Profit Maximization and the

10、Competitive Firms Supply CurveuThe goal of a competitive firm is to maximize profit.uThis means that the firm will want to produce the quantity that maximizes the difference between total revenue and total cost.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.利润最大化与竞争企业的供给曲线利润最大化与

11、竞争企业的供给曲线u竞争企业的目标是竞争企业的目标是利润最大化。利润最大化。u这就意味着企业想生产某一产量，这就意味着企业想生产某一产量，使总收益与总成本的差最大。使总收益与总成本的差最大。Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.表表2.利润最大化利润最大化:一个数字例子一个数字例子价格价格(P)销量销量(Q)总收益总收益(TR=PxQ)总成本总成本(TC)利润利润(TR-TC)边际收益边际收益(MR=)边际成本边际成本MC=利润变化利润变化MR-MC0$0.00$3.00-$3.00$6.001$

12、6.00$5.00$1.00$6.00$2.00$4$6.002$12.00$8.00$4.00$6.00$3.00$3$6.003$18.00$12.00$6.00$6.00$4.00$2$6.004$24.00$17.00$7.00$6.00$5.00$1$6.005$30.00$23.00$7.00$6.00$6.00$0$6.006$36.00$30.00$6.00$6.00$7.00($1)$6.007$42.00$38.00$4.00$6.00$8.00($2)$6.008$48.00$47.00$1.00$6.00$9.00($3)Figure 1 Profit Maximiza

13、tion for a Competitive FirmCopyright 2004 South-WesternQuantity0CostsandRevenueMCATCAVCMC1Q1MC2Q2The firm maximizesprofit by producing the quantity at whichmarginal cost equalsmarginal revenue.QMAX P=MR1=MR2 P=AR=MRHarcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.Profit Maximizati

14、on for the Competitive Firm竞争企业的利润最大化竞争企业的利润最大化Profit maximization occurs at the quantity where marginal revenue equals marginal cost.当边际收益等于边际成本时，企业实当边际收益等于边际成本时，企业实现现利润最大化。利润最大化。Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.Profit Maximization for the Competitive FirmWhen MR

15、MC increase QWhen MR MC decrease QWhen MR=MC Profit is maximized.Figure 2 Marginal Cost as the Competitive Firms Supply CurveQuantity0PriceMCATCAVCP1Q1P2Q2This section of thefirms MC curve isalso the firms supplycurve.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.The Firms Shor

16、t-Run Decision to Shut Down（停止营业）（停止营业）uA shutdown refers to a short-run decision not to produce anything during a specific period of time because of current market conditions.uExit refers to a long-run decision to leave the market.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.

17、企业的短期停止营业决策企业的短期停止营业决策u停止营业停止营业是指在某个特殊时期由是指在某个特殊时期由于当前的市场条件而不生产任何于当前的市场条件而不生产任何东西的短期决策。东西的短期决策。u退出退出 是指离开市场的长期决策。是指离开市场的长期决策。Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.The Firms Short-Run Decision to Shut DownThe firm considers its sunk costs when deciding to exit,but ignore

18、s them when deciding whether to shut down.uSunk costs are costs that have already been committed and cannot be recovered.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.企业的短期停止营业决策企业的短期停止营业决策 当决定退出时，企业考虑当决定退出时，企业考虑沉淀沉淀成本；成本；当决定是否停止营业时企业当决定是否停止营业时企业应忽略沉淀成本。应忽略沉淀成本。u沉淀成本沉淀成本 是已经发生而

19、且无法收回是已经发生而且无法收回（并与当前决策无关）（并与当前决策无关）的成本。的成本。Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.The Firms Short-Run Decision to Shut DownuThe firm shuts down if the revenue it gets from producing is less than the variable cost of production.Shut down if TR VC Shut down if P AVCHarcou

20、rt,Inc.items and derived items copyright 2001 by Harcourt,Inc.企业的短期停止营业决策企业的短期停止营业决策u如果生产能得到的收益小于生产的可变如果生产能得到的收益小于生产的可变成本，企业就停止营业。成本，企业就停止营业。如果如果 TR VC，停止营业。停止营业。如果如果 P AVC，停止营业。停止营业。Figure 3 The Competitive Firms Short Run Supply CurveMCQuantityATCAVC0CostsFirmshutsdown ifP AVC,firm will continue t

21、o produce in the short run.If P ATC,the firm will continue to produce at a profit.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.The Firms Long-Run Decision to Exit or Enter a MarketuIn the long-run,the firm exits if the revenue it would get from producing is less than its total

22、 cost.Exit if TR TC Exit if P ATCHarcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.企业进入或退出一个市场的长期决策企业进入或退出一个市场的长期决策u在长期中，如果从生产中得到的收益小在长期中，如果从生产中得到的收益小于生产的总成本于生产的总成本,企业就退出。企业就退出。如果如果 TR TC，就退出。就退出。如果如果 P TC Enter if P ATCHarcourt,Inc.items and derived items copyright 2001 by Harcour

23、t,Inc.利润利润Q图图5.作为价格与平均总成本之间面积的利润作为价格与平均总成本之间面积的利润产量产量0价格价格P =AR=MRATCMCPATC利润最大化产量利润最大化产量a.有利润企业有利润企业 新企业进入市场新企业进入市场 Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.亏损亏损图图5.作为价格与平均总成本之间面积的利润作为价格与平均总成本之间面积的利润产量产量0价格价格P =AR=MRATCMCPQ亏损最小化产量亏损最小化产量ATCb.亏损企业亏损企业 退出市场退出市场Figure 7 Mark

24、et Supply with Entry and Exit(a)Firms Zero-Profit ConditionQuantity(firm)0Price(b)Market SupplyQuantity(market)Price0P=minimumATCSupplyMCATCHarcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.The Long Run:Market Supply with Entry and ExituFirms will enter or exit the market until pro

25、fit is driven to zero.uIn the long run,price equals the minimum of average total cost.uThe long-run market supply curve is horizontal at this price.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.长期：有进入与退出的市场供给长期：有进入与退出的市场供给u企业进入或退出市场，直到经济企业进入或退出市场，直到经济利润为零。利润为零。u在长期中，价格等于最小平均总在长

26、期中，价格等于最小平均总成本。成本。u长期市场供给曲线是这一价格时长期市场供给曲线是这一价格时的水平线。的水平线。Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.The Long Run:Market Supply with Entry and ExituLong-run equilibrium must have firms operating at their efficient scale.u竞争市场长期均衡一定是企业在其有效竞争市场长期均衡一定是企业在其有效规模时运行。规模时运行。Harcourt,

27、Inc.items and derived items copyright 2001 by Harcourt,Inc.Why Do Competitive Firms Stay in Business If They Make Zero Profit?uProfit equals total revenue minus total cost.uTotal cost includes all the opportunity costs of the firm.uIn the zero-profit equilibrium,the firms revenue compensates the own

28、ers for the time and money they expend to keep the business going.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.如果竞争企业获得零利润，为什么它们还在经营？如果竞争企业获得零利润，为什么它们还在经营？u利润等于总收益减总成本。利润等于总收益减总成本。u总成本包括企业的所有机会成本。总成本包括企业的所有机会成本。u在零利润均衡时，企业的收益应该补在零利润均衡时，企业的收益应该补偿所有者期望用于使其企业维持的时偿所有者期望用于使其企业维持的时间

29、和金钱。间和金钱。Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.nMarginal Firm 边际企业边际企业The marginal firm is the firm that would exit the market if the price were any lower.边际企业边际企业如果价格有任何下降就退如果价格有任何下降就退出市场的企业。出市场的企业。Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.Sum

30、maryuBecause a competitive firm is a price taker,its revenue is proportional to the amount of output it produces.uThe price of the good equals both the firms average revenue and its marginal revenue.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.小结小结u因为竞争企业是价格接受者，所因为竞争企业是价格接受者，所

31、以它的收益与产量是同比例的。以它的收益与产量是同比例的。u物品的价格等于企业的平均收益物品的价格等于企业的平均收益和边际收益。和边际收益。Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.SummaryuTo maximize profit a firm chooses the quantity of output such that marginal revenue equals marginal cost.uThis is also the quantity at which price equals m

32、arginal cost.uTherefore,the firms marginal cost curve is its supply curve.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.小结小结u为了利润最大化，企业选择使边际为了利润最大化，企业选择使边际收益等于边际成本的产量。收益等于边际成本的产量。u这一产量也是价格等于边际成本的这一产量也是价格等于边际成本的产量。产量。u因此，企业的边际成本曲线就是它因此，企业的边际成本曲线就是它的供给曲线。的供给曲线。Harcourt,Inc.items

33、and derived items copyright 2001 by Harcourt,Inc.SummaryuIn the short run when a firm cannot recover its fixed costs,the firm will choose to shut down temporarily if the price of the good is less than average variable cost.uIn the long run when the firm can recover both fixed and variable costs,it w

34、ill choose to exit if the price is less than average total cost.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.小结小结u在短期中，当企业不能收回其固定成本在短期中，当企业不能收回其固定成本时，如果物品价格小于平均可变成本，时，如果物品价格小于平均可变成本，企业将选择停止营业。企业将选择停止营业。u在长期中，如果价格小于平均总成本，在长期中，如果价格小于平均总成本，企业不能收回其固定成本和可变成本，企业不能收回其固定成本和可变成本，企业将选择退

35、出市场。企业将选择退出市场。Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.SummaryuIn a market with free entry and exit,profits are driven to zero in the long run and all firms produce at the efficient scale.Harcourt,Inc.items and derived items copyright 2001 by Harcourt,Inc.小结小结u在可以自由进入与退出的市场中，长在可以自由进入与退出的市场中，长期利润为零，所有企业在有效规模时期利润为零，所有企业在有效规模时生产。生产。