6规模经济、不完全竞争和国际贸易.ppt

1、1,YOU ARE WELCOME !,2,International Economics,国际经济学 主讲：余道先 ,3,Chapter 6,Economies of Scale，Imperfect Competition, and International Trade 规模经济、不完全竞争和国际贸易,4,Introduction Economies of Scale and International Trade: An Overview Economies of Scale and Market Structure The Theory of Imperfect Competition

2、 Monopolistic Competition and Trade Dumping The Theory of External Economies External Economies and International Trade Summary,Preview,5,Introduction,Countries engage in international trade for two basic reasons: Countries trade because they differ either in their resources or in technology. Countr

3、ies trade in order to achieve scale economies or increasing returns in production.,6,Introduction （cont.）,The Ricardian and Heckscher-Ohlin models also rely on competition to predict that all income from production is paid to owners of factors of production: no “excess” or monopoly profits exist. Bu

4、t when economies of scale exist, large firms may be more efficient than small firms, and the industry may consist of a monopoly or a few large firms. Production may be imperfectly competitive in the sense that excess or monopoly profits are captured by large firms.,7,Introduction （cont.）,Two models

5、of international trade in which economies of scale and imperfect competition play a crucial role: Monopolistic competition model（垄断竞争模型） Dumping model（倾销模型）,8,Economies of Scale and International Trade: An Overview,Models of trade based on comparative advantage (e.g. Ricardian model) used the assump

6、tions of constant returns to scale and perfect competition: Increasing the amount of all inputs used in the production of any commodity will increase output of that commodity in the same proportion（增加生产某商品所需的所有要素的投入会使该产品的产量同比例增加）.,9,Economies of Scale and International Trade: An Overview,In practice

7、, many industries are characterized by economies of scale (also referred to as increasing returns). Production is most efficient, the larger the scale at which it takes place（规模越大，生产效率越高）.,10,Under increasing returns to scale: Output grows proportionately more than the increase in all inputs（产出的增长比例

8、比要素投入增加的比例高）. Average costs (costs per unit) decline with the size of the market（随着市场规模的扩张，平均成本（单位成本）降低）.,Economies of Scale and International Trade: An Overview,11,Economies of Scale and International Trade: An Overview,Table 6-1: Relationship of Input to Output for a Hypothetical Industry,12,Econo

9、mies of Scale and Market Structure,Economies of scale can be either: External The cost per unit depends on the size of the industry but not necessarily on the size of any one firm.（单位成本取决于产业规模，而并不一定由单一厂商的规模决定） An industry will typically consist of many small firms and be perfectly competitive.（一个产业是

10、由许多小厂商组成的，而且是完全竞争的）,13,Economies of Scale and Market Structure,Internal The cost per unit depends on the size of an individual firm but not necessarily on that of the industry.（单位成本是由单个厂商的 规模决定的 ，而并不一定是由其所在产业的规模决定的） The market structure will be imperfectly competitive with large firms having a cost

11、advantage over small. Both types of scale economies are important causes of international trade.（上述两种规模经济都是引起国际贸易的重要原因）,14,Imperfect competition Firms are aware that they can influence the price of their product. They know that they can sell more only by reducing their price. Each firm views itself

12、as a price setter, choosing the price of its product, rather than a price taker. The simplest imperfectly competitive market structure is that of a pure monopoly, a market in which a firm faces no competition.,The Theory of Imperfect Competition,15,Monopoly: A Brief Review Marginal revenue The extra

13、 revenue the firm gains from selling an additional unit Its curve, MR, always lies below the demand curve, D. In order to sell an additional unit of output the firm must lower the price of all units sold (not just the marginal one). （为了多销售一单位产出，厂商必须降低所有(而不是最后一单位)出售产品的价格）,The Theory of Imperfect Comp

14、etition,16,The Theory of Imperfect Competition,Figure 6-1: Monopolistic Pricing and Production Decisions,MR,MC,17,Marginal Revenue and Price Marginal revenue is always less than the price. Assume that the demand curve the firm faces is a straight line: Q = A B x P (6-1) Then the MR that the firm fac

15、es is given by: MR = P Q/B (6-2),The Theory of Imperfect Competition,18,The Theory of Imperfect Competition,Average and Marginal Costs Average Cost (AC) is total cost divided by output. Marginal Cost (MC) is the amount it costs the firm to produce one extra unit. When average costs decline in output

16、, marginal cost is always less than average cost.,19,Suppose the costs of a firm, C, take the form: C = F + c x Q (6-3) This is a linear cost function. The fixed cost in a linear cost function gives rise to economies of scale, because the larger the firms output, the less is fixed cost per unit. The

17、 firms average costs is given by: AC = C/Q = F/Q + c (6-4),The Theory of Imperfect Competition,20,Figure 6-2: Average Versus Marginal Cost,The Theory of Imperfect Competition,21,Monopolistic Competition（垄断竞争） Monopolistic competition is a model of an imperfectly competitive industry which assumes th

18、at： Each firm is assumed to be able to differentiate its product from its rivals.（每个厂商均能生产与竞争对手有差异的产品） Each firm is assumed to take the prices charged by its rivals as given.（每个厂商把竞争对手的价格作为既定价格）,The Theory of Imperfect Competition,22,Are there any monopolistically competitive industries in the real

19、world?（在现实中，是否存在垄断竞争行业？） Some industries may be reasonable approximations (e.g., the automobile industry in Europe) The main appeal of the monopolistic competition model is not its realism, but its simplicity.,The Theory of Imperfect Competition,23,Assumptions of the Model Imagine an industry consis

20、ting of a number of firms producing differentiated products（差异产品）. We expect a firm: To sell more the larger the total demand for its industrys product and the higher the prices charged by its rivals（对其所在产业产品的需求越大，其竞争对手制定的价格越高，该厂商销售的产品就越多） To sell less the greater the number of firms in the industry

21、 and the higher its own price（其所在产业拥有的厂商越多，该厂商自身定价越高，销售的产品就越少）,The Theory of Imperfect Competition,24,where: Q is the firms sales S is the total sales of the industry n is the number of firms in the industry b is a constant term representing the responsiveness of a firms sales to its price P is the

22、price charged by the firm itself,The Theory of Imperfect Competition,25,Market Equilibrium All firms in this industry are symmetric The demand function and cost function are identical for all firms. The method for determining the number of firms and the average price charged involves three steps: We

23、 derive a relationship between the number of firms and the average cost of a typical firm. We derive a relationship between the number of firms and the price each firm charges. We derive the equilibrium number of firms and the average price that firms charge.,The Theory of Imperfect Competition,26,1

24、、The number of firms and average cost How do the average costs depend on the number of firms in the industry?,The Theory of Imperfect Competition,We conclude that average cost depends on the size of the market and the number of firms in the industry: AC = F/Q + c = n x F/S + c (6-6) The more firms t

25、here are in the industry the higher is the average cost.,27,2、The number of firms and the price The price the typical firm charges depends on the number of firms in the industry. The more firms, the more competition, and hence the lower the price. In the monopolistic competition model firms are assu

26、med to take each others prices as given.,The Theory of Imperfect Competition,28,Profit-maximizing firms set marginal revenue equal to their marginal cost, c. This generates a negative relationship between the price and the number of firms in the market which is the PP curve: P = c + 1/(b x n) (6-10)

27、 The more firms there are in the industry, the lower the price each firm will charge.,The Theory of Imperfect Competition,29,3、The equilibrium number of firms The downward-sloping curve PP shows that the more firms, the lower the price each firm will charge. The more firms, the more competition each

28、 firm faces. The upward-sloping curve CC tells us that the more firms there are, the higher the average cost of each firm. If the number of firms increases, each firm will sell less, so firms will not be able to move as far down their average cost curve.,The Theory of Imperfect Competition,30,Figure

29、 6-3: Equilibrium in a Monopolistically Competitive Market,The Theory of Imperfect Competition,P2,31,Limitations of the Monopolistic Competition Model Two kinds of behavior arise in the general oligopoly setting that are excluded by assumption from the monopolistic competition model: Collusive behav

30、ior（勾结行为）: Can raise the profits of all firms at the expense of consumers May be managed through explicit agreements（公开协议） or through tacit coordination strategies（心照不宣的合作） Strategic behavior（战略行为）: Is adopted by firms to affect the behavior of competitors in a desirable way（引导其竞争对手向着该厂商希望的方向行动） Det

31、ers potential rivals from entering an industry（阻止潜在竞争者进入该行业）,The Theory of Imperfect Competition,32,The monopolistic competition model can be used to show how trade leads to: A lower average price due to scale economies The availability of a greater variety of goods due to product differentiation Im

32、ports and exports within each industry （intra-industry trade）（产业内贸易）,Monopolistic Competition and Trade,33,The Effects of Increased Market Size The number of firms in a monopolistically competitive industry and the prices they charge are affected by the size of the market. （垄断竞争行业的厂商数量和价格受市场规模的影响）,M

33、onopolistic Competition and Trade,34,The Effects of Increased Market Size Because trade increases market size, trade is predicted to decrease average cost in an industry described by monopolistic competition. Industry sales increase with trade leading to decreased average costs: AC = F(n/S) + c Beca

34、use trade increases the variety of goods that consumers can buy under monopolistic competition, it increases the welfare of consumers. And because average costs decrease, consumers can also benefit from a decreased price.,Monopolistic Competition and Trade,35,Figure 6-4: Effects of a Larger Market,C

35、C2,Monopolistic Competition and Trade,36,Gains from an Integrated Market: A Numerical Example International trade allows creation of an integrated market that is larger than each countrys market（国际贸易可以创造出更大的市场）. It thus becomes possible to offer consumers a greater variety of products and lower pric

36、es（使消费者以更低的价格获得更多的商品）.,Monopolistic Competition and Trade,37,Example: Suppose that automobiles are produced by a monopolistically competitive industry. Assume the following: b = 1/30,000 F = $750,000,000 c = $5000 There are two countries (Home and Foreign) that have the same costs of automobile prod

37、uction（相同的生产成本）. Annual sales of automobiles are 900,000 at Home and 1.6 million at Foreign.,Monopolistic Competition and Trade,38,Figure 6-5: Equilibrium in the Automobile Market,Monopolistic Competition and Trade,39,Figure 6-5: Continued,Monopolistic Competition and Trade,40,Figure 6-5: Continued,

38、Monopolistic Competition and Trade,41,Table 6-2: Hypothetical Example of Gains from Market Integration,Monopolistic Competition and Trade,42,Economies of Scale and Comparative Advantage（规模经济和比较优势） Assumptions: There are two countries: Home (the capital-abundant country) and Foreign. There are two in

39、dustries: manufactures (the capital-intensive industry) and food. Neither country is able to produce the full range of manufactured products by itself due to economies of scale（由于规模经济的存在，两个国家都不会自己生产全部的制成品）.,Monopolistic Competition and Trade,43,Figure 6-6: Trade in a World Without Increasing Returns

40、 （不存在收益递增时的贸易）,Monopolistic Competition and Trade,44,If manufactures is a monopolistically competitive sector, world trade consists of two parts（如果制造业是垄断竞争的部门，国际贸易由以下两部分组成）: Intraindustry trade（产业内贸易） The exchange of manufactures for manufactures Interindustry trade（产业间贸易） The exchange of manufactur

41、es for food,Monopolistic Competition and Trade,45,Figure 6-7: Trade with Increasing Returns and Monopolistic Competition （收益递增和垄断竞争下的贸易）,Food,Monopolistic Competition and Trade,46,Main differences between inter-industry and intra-industry trade: Inter-industry trade reflects comparative advantage, w

42、hereas intra-industry trade does not（产业间贸易反映了比较优势，而产业内贸易没有）. The pattern of intra-industry trade itself is unpredictable, whereas that of inter-industry trade is determined by underlying differences between countries（产业内贸易模式本身是不可预见的，而产业间贸易的模式是由国家间内在的差异性决定的）.,Monopolistic Competition and Trade,47,Mai

43、n differences between inter-industry and intra-industry trade（cont.）: The relative importance of intra-industry and inter-industry trade depends on how similar countries are（产业内贸易和产业间贸易的相对重要性是由国家间的相似程度决定的）. Countries with similar relative amounts of factors of production are predicted to have intra-

44、industry trade. Countries with different relative amounts of factors of production are predicted to have inter-industry trade. Unlike inter-industry trade in the Heckscher-Ohlin model, income distribution effects are not predicted to occur with intra-industry trade.,Monopolistic Competition and Trad

45、e,48,The Significance of Intra-industry Trade About one-fourth of world trade consists of intra-industry trade. Intra-industry trade plays a particularly large role in the trade in manufactured goods among advanced industrial nations, which accounts for most of world trade.,Monopolistic Competition

46、and Trade,49,Table 6-3: Indexes of Intraindustry Trade for U.S. Industries, 1993,Monopolistic Competition and Trade,50,Why Intra-industry Trade Matters Intra-industry trade allows countries to benefit from larger markets（产业内贸易使国家可以从更大的市场规模中获利）. The case study of the North American Auto Pact（北美汽车贸易协定

47、） of 1964 indicates that the gains from creating an integrated industry in two countries can be substantial.,Monopolistic Competition and Trade,51,Gains from intra-industry trade will be large when economies of scale are strong and products are highly differentiated（规模经济和产品差异非常重要以至于从规模经济和增加商品选择中得到的收

48、益非常大）. For example, sophisticated manufactured goods（工艺复杂的制成品）.,Monopolistic Competition and Trade,52,The Economics of Dumping Price discrimination（价格歧视） The practice of charging different customers different prices Dumping（倾销） The most common form of price discrimination in international trade A pr

49、icing practice in which a firm charges a lower price for an exported good than it does for the same good sold domestically（是指这样一种定价行为，一个厂商对出口产品制定的价格要低于国内同类产品的价格）,Dumping,53,It is a controversial issue in trade policy and is widely regarded as an unfair practice in international trade. Example: As of

50、 April 2002, the United States had anti-dumping duties on 265 items from 40 different countries. Dumping can occur only if two conditions are met: （倾销的成立须满足两个条件） Imperfectly competitive industry（不完全竞争的产业） Segmented markets（分割的市场） Given these conditions, a monopolistic firm may find that it is profit

51、able to engage in dumping.,Dumping,54,Dumping,Dumping may be a profit maximizing strategy because of differences in foreign and domestic markets. One difference is that domestic firms usually have a larger share of the domestic market than they do of foreign markets. Because of less market dominance

52、 and more competition in foreign markets, foreign sales are usually more responsive to price changes than domestic sales. Domestic firms may be able to charge a high price in the domestic market but must charge a low price on exports if foreign consumers are more responsive to price changes.,55,Dump

53、ing,We draw a diagram of how dumping occurs when a firm is a monopolist in the domestic market but must compete in foreign markets. Because the firm is a monopolist in the domestic market, the demand function that it faces in the domestic market is downward sloping, and marginal revenue from additio

54、nal output is always less than a uniform price for all units of output. Because the firm competes in foreign markets, the demand function that it faces in foreign markets is horizontal, representing the fact that exports are very responsive to small price changes.,56,Dumping,To maximize profits, the

55、 firm should sell a limited amount in the domestic market at a high price PDOM , but sell in foreign markets at a low price PFOR. Since more can always be sold at PFOR , the firm should sell its products at a high price in the domestic market until marginal revenue there falls to PFOR. Thereafter, i

56、t should sell exports at PFOR until marginal costs exceed this price. In this case, dumping is a profit-maximizing strategy.,57,Figure 6-8: Dumping,Dumping,Exports,Domestic sales,DFOR = MRFOR,PFOR,58,Reciprocal Dumping（相互倾销） A situation in which dumping leads to two-way trade in the same product（倾销导

57、致同种产品的双向贸易） It increases the volume of trade in goods that are not quite identical（增加了不完全相同商品的贸易量）. Its net welfare effect is ambiguous: It wastes resources in transportation. It creates some competition.,Dumping,59,Reciprocal Dumping,Dumping (as well as price discrimination in domestic markets) is

58、widely regarded as unfair. A US firm may appeal to the Commerce Department to investigate if dumping by foreign firms has injured the US firm. The Commerce Department may impose an “anti-dumping duty,” or tax, as a precaution（预防措施） against possible injury. This tax equals the difference between the

59、actual and “fair” price of imports, where “fair” means “price the product is normally sold at in the manufacturers domestic market.”,60,Reciprocal Dumping,Next the International Trade Commission (ITC) determines if injury to the U.S. firm has occurred or is likely to occur. If the ITC determines that injury has occurred or is likely to occur, the anti-dumping duty remains in place. See /trade_remedy/731_ad_701_cvd/index.htm,61,The Theory of External Economies,Economies of scale that occur at the level of the