竞争企业的垄断

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,垄 断,竞争企业是价格接受者，而垄断企业是价格制定者,.,垄断企业,monopoly,. . .,产品的惟一卖者,.,其产品没有相近的替代品,.,产生垄断的原因,垄断的基本原因是进入壁垒,barriers to entry,.,产生垄断的原因,进入壁垒有三个主要来源,:,关键资源由一家企业拥有,.,政府给予一个企业排他性地生产某种产品或劳务的权利,.,生产成本使一个生产者比大量生产者更有效率,.,垄断资源,虽然关键资源的排他性所有权是垄断的潜在原因，但实际上垄断很少产生于这种原因。,.,政府创造的垄断,政府给予一个企业排他性的出售某种物品或劳务的权力，从而产生垄断。,政府创造的垄断,专利和版权法是政府如何为公共利益创造垄断的一个例子。,自然垄断,当一个企业能够以低于两个或更多企业的成本为整个市场供给一种物品或劳务时，这个行业就是自然垄断,natural monopoly,。,自然垄断,当相关产量范围存在规模经济时，自然垄断就产生了。,Figure 1 Economies of Scale as a Cause of Monopoly,Copyright 2004 South-Western,Quantity of Output,Average,total,cost,0,Cost,垄断者如何作出生产与定价决策,垄断与竞争,垄断,Monopoly,惟一的卖者,面临向右下方倾斜的需求曲线,价格制定者,降低价格会增加销售量,竞争企业,Competitive Firm,众多卖者中的一个,面临一条水平需求曲线,价格接受者,在既定价格时想卖多少就卖多少,Figure 2 Demand Curves for Competitive and Monopoly Firms,Copyright 2004 South-Western,Quantity of Output,Demand,(a) A Competitive Firm,s Demand Curve,(b) A Monopolist,s Demand Curve,0,Price,Quantity of Output,0,Price,Demand,垄断者的收益,总收益,P,Q = TR,平均收益,TR/Q = AR = P,边际收益,D,TR/,D,Q = MR,Table 1 A Monopolys Total, Average, and Marginal Revenue,Copyright2004 South-Western,垄断者的收益,垄断者的边际收益,垄断者的边际收益总是少于其物品价格,.,需求曲线向下倾斜,.,为了增加销售量一个垄断企业必须降低其物品 的价格。,这种价格的下降减少了它已经卖出的各单位的收益,垄断者的收益,垄断者的边际收益,垄断者增加它销售的的数量时，总收益,(,P,Q,),有两种效应：,产量效应,The output effect,销售的产量越多，因此,Q,越大。,价格效应,The price effect,价格下降，因此,P,降低。,Figure 3 Demand and Marginal-Revenue Curves for a Monopoly,Copyright 2004 South-Western,Quantity of Water,Price,$11,10,9,8,7,6,5,4,3,2,1,0,1,2,3,4,Demand,(average,revenue),Marginal,revenue,1,2,3,4,5,6,7,8,Figure 4 Profit Maximization for a Monopoly,Copyright 2004 South-Western,Quantity,Q,Q,0,Costs and,Revenue,Demand,Average total cost,Marginal revenue,Marginal,cost,Monopoly,price,Q,MAX,B,1. The intersection of the,marginal-revenue curve,and the marginal-cost,curve determines the,profit-maximizing,quantity . . .,A,2. . . . and then the demand,curve shows the price,consistent with this quantity.,利润最大化,垄断者通过选择边际收益等于边际成本的产量（,A,点,),来实现利润最大化 。,然后可以用需求曲线找出使消费者购买那种数量的价格（,B,点）。,利润最大化,比较垄断者与竞争企业,对于竞争企业，,P = MR = MC,对于垄断企业，,P MR = MC,垄断的利润,利润等于总收益减总成本,.,利润,=,TR,-,TC,利润,= (,TR,/,Q,-,TC,/,Q,),Q,利润,= (,P,-,ATC,),Q,Figure 5 The Monopolists Profit,Copyright 2004 South-Western,Monopoly,profit,Average,total,cost,Quantity,Monopoly,price,Q,MAX,0,Costs and,Revenue,Demand,Marginal cost,Marginal revenue,Average total cost,B,C,E,D,垄断的利润,只要价格高于平均总成本，垄断者就得到经济利润。,Figure 6 The Market for Drugs,Copyright 2004 South-Western,Quantity,0,Costs and,Revenue,Demand,Marginal,revenue,Price,during,patent life,Monopoly,quantity,Price after,patent,expires,Marginal,cost,Competitive,quantity,垄断的福利代价,与竞争企业相反，垄断收取高于边际成本的价格。,从消费者的角度来看，高价格使垄断是不合意的。,然而，从企业的角度看，高价格使垄断极为合意。,消费者剩余,支付意愿：买主愿意为某种物品支付的最高量。,衡量买者对物品的评价,消费者剩余：买者的支付意愿减买主的实际支付量。,消费者剩余衡量买者参与市场的利益,需求曲线给出的价格表示边际买主的支付意愿,需求曲线以下和价格以上的面积衡量市场的消费者剩余,生产者剩余,成本：卖者为了生产一种物品必须放弃的每种东西的价值。,生产者剩余：卖者得到的量减生产成本。,生产者剩余衡量卖者参与市场的利益。,供给曲线给出的价格表示边际卖者的成本,价格之下和供给曲线以上的面积衡量市场 的生产者剩余,总剩余,消费者和生产者剩余的总和,衡量社会的经济福利,消费者剩余买者的评价买者支付的量,生产者剩余卖者得到的量卖者的成本,总剩余买者的评价买者支付的量卖者得到的量卖者的成本,总剩余买者的评价卖者的成本,Figure 7 The Efficient Level of Output,Copyright 2004 South-Western,Quantity,0,Price,Demand,(value to buyers),Marginal cost,Value to buyers,is greater than,cost to seller.,Value to buyers,is less than,cost to seller.,Cost,to,monopolist,Cost,to,monopolist,Value,to,buyers,Value,to,buyers,Efficient,quantity,无谓损失,The Deadweight Loss,由于垄断者通过收取高于边际成本的价格发挥其市场势力，它在消费者的支付意愿和生产者成本之间打入了一个楔子。,楔子使销售量低于社会最适水平。,Figure 8 The Inefficiency of Monopoly,Copyright 2004 South-Western,Quantity,0,Price,Deadweight,loss,Demand,Marginal,revenue,Marginal cost,Efficient,quantity,Monopoly,price,Monopoly,quantity,无谓损失,垄断的无效率,垄断者生产的产量小于社会有效率的产量,无谓损失,垄断引起的无谓损失类似于税收引起的无谓损失,.,二者之间的区别是政府得到了税收的收入，而私人企业得到了垄断利润,.,对垄断的公共政策,政府决策者会以四种方式中的一种对垄断问题做出反应：,努力使垄断行业更有竞争性,.,管制垄断者的行为,.,把一些私人垄断变为公共企业,.,无所作为,.,用反托拉斯法增强竞争,反托拉斯法是遏制垄断权力的法律集成,.,反托拉斯法给予政府促进竞争的各种方法,.,这些法律允许政府阻止合并,.,允许政府分解公司,.,禁止公司以使市场竞争减弱的方法协调他们的活动,.,管制,政府管制垄断者收取的价格,.,如果价格等于边际成本，资源配置将是有效的,.,Figure 9 Marginal-Cost Pricing for a Natural Monopoly,Copyright 2004 South-Western,Loss,Quantity,0,Price,Demand,Average total cost,Regulated,price,Marginal cost,Average total,cost,管制,实际上，管制者解决这一问题的方法是允许垄断者从降低成本中以更高利润的形式得到一些利益，这种做法要求对边际成本定价的某种背离。,公有制,Public Ownership,政府管制的不是由私人企业经营的自由垄断，而是自己经营自然垄断。,无所作为,如果“市场失灵”小于公共政策的不完善所引起的“政治失灵”，则政府最好什么都不作。,价格歧视,价格歧视,Price discrimination,：,以不同价格向不同顾客出售同一种物品的经营做法,价格歧视,当一种物品在竞争市场上出售时，实行价格歧视是不可能的，因为有许多以市场价格出售同一种物品的企业。要实行价格歧视，该企业必然有某种市场势力。,.,完全价格歧视,Perfect Price Discrimination,指垄断者完全了解每个顾客的支付意愿，并对每个顾客收取不同价格的情况,.,价格歧视,价格歧视的的两个重要结果：,增加了垄断者利润,.,减少了无谓损失,Figure 10 Welfare with and without Price Discrimination,Copyright 2004 South-Western,Profit,(a) Monopolist with Single Price,Price,0,Quantity,Deadweight,loss,Demand,Marginal,revenue,Consumer,surplus,Quantity sold,Monopoly,price,Marginal cost,Figure 10 Welfare with and without Price Discrimination,Copyright 2004 South-Western,Profit,(b) Monopolist with Perfect Price Discrimination,Price,0,Quantity,Demand,Marginal cost,Quantity sold,PRICE DISCRIMINATION,价格歧视的例子,电影票,飞机票价,折扣券,奖学金,数量折扣,结论：垄断的普遍性,垄断问题有多普遍,?,垄断是常见的。,大多数企业对他们收取的价格都有某种控制。,有相当大垄断势力的企业是很少的,.,只有少数物品是真正独一无二的。,Summary,A monopoly is a firm that is the sole seller in its market.,It faces a downward-sloping demand curve for its product.,A monopolys marginal revenue is always below the price of its good.,Summary,Like a competitive firm, a monopoly maximizes profit by producing the quantity at which marginal cost and marginal revenue are equal.,Unlike a competitive firm, its price exceeds its marginal revenue, so its price exceeds marginal cost.,Summary,A monopolists profit-maximizing level of output is below the level that maximizes the sum of consumer and producer surplus.,A monopoly causes deadweight losses similar to the deadweight losses caused by taxes.,Summary,Policymakers can respond to the inefficiencies of monopoly behavior with antitrust laws, regulation of prices, or by turning the monopoly into a government-run enterprise.,If the market failure is deemed small, policymakers may decide to do nothing at all.,Summary,Monopolists can raise their profits by charging different prices to different buyers based on their willingness to pay.,Price discrimination can raise economic welfare and lessen deadweight losses.,