不完全竞争市场的类型 Types of Imperfectly 垄断竞争 Competitive Markets Monopolistic ◆垄断竞争 Monopolistic Competition Competition ◆许多企业出售类似但不相同的产品 Many firms selling products that are similar but not identical 第17章 寡头 Oligopoly Chapter 17 只有少数卖主,每一个提供类似的或相同的 Only a few sellers, each offering a similar or identical product to the others 垄断竞争的特征 垄断竞争 Attributes of Monopolistic Monopolistic Competition Competition ◆许多卖者 市场具有某些竞争的特性也具 Many sellers 有某些垄断的特性。 ◆产品差别 Markets that have some Product differentiation features of competition and ◆自由进入和退出 some features of monopoly. Free entry and exit 许多卖者 产品差别 Many Sellers Product differentiation 有许多企业争夺同样的顾客群体 There are many firms competing for the same 产的产出有单简品至少与其他企业 ◆举例:书箱、CD、电影、电脑游戏、餐馆、 Each firm produces a product that is at 钢琴课、点心、家具等 least slightly different from those of other firms Product examples include books, CDs, movies, computer games, restaurants, piano lessons, ◆每个企业不是价格接受者,而是面临 条向右下方倾斜的需求曲线 )5 Rather than being a price taker, each firm faces a downward-sloping demand
1 垄断竞争 Monopolistic Competition 第17章 Chapter 17 2 不完全竞争市场的类型 Types of Imperfectly Competitive Markets 垄断竞争 Monopolistic Competition 许多企业出售类似但不相同的产品。 Many firms selling products that are similar but not identical. 寡头 Oligopoly 只有少数卖主，每一个提供类似的或相同的 产品。 Only a few sellers, each offering a similar or identical product to the others. 3 垄断竞争 Monopolistic Competition 市场具有某些竞争的特性也具 有某些垄断的特性。 Markets that have some features of competition and some features of monopoly. 4 垄断竞争的特征 Attributes of Monopolistic Competition 许多卖者 Many sellers 产品差别 Product differentiation 自由进入和退出 Free entry and exit 5 许多卖者 Many Sellers 有许多企业争夺同样的顾客群体。 There are many firms competing for the same group of customers. 举例：书籍、 CD、电影、电脑游戏、餐馆、 钢琴课、点心、家具等 Product examples include books, CDs, movies, computer games, restaurants, piano lessons, cookies, furniture, etc. 6 产品差别 Product Differentiation 每一个企业生产的产品至少与其他企业 生产的产品略有不同。 Each firm produces a product that is at least slightly different from those of other firms. 每个企业不是价格接受者，而是面临一 条向右下方倾斜的需求曲线。 Rather than being a price taker, each firm faces a downward-sloping demand curve
自由进入和退出 短期中的垄断竞争企业 Free Entry or Exit Monopolistic Competitors in the short Run ◆企业可以没有限制地进入和退出一个市场。 Firms can enter or exit the market without a)企业有利润 Firm Makes a profit restriction ◆市场上企业的数目要一直调整到经济利润为 零时为止 The number of firms in the market adjusts until economic profits are zero. 平均总取本Aver y众公 利润 Profi 需求 Demand 利化产 maximizing quantity 短期中的老断竞争企业 长期中的垄断竞争企业 Monopolistic Competitors in Monopolistic Competition in the short Run the Long ri b)企业有亏损 ATC Firm Makes Losses 短期经济利涧敢励新企业进入市场。这导致 Short-run economic profits encourage new firms to enter 损 Losses the market. Thi 平均总成本 Average 黄加产品提供的数目。 Increases the number of products offered ◆减少已在市场中的企业面临的需求 Reduces demand faced by firms already in the market. ◆已有企业面临的需求曲线向左移动 需求 Demand Incumbent firms' demand curves shift to the left. 随着已有企业的产品需求的减少,这些企业的利润下降 号不化 profits decline. 长期中的垄断竞争企业 Monopolistic Competition in the Long Run 长期均衡 短期经济亏损鼓励企业退出市场。这导致: The Long- Run Equilibrium Short-run economic losses encourage firms to exit th market. This ◆减少产品提供的数目。 企业进入和退出直到市场上的 Decreases the number of products offered. 企业正好有零经济利润为止 ◆增加仍在市场中的企业面临的需求 Inereases demand faced by the remaining firms. Firms will enter and exit until ◆剩余的企业面临的需求曲线向右移动。 the firms are making exactly Shifts the remaining firms' demand curves to the right. zero economic profits. ●增加剩余企业的利润。 ncreases the remaining firms' profits
2 7 自由进入和退出 Free Entry or Exit 企业可以没有限制地进入和退出一个市场。 Firms can enter or exit the market without restriction. 市场上企业的数目要一直调整到经济利润为 零时为止。 The number of firms in the market adjusts until economic profits are zero. 8 短期中的垄断竞争企业 Monopolistic Competitors in the Short Run... (a) 企业有利润 Firm Makes a Profit Quantity 0 Price 需求Demand MR ATC 利润Profit MC 利润最大化产量 Profitmaximizing quantity 价格Price 平均总成本Average total cost 9 短期中的垄断竞争企业 Monopolistic Competitors in the Short Run... 0 Quantity Price 需求Demand MR 亏损Losses (b) 企业有亏损 Firm Makes Losses MC ATC 平均总成本Average total cost 亏损最小化产量 Loss- minimizing quantity 价格Price 10 长期中的垄断竞争企业 Monopolistic Competition in the Long Run 短期经济利润鼓励新企业进入市场。这导致： Short-run economic profits encourage new firms to enter the market. This: 增加产品提供的数目。 Increases the number of products offered. 减少已在市场中的企业面临的需求。 Reduces demand faced by firms already in the market. 已有企业面临的需求曲线向左移动。 Incumbent firms’ demand curves shift to the left. 随着已有企业的产品需求的减少，这些企业的利润下降。 Demand for the incumbent firms’ products fall, and their profits decline. 11 长期中的垄断竞争企业 Monopolistic Competition in the Long Run 短期经济亏损鼓励企业退出市场。这导致： Short-run economic losses encourage firms to exit the market. This: 减少产品提供的数目。 Decreases the number of products offered. 增加仍在市场中的企业面临的需求。 Increases demand faced by the remaining firms. 剩余的企业面临的需求曲线向右移动。 Shifts the remaining firms’ demand curves to the right. 增加剩余企业的利润。 Increases the remaining firms’ profits. 12 长期均衡 The Long-Run Equilibrium 企业进入和退出直到市场上的 企业正好有零经济利润为止。 Firms will enter and exit until the firms are making exactly zero economic profits
长期中的垄断竞争企业 A Monopolistic Competitor 长期均衡的两大特征 in the Long Run. Two Characteristics of Long- Price Run Equilibrium ☆正如在垄断情况一样,价格大于边际成本。 As in a monopoly, price exceeds marginal cost. ◆利润最大化要求边际收益等于边际成本 PEATC Profit maximization requires marginal revenue to equal marginal cost. ◆向下倾斜的需求曲线使边际收益小于价格。 The downward-sloping demand curve makes 需求 Demand marginal revenue less than pric 利满最大化产量 Quantity 长期均衡的两大特征 Two Characteristics of Long 垄断竞争与完全竞争 Run Equilibrium Monopolistic versus Perfect Competition ☆正如在竞争市场上一样,价格等于平均总成本 in a competitive market, 垄断竞争和完全竞争之间有两个值 average total cost. 得注意的差别一生产能力过剩和价 ◆自由进入和退出使经济利润为零 格加成 Free entry and exit drive economic profit to zero There are two noteworthy differences between monopolistic and perfect competition-excess capacity and markup. 生产能力过剩 生产能力过剩 Excess Capacity Excess Capacity ◆在完全竞争市场中,在长期中没有生产能力 ◆在垄断竞争市场中,在长期中有生产 There is no excess capacity in perfect There is excess capacity in competition in the lor ne run monopolistic competition in the long 牌进>褪龛金伞的效模 总成本最小 run Free entry results in competitive firms ◆在垄断竞争中,产量小于有效规模 producing at the point where average total In monopolistic competition, output is cost is minimized. which is the efficient scale less than the efficient scale of perfect of the firm competition
3 13 长期中的垄断竞争企业 A Monopolistic Competitor in the Long Run... Quantity Price 0 需求Demand MR ATC MC 利润最大化产量 Profit-maximizing quantity P=ATC 14 长期均衡的两大特征 Two Characteristics of LongRun Equilibrium 正如在垄断情况一样，价格大于边际成本。 As in a monopoly, price exceeds marginal cost. 利润最大化要求边际收益等于边际成本。 Profit maximization requires marginal revenue to equal marginal cost. 向下倾斜的需求曲线使边际收益小于价格。 The downward-sloping demand curve makes marginal revenue less than price. 15 长期均衡的两大特征 Two Characteristics of LongRun Equilibrium 正如在竞争市场上一样，价格等于平均总成本 As in a competitive market, price equals average total cost. 自由进入和退出使经济利润为零。 Free entry and exit drive economic profit to zero. 16 垄断竞争与完全竞争 Monopolistic versus Perfect Competition 垄断竞争和完全竞争之间有两个值 得注意的差别— 生产能力过剩和价 格加成。 There are two noteworthy differences between monopolistic and perfect competition—excess capacity and markup. 17 生产能力过剩 Excess Capacity 在完全竞争市场中，在长期中没有生产能力 过剩。 There is no excess capacity in perfect competition in the long run. 自由进入使得竞争企业生产平均总成本最小 的产量，这也是企业的有效规模。 Free entry results in competitive firms producing at the point where average total cost is minimized, which is the efficient scale of the firm. 18 生产能力过剩 Excess Capacity 在垄断竞争市场中，在长期中有生产 能力过剩。 There is excess capacity in monopolistic competition in the long run. 在垄断竞争中，产量小于有效规模。 In monopolistic competition, output is less than the efficient scale of perfect competition
生产力过剩 高于边际成本的价格加成 Excess Capacity. Markup Over Marginal Cost a)争 erfectly competitive月 ◆对竞争企业来说,价格等于边际成本 For a competitive firm, price equals marginal cost ◆对垄断竞争企业来说,价格高于边际 成本。 For a monopolistically competitive m, price exceeds marginal cos Quantity produced scale produced scal 高于边际成本的价格加成 高于边际成本的价格加成 Markup Over Marginal Cost. Markup Over Marginal Cost ctly Competitive Firm 由于价格高于边际成本,对垄断竞争 价薇加 企业来说,以牌价多销售出额外的一 单位产品就意味着利润多了 Because price exceeds marginal cost, an extra unit sold at the posted price 求 Demand means more profit for the monopolistically competitive firm Quantity 者航竞争与完全竞争 Monopolistic versus Perfect 垄断竞争与社会福利 Competition. Monopolistic Competition and (a) Monopolistically Competitive Firm (b)Perfectly Competitive Firm the Welfare of Society 指如浪 垄断竞争并不具备所有完全竞争下的 合意的性质。 Monopolistic competition does not have all the desirable properties of perfect competition Excess capacity
4 19 生产能力过剩... Excess Capacity... Quantity (a) 垄断竞争 Monopolistically Competitive Firm (b) 完全竞争 Perfectly Competitive Firm Quantity Price P = MR (需求曲线 demand curve) MC ATC Price 需求 Demand MC ATC 生产能力过剩 Excess capacity 产量 Quantity produced 有效规模 Efficient scale P = MC 产量 Quantity produced = 有效规模 Efficient scale P MR 20 高于边际成本的价格加成 Markup Over Marginal Cost 对竞争企业来说，价格等于边际成本 For a competitive firm, price equals marginal cost. 对垄断竞争企业来说，价格高于边际 成本。 For a monopolistically competitive firm, price exceeds marginal cost. 21 高于边际成本的价格加成 Markup Over Marginal Cost 由于价格高于边际成本，对垄断竞争 企业来说，以牌价多销售出额外的一 单位产品就意味着利润多了。 Because price exceeds marginal cost, an extra unit sold at the posted price means more profit for the monopolistically competitive firm. 22 高于边际成本的价格加成... Markup Over Marginal Cost... Quantity (a) 垄断竞争 Monopolistically Competitive Firm (b) 完全竞争 Perfectly Competitive Firm Quantity Price P = MC P = MR (需求曲线 demand curve) MC ATC 产量 Quantity produced Price P 需求Demand 边际成本 Marginal cost MC ATC MR 价格加成 Markup 产量 Quantity produced 23 垄断竞争与完全竞争 Monopolistic versus Perfect Competition... Quantity (a) Monopolistically Competitive Firm (b) Perfectly Competitive Firm Quantity Price P = MR (demand curve) MC ATC 产量Quantity produced 有效规模 Efficient scale Price P Demand MC ATC P = MC 过剩生产能力 Excess capacity 边际成本 Marginal cost 价格加成 Markup MR 产量Quantity produced =有效规模Efficient scale 24 垄断竞争与社会福利 Monopolistic Competition and the Welfare of Society 垄断竞争并不具备所有完全竞争下的 合意的性质。 Monopolistic competition does not have all the desirable properties of perfect competition
垄断竞争与社会福利 垄断竞争与社会福利 Monopolistic Competition and Monopolistic Competition and the Welfare of Society the Welfare of Society ◆由于高于边际成本的价格加成,垄断竞争有茔断定价 的标准的无调损失 垄断竞争可能引起社会无效率的另一个方面 ere is the normal deadweight loss of monopoly pricing in monopolistic competition caused by the 是,市场上的企业数目可能并不是“理想”的 markup of price over marginal cost. 数目。可能有太多或太少的进入。 ◆但是,若管制所有生产有差别产品的企业,行政管理 Another way in which monopolistic 负担将是巨大的 However, the administrative burden of regulating the competition may be socially inefficient is that pricing of all firms that produce differentiated the number of firms in the market may not be the "ideal" one. There may be too much too little entr 垄断竞争与社会福利 垄断竞争与社会福利 Monopolistic Competition and Monopolistic Competition and the Welfare of Society the Welfare of Society 与进入相关的外部性包括 品多样化外部性:由于消费者从新产品 Externalities of entry include: 引进中得到了一些消费者剩余,所以存在 ◆产品多样化的外部性 与进入相关的正外部性。 product-variety externalities. The product-variety externality: Because ◆抢走生意的外部性。 consumers get some consumer surplus business-stealing externalities. from the introduction of a new product, entry of a new firm conveys a positive externality on consumers. 垄断竞争与社会福利 做广告 Monopolistic Competition and Advertising the elfare of Society 当企业销售有差别产品,并收取高于边阿 抢走生意的外部性:由于其他企业从新竞 成本的价格时,每个企业都有激励以做广 争者进入中失去顾客和利润,所以存在与 进入相关的负外部性 告来吸引更多购买自己特殊产品的买者。 The business-stealing externality: Because When firms sell differentiated products ther firms lose customers and profits from and charge prices above marginal cost, the entry of a new competitor, entry of a each firm has an incentive to advertise in new firm imposes a negative externality on order to attract more buyers to its existing firms. particular product
5 25 垄断竞争与社会福利 Monopolistic Competition and the Welfare of Society 由于高于边际成本的价格加成，垄断竞争有垄断定价 时的标准的无谓损失。 There is the normal deadweight loss of monopoly pricing in monopolistic competition caused by the markup of price over marginal cost. 但是，若管制所有生产有差别产品的企业，行政管理 负担将是巨大的。 However, the administrative burden of regulating the pricing of all firms that produce differentiated products would be overwhelming. 26 垄断竞争与社会福利 Monopolistic Competition and the Welfare of Society 垄断竞争可能引起社会无效率的另一个方面 是，市场上的企业数目可能并不是“理想”的 数目。可能有太多或太少的进入。 Another way in which monopolistic competition may be socially inefficient is that the number of firms in the market may not be the “ideal” one. There may be too much or too little entry. 27 垄断竞争与社会福利 Monopolistic Competition and the Welfare of Society 与进入相关的外部性包括： Externalities of entry include: 产品多样化的外部性。 product-variety externalities. 抢走生意的外部性。 business-stealing externalities. 28 垄断竞争与社会福利 Monopolistic Competition and the Welfare of Society 产品多样化外部性：由于消费者从新产品 引进中得到了一些消费者剩余，所以存在 与进入相关的正外部性。 The product-variety externality: Because consumers get some consumer surplus from the introduction of a new product, entry of a new firm conveys a positive externality on consumers. 29 垄断竞争与社会福利 Monopolistic Competition and the Welfare of Society 抢走生意的外部性：由于其他企业从新竞 争者进入中失去顾客和利润，所以存在与 进入相关的负外部性。 The business-stealing externality: Because other firms lose customers and profits from the entry of a new competitor, entry of a new firm imposes a negative externality on existing firms. 30 做广告 Advertising 当企业销售有差别产品，并收取高于边际 成本的价格时，每个企业都有激励以做广 告来吸引更多购买自己特殊产品的买者。 When firms sell differentiated products and charge prices above marginal cost, each firm has an incentive to advertise in order to attract more buyers to its particular product
做广告 做广告 Advertising Advertising ◆销售高度有差别的消费品的企业通常把收益的 ◆广告的批评者认为,企业做广告是为了操纵人 10%-20% Firms that sell highly differentiated consumer goods typically spend between 10 and 20 Critics of advertising argue that firms advertise percent of revenue on advertising. in order to manipulate people's tastes 然类因若高美党克出点企业收益 ◆他们还认为,广告抑制了竞争,因为广告努力 使人们相信,产品差别大于实际情况 Overall, about 2 percent of total revenue, or They also argue that it impedes competition by over $100 billion a year, is spent on advertising implying that products are more different than they truly ar 做广告 Advertising 品牌 Brand Names ◆广告的辩护者认为,广告给消费者提供了信息。 Defenders argu to consumers 告加剧了竞争,因为它提供了产品和价 ◆批评者认为,品牌使消费者感觉到的差 别大于实际存在的差别 They also argue that advertising increases competition Crities argue that brand names cause by offering a greater variety of products and prices. consumers to perceive differences that do ◆企业花费广告费用的盒愿可以是向消费者发出有关它的 not really exist. 品的质量信号 The willingness of a firm to spend advertising dollars an be a signal to consumers about the quality of the 总结 品牌 Summary Brand names 别产書新音金走有三个特征许多企业,差 ◆经济学家认为,品牌是消费者保证他们购买的 A monopolistically competitive market is 物品高质量的一种有用方法 characterized by three attributes: many firms, Economists have argued that brand names may differentiated products, and free entry. be a useful way for consumers to ensure that the ◆垄断竞争市场的均衡不同于完全竞争之处在于 goods they are buying are of high quality 每个企业有超额生产能力和收取高于边际成 本的价格 ◆品牌向消费者提供了质量信息 The equilibrium in a monopolistically ◆品牌向企业提供了保持高质量的激励。 competitive market differs from perfect competition in that each firm has excess giving firms incentive to maintain high quality capacity and each firm charges a price above marginal cost
6 31 做广告 Advertising 销售高度有差别的消费品的企业通常把收益的 10%-20%用于做广告。 Firms that sell highly differentiated consumer goods typically spend between 10 and 20 percent of revenue on advertising. 就美国整体经济而言，广告支出占企业总收益 的2%左右，或在1000亿美元以上。 Overall, about 2 percent of total revenue, or over $100 billion a year, is spent on advertising. 32 做广告 Advertising 广告的批评者认为，企业做广告是为了操纵人 们的嗜好。 Critics of advertising argue that firms advertise in order to manipulate people’s tastes. 他们还认为，广告抑制了竞争，因为广告努力 使人们相信，产品差别大于实际情况。 They also argue that it impedes competition by implying that products are more different than they truly are. 33 做广告 Advertising 广告的辩护者认为，广告给消费者提供了信息。 Defenders argue that advertising provides information to consumers 他们还认为，广告加剧了竞争，因为它提供了产品和价 格的更多的多样性。 They also argue that advertising increases competition by offering a greater variety of products and prices. 企业花费广告费用的意愿可以是向消费者发出有关它的 产品的质量信号。 The willingness of a firm to spend advertising dollars can be a signal to consumers about the quality of the product being offered. 34 品牌 Brand Names 批评者认为，品牌使消费者感觉到的差 别大于实际存在的差别。 Critics argue that brand names cause consumers to perceive differences that do not really exist. 35 品牌 Brand Names 经济学家认为，品牌是消费者保证他们购买的 物品高质量的一种有用方法。 Economists have argued that brand names may be a useful way for consumers to ensure that the goods they are buying are of high quality. 品牌向消费者提供了质量信息。 providing information about quality. 品牌向企业提供了保持高质量的激励。 giving firms incentive to maintain high quality. 36 总结 Summary 一个垄断竞争市场有三个特征：许多企业，差 别产品和自由进入。 A monopolistically competitive market is characterized by three attributes: many firms, differentiated products, and free entry. 垄断竞争市场的均衡不同于完全竞争之处在于 ，每个企业有超额生产能力和收取高于边际成 本的价格。 The equilibrium in a monopolistically competitive market differs from perfect competition in that each firm has excess capacity and each firm charges a price above marginal cost
总结 总结 Summary Summary ◆垄断竞争不同时具备完全竞争的所有合意特 垄断竞争市场所固有的产品差别导致了广 性 Monopolistic competition does not hay 告与品牌的使用 all of the desirable properties of perfect The product differentiation inherent in monopolistic competition leads to the use 灌德边断虎请流美的价格加成,它有一个 of advertising and brand names There is a standard deadweight loss of 丁滑龄浑为字们是为 monopoly caused by the markup of price over marginal cost. Critics of advertising and brand names argu that firms use them to take advantage of ◆企业的数目可能太多或太少。 consumer irrationality and to reduce The number of firms can be too large or too competition. 总结 Summary ◆辨护者认为,企业使用广告和品牌是为 了向消费者提供信息,并在价格和产品 质量上进行更激烈地竞争 Defenders argue that firms use advertising and brand names to in form consumers and to compete more vigorously on price and product quality
7 37 总结 Summary 垄断竞争不同时具备完全竞争的所有合意特 性。Monopolistic competition does not have all of the desirable properties of perfect competition. 由于在边际成本之上的价格加成，它有一个 标准的垄断无谓损失。 There is a standard deadweight loss of monopoly caused by the markup of price over marginal cost. 企业的数目可能太多或太少。 The number of firms can be too large or too small. 38 总结 Summary 垄断竞争市场所固有的产品差别导致了广 告与品牌的使用。 The product differentiation inherent in monopolistic competition leads to the use of advertising and brand names. 广告与品牌的批评者认为，企业使用它们是为 了利用消费者的非理性，以及减少竞争。 Critics of advertising and brand names argue that firms use them to take advantage of consumer irrationality and to reduce competition. 39 总结 Summary 辩护者认为，企业使用广告和品牌是为 了向消费者提供信息，并在价格和产品 质量上进行更激烈地竞争。 Defenders argue that firms use advertising and brand names to inform consumers and to compete more vigorously on price and product quality