产业经济.doc

Market 一。Perfect competition N-正无穷 二imperfect competition 1.monopolistic competition 2.oligopoly N2 3.duopoly N=2 4.monopoly N=1. Market power: is defined as the ability to set prices above cost, specifically above incremental or marginal cost.S-C-P paradigm结构-行为-绩效分析模型Structure: characteristics of the market.number of firms, distribution of market share, degree of product differentiation, entry conditions,Conduct: choices of firms.price, quantity, investments, service, quality. Performance: how firms do.price, consumer surplus, product variety, technological progress.Separation of ownership from management divergent objectives between owners and managers the managers may not act for the interests of the shareholdersPrincipals (shareholders)变成了Agents (managers)Do firms (management) maximize profits?Although management and ownership are normally separated, there are reasons to believe that deviations from profit maximization cannot be too large. These reasons include: Management incentive contracts; Labor market discipline; Product market discipline; Capital market discipline.Specific assets: Once those investments are made, the resulting assets can be used only for the specific type for which they were created. A game is a stylized model that depicts situations of strategic behavior, where the payoff for one agent depends on its own actions as well as on the actions of other agents.A game consists of:PlayersRules (Strategies)Payoff functionsPlayers: Player 1 and Player 2Strategies: Player 1 has two possible strategies T and B; Player 2 has two possible strategies L and RPayoff functions: the respective matrix cell shows the payoffs received by each player Dominant strategyWhenever a player has a strategy that is strictly better than any other strategy regardless of the other players strategy choices, we say that the first player has a dominant strategy.If a player has a dominant strategy and if the player is rational The player chooses the dominant strategy Nash equilibriumA pair of strategies constitutes a Nash equilibrium if no player can unilaterally change its strategy in a way that improves its payoff.Monopoly powerThe degree of monopoly power is inversely related to the demand elasticity faced by the firm.perfect competition is based on five assumptions:(1) atomicity: many firms, each firm is small (2) product homogeneity(3) perfect information(4) equal access (technology)(5) free entryPerfect competition implies maximum efficiency in a static sense, that is, for a given set of available technologies.完全竞争意味着在静态意义下，即在给定技术的条件下，效率达到最大化。Monopolistic competitionEquilibrium profits under monopolistic competition are zero, but firms do not produce at the minimum of their average cost.垄断竞争下的均衡利润为零，但企业并不在最低平均成本处生产。Oligopoly （寡占或寡头垄断）The situation in which there are a few competitors is designated by oligopoly (duopoly双寡头垄断if the number is two).Monopoly, Duopoly, and Perfect CompetitionDuopoly output is greater than monopoly output and lower than perfect competition output. Likewise, duopoly price is lower than monopoly price and greater than price under perfect competition.双寡头垄断的产量大于垄断产量，而小于完全竞争的产量。同理，双寡头垄断的价格低于垄断价格而高于完全竞争价格。collusive pricing Collusive pricing is more likely to be an equilibrium the greater the frequency with which firms interact and the greater the probability of continuation and growth of the industry.企业间相互作用越频繁，行业存在和增长的可能性越大，合谋定价就越趋于均衡Collusion is normally easier to maintain among few and similar firms.合谋通常在少数相类似的企业间更容易达成Collusion is normally easier to maintain when firms compete in more than one market.当企业在多于一个市场中竞争时，更易维持合谋。Measuring market powerLerner index （勒纳指数） : defined as the weighted average of each firms margin, with weights given by the firms market shares. where Si is firm is market share.Measuring market concentration衡量市场集中度Herfindahl index 赫芬德尔指数Frequently, the value of H is multiplied by 10,000, so that it varies between zero and 10,000.The degree of market power depends on three factors (1) demand elasticity, (2) market concentration, and (3) collusive behavior市场势力的大小取决于三个因素：（1）需求弹性，（2）市场集中度，（3）合谋行为Price discrimination: The practice of setting different prices for the same good, whereby the relevant price in each case depends on the quantity purchased, on the buyers characteristics, or on various sale clauses.Second-degree (二级): The firm charges a different price, depending on quantity purchased (but not on the identity of the consumer). 2nd degree price discriminationTwo-part tariff （两部收费制） : a fixed part f, which each consumer must pay regardless of quantity purchased, and a variable part p, proportional to the quantity purchased.3rd degree price discriminationUnder third-degree price discrimination, a seller should charge a lower price in those market segments with greater price elasticity.Pure bundling: Buyers must purchase the bundle or nothing.Mixed bundling: Buyers are offered the choice between purchasing the bundle or one of the separate parts.Vertical relations-relations between two firms in sequence along the value chain. Normally, we will refer to the case of a manufacturer selling to one or several retailers. Vertical restraints纵向约束: An upstream firm might want to establish contractual terms to restrain the downstream firm in some way.Retailer competitionThe greater the degree of competition between retailers, the higher the optimal wholesale prices.零售商之间的竞争越激烈，最优批发价格就越高Investment externalities投资外部性Resale-price Maintenance (RPM转售价格控制): the manufacturer imposes a minimum price on retailers.Exclusive territories排他性势力范围：each retailer is allocated a given territory that other retailers have no access.When retailers must make investments in sales effort that benefit several retailers, vertical restraints such as RPM and exclusive territories may help by correcting inter-retailer externalities.当零售商在营销上的投资将使其他零售商获益时，纵向约束如转售价格控制和排他性势力范围将有助于修正这种零售商之间的外部性。Vertical restrains such as resale maintenance or exclusive territories may increase efficiency when (1) retailers make investments in sales effort that benefit several retailers or rival manufacturers; or (2) a two-part tariffs is insufficient to simultaneously provide incentives for retail pricing and sales effort.纵向约束如转售价格控制或排他性势力范围可能提高效率，当（1）零售商在营销上的投资将使其他零售商或竞争生产商获益时（2）两部收费制不足以同时激励零售价格的制定和营销努力时。two types of product differentiation产品差异: horizontal differentiation and vertical differentiation.Horizontal differentiation （水平差异） : Goods are different but at the same price some consumers will buy one and some will buy other, it really depends on their preferences. 部分偏好Vertical differentiation（垂直差异） ：Goods are different and all consumers would prefer one to the other if they were sold at the same price. 全部Product differentiation and market powerThe greater the degree of product differentiation, the greater the degree of market power.产品差异的程度越大，市场势力越大Product PositioningIf price competition is intense, then firms tend to locate far apart (high degree of differentiation). If price competition is not intense, then firms tend to locate close to the center (low degree of differentiation).如果价格竞争激烈，那么企业倾向于远离对方（差异化程度高）。如果价格竞争不激烈，那么企业倾向于向中心靠拢（差异化程度低）。The greater the value of search costs or switching costs, the greater the sellers market power tends to be.搜寻成本或转换成本越高，卖者的市场势力就越大Types of goods:A search good （搜寻品） is one whose features the consumer can ascertain before purchase. (e.g. PC)An experience good （经验品） is one whose features can be ascertained only upon consumption. (e.g. red wine)Classification of advertisingInformative advertising （信息性广告） describes the products existence, its characteristics and selling terms.Persuasive advertising （劝说性广告） is designed to change consumers preferences.The social value of advertising signal product qualityAdvertising expenditures may serve to signal product quality.广告费用可能传递有关产品质量的信息Advertising intensity （广告强度） The advertising-to-revenues ratio (广告费用与销售收入的比a/R): The ratio of advertising expenditures to total sales. Dorfman-Steiner formula:The advertising-to-sales ratio is greater the advertising elasticity of demand and the lower the price elasticity of demand (or the greater the price-cost margin).需求广告弹性越大，需求价格弹性越小（或者价格成本差越大），则广告费用与销售额之比就越大Price competition and advertisingGenerally, advertising product characteristics increases product differentiation and consequently softens competition.一般来说，有关产品特征广告能够增加产品差异化和削弱竞争。Advertising prices increase price competition.价格广告加剧价格竞争Entry costs and market structure Due to increased price competition, the equilibrium number of active firms varies less than proportionally with respect to market size.由于价格竞争加剧，在位企业的均衡数量变化程度小于市场规模的变化程度。Scale economies and concentration 规模经济和集中度Concentration is greater the greater the minimum efficient scale (or the greater the degree of scale economies)最小有效规模越大（或规模经济程度越高），集中度越高Barriers to entry are obstacles that make it difficult to enter a given market. Barriers to entry protect a firm from the arrival of new competitors. If product differentiation is very important, or if competition is very fierce, then free implies insufficient entry from social point of view.如果产品差异非常重要，或竞争非常激烈，则从社会福利的角度看自由进入意味着进入不足If, conversely, product differentiation is unimportant and competition is soft, then the business stealing effect dominates, whereby the free-entry equilibrium entails excessive entry. 如果产品差异不重要且竞争较弱，则会产生经营盗窃效果，那么自由进入均衡意味着进入过剩If entry costs are very high, then the incumbent should set monopoly capacity and ignore the threat of entry. 如果进入成本很高，那么在位企业将制定垄断产量，不理会进入威胁If entry costs are very low, then the incumbent should choose capacity, taking into account the entrants reaction curve. 如果进入成本很低，在位者在选择产量时将考虑进入者的反应曲线Finally, if entry costs are intermediate, then the incumbent should choose capacity large enough to induce the entrant not to enter.如果进入成本居中，那么在位企业会选择足够大的生产能力使进入者不进入Predatory pricingPricing below cost to injure rival firms and thus induce their exit is a practice known as predatory pricing掠夺性定价.Predatory pricing may be a successful strategy when (1) the prey is financially constrained, (2) low prices signal low costs or the predators “toughness,” and (3) capturing a minimum market share early on is crucial for long-term survival. In all these cases, low pricing by the predator induces the prey to exit the market.在下列情况下，掠夺性定价有可能是成功的策略：（1）被掠夺者存在财务约束，（2）制定低价格发出低成本信号或表明掠夺者的“强硬态度”，（3）长期生存必需在开始时获得最低市场份额。在上述所用情况时，掠夺者会制定低价格以逼迫进入者退出市场Horizontal mergers（水平并购）: mergers or acquisitions between two firms within the same industry. Goods are substitutes.A hostile takeover （敌意接管） : a merger in which one company buys another that does not want to be taken over Mergers normally imply an increase in prices and a reduction in costs. 兼并通常意味着价格的升高和成本的降低The value of nonmerging firms may decrease or increase as the result of a merger, depending on the cost efficiencies generated by the merger. 非兼并企业的价值将根据兼并成本效率的不同而可能降低或升高The smaller the size of the merging firms, the more likely the total effect of a merger is positive. 兼并企业的规模越小，兼并的总效应越可能是正面的Total output under Cournot equilibrium is greater than under monopoly but lower than under perfect competition. Moreover, as the number of firms increases, total output increases.Finally, as the number of Cournot competitors goes to infinity, total output converges to the value under perfect competition.Reaction functionFirm 1s best response with respect to Firm 2s choiceBertrand Model: EquilibriumUnder price compet