寡头垄断市场上的价格和产量的决定

1、7.5 decision of price and output under oligopoly market寡头垄断市场上的价格和产量的决定1. definition and features of oligopolyoligopoly describes a market structure where just a few firms between them control a large proportion of the industry. it is probably the most dominant market structure in the uk today. most

2、 oligopolists produce differentiated products and much of the competition between them is in the marketing of their particular brands. the greater the product differentiation, the greater the scope to be a price-maker rather than a price-taker.as there are relatively few large firms in the market th

3、ey must be constantly aware of the strategies of their competitors. this means that they are mutually dependent. one of the key features of oligopoly, therefore, is interdependence. each firm will be affected by its rivals decisions. in the same way its actions will also affect its rivals. firms are

4、 acutely aware of this mutual dependence and it will have a great influence on their decisions. for instance, how will competitors react to a price reduction, a new advertising campaign or the development of a new product? the substance of oligopolistic competition is that each firms price and outpu

5、t decision is influenced by perceptions of rivals countermoves.given the large number of permutations that are possible, based on different reactions, no one model of oligopoly exists as for firms in perfect competition, pure monopoly and monopolistic competition. however, several theories have been

6、 developed based on different assumptions about competitors behaviour, the extent and form of entry and exit barriers, and the likelihood of collusion between suppliers.despite the differences between firms in oligopolistic markets, there are therefore two key features that distinguish oligopoly fro

7、m other market structures:1. barriers to entry. the size of the barrier will differ from industry to industry. in some cases entry is relatively easy, while in others it is very difficult.2. interdependence of the firms.寡头垄断是指这样一种市场结构，在这里，几家大厂商生产和销售了整个行业的极大部分产品，其中每个厂商在该行业中都有举足轻重的地位。这与完全垄断和垄断竞争市场不同。完

8、全垄断市场只有一家厂商， 这家厂商的供给就是一个行业的供给。垄断竞争市场则有较多的厂商，每家厂商只是行业中的一小份子。由于寡头市场只有几家厂商，所以，每家厂商的产量和价格的变动都会严重地影响到本行业竞争对手的销售量和销售收入。这样，每家厂商必然会对其他厂商的产量和价格变动做出直接反应，他在做出决策时必须考虑其他厂商的决策，同时，他也要考虑自己的决策对别的厂商的影响。因此，寡头市场是一个相互依存的市场结构。寡头市场在价格与产量决策上有以下三方面特点：一是它很难对产量与价格问题做出像前三种市场类型那样确切而肯定的答案。因为，各个寡头在做出自己的价格和产量决策时，都要考虑到竞争对手的反应，而竞争对手

9、的反应又是多种多样并难以捉摸的。二是价格和产量一旦确定以后，就有其相对稳定性。这也就是说，各个寡头由于难以捉摸对手的行为，一般不会轻易变动已确定的价格与产量水平。三是各寡头之间的相互依存性，使他们之间更容易形成某种形式的勾结。但各寡头之间的利益又是矛盾的，这就决定了勾结不能代替或取消竞争，寡头之间的竞争往往会更加激烈。这种竞争有价格竞争，也有非价格竞争。2. competition and collusionoligopolists are pulled in two different directions:1. the mutually dependence of firms may te

10、mpt them to join together. if they collude in this manner they could jointly maximize industry profits.2. on the other hand there is a great temptation for an individual firm to compete with its rivals to gain market share.these two polices are incompatible. the more fiercely firms compete to gain a

11、 bigger share of industry profits, the smaller these industry profits will become. this is because price competition will drive down the average industry price, while an intensive marketing campaign will increase costs.各寡头之间有可能存在相互之间的勾结，也有可能不存在勾结。在这两种情况下，产量的决定方式是有差别的。当各寡头之间存在勾结时，产量由各寡头之间协商确定，而协商确定的结

12、果有利于谁，则取决于实力的大小。这种协商可能是对产量的限定，也可能是对销售市场的瓜分，即不规定具体产量的限制，而是规定各寡头的具体范围。当然，这种勾结往往是暂时的，当各寡头的实力发生变化之后，就会要求重新确定产量或瓜分市场，从而引起激烈的竞争。在不存在勾结的情况下，各寡头根据其他寡头的产量决策来调整自己的产量，以达到利润最大化，对这一点要根据不同的假设条件进行分析。经济学家曾作了许多不同的假设，并得出了不同的答案。其中一个著名的分析结论就是流传最广的关于“囚徒困境”的推论。这个故事是说：有a和b两个嫌疑犯纵火之后逃跑，被警察抓住了，因证据不足而很难定罪。办案的法官分别找他们谈话，单独对他们其中

13、的每一个人说，如果你招了，他不招，那么你会作为证人无罪释放，他将被判十五年徒刑；如果你招了，他也招了，你们都将被判十年徒刑；如果他招了，你不招，他无罪释放，你十五年；如果你们都不招，各判一年。往往结果两个人都招供了，各被判十年。为什么两个人都选择了“招供”呢？其“思想搏斗过程”大致如下：假如他招了，我不招，我就要坐十五年监狱，招了最坏坐十年，还是招了合算；假如他不招，我也不招，只坐一年（因无法串供，风险太大）；如果我招，他不招，马上被释放，也是招了合算。综合上述情况考虑，还是招了合算，于是两个人都招供了。这个故事说明，在一个集体里，有可能每个人的选择都是理性的，但对于整个集体来说其结果却不是理

14、性的。寡头垄断市场上的经营决策是少数几个人之间的博弈过程，在这个“博弈场”中，参与赌博的人虽然事先规定了行为规则，但每个赌徒都想使自己在其中处于有利的地位，就像a和b两人一样。大家都想将别人陷于“倒霉”的境地，而使自己从困境中逃脱出来，大家都这样做的结果，使大家都享受了风险共担的结果。通过上例推论可以看出，在寡头垄断市场上，寡头之间的勾结可能成功，也可能不成功，相互勾结和相互竞争对市场价格的影响各不相同。people often think and behave strategically how you thinks others will respond to your actions i

15、s likely to influence your own behaviour. firms, for example, when considering a price or product change will often take into account the likely reactions of their rivals.2. 1 collusive oligopolycollusive oligopoly occurs where firms agree, either formally or informally, to limit the competition bet

16、ween them. they may agree on prices, market share, advertising expenditure etc. such collusion will reduce the uncertainty the firms face in a fiercely competitive environment. it will reduce the fear of engaging in competitive price-cutting or other strategies, which could reduce total industry pro

17、fit.a formal collusive agreement is known as a cartel. however, cartels are effectively prohibited in britain under the restrictive trade practices legislation. where open collusion is illegal, firms may try to get round the law by tacit collusion. in such circumstances firms may agree to avoid pric

18、e wars by all the suppliers keeping their prices in line with one another or avoiding aggressive advertising campaigns.in this section we shall examine the economics of firms who have entered into a cartel. an advantage of a cartel is that it can maximize profits as all the firms within it behave as

19、 if they were a single firm. this is shown in figure 1. pprofit-maximising cartelthe total market demand curve is shown with the corresponding market mr curve. the cartels mc curve is the horizontal sum of the mc curves of its members. this is because we are adding the output of each of the cartel m

20、embers at each level of marginal cost. profits are maximized at q where mc=mr. the cartel will therefore set a price of p at which q will be demanded.qquantity0industry mrindustry d=arindustry mcpricefigure 1. profit-maximizing cartel 2.2 how does the cartel divide up the market?from figure 1 it can

21、 be seen that the cartel will maximise profits if each firm charges a price of p. however, at a price of p an output of q will be demanded. the firms within the cartel must decide on how to divide q output amongst themselves. having decided on the price, one way of dividing the market would be by us

22、ing non-price competition for each firm to gain as big a share of the resulting sales as they can.another method would be for each of the cartel members to agree on dividing the market up between them in a particular way so that each member is given a quota. the sum of all the quotas must add up to

23、q. if quotas exceeded q, prices would fall. there is, of course, a great temptation to cheat on the agreement and sell more than your allocated quota. as stated above, if cheating does happen, then it will eventually become obvious, as some firms are unable to sell all their stock at price p, or pri

24、ces will begin to fall.another method, which is probably the fairest as far as the members are concerned, is to divide the market according to current market shares.2. 3 tacit collusionas formal collusive agreements such as cartels are effectively prohibited under british law, firms may enter into t

25、acit agreements instead. in such cases firms will follow unwritten rules where they take care not to engage in price cutting, excessive form of advertising etc.2.3.1 price leadershipin some oligopolistic markets uncertainty in the market is reduced because one supplier may decide to take the initiat

26、ive and act as a price leader. there are various possible types of price leadership in oligopolistic markets dominant firm price leadership. this exists when there is one large firm in the market and a number of smaller competitors. the dominant firm sets its own price, which the other firms then us

27、e as a guide for their prices. this works best where costs of production are similar, thus reducing the risk of any firm attempting to undercut the others prices in a major way. barometric price leadership. in some markets one barometer firm, which does not have to be the dominant firm, best assesse

28、s changes in demand and cost conditions and alters its price. the other firms then follow providing this is in their interests. the barometer may well change over time.1. dominant firm price leadershipd leaderpp1figure 2(a) shows the total demand curve. the supply curve for all the followers is also

29、 shown. these firms accept the price set by the leader and their joint supply curve is simply the sum of their mc curves.the leaders demand curve can be seen as that portion of market demand unfilled by the other firms. at p the whole of market demand is satisfied by the other firms, and so the dema

30、nd for the leader is zero (point a). at p1 the other firms supply is zero, and so the leader faces the full market demand (point b). the leaders demand curve thus connects points a and b.(a) division of market between leader and followers 0quantityprice s all other firmsd marketfigure 2. 0 ql qf qt

31、quantitymc leaderd marketdleaderthe leaders profit will be maximised where its marginal cost equals its marginal revenue.this is shown in figure 2 (b) opposite. the leaders marginal cost equals its marginal revenue at an output of ql, giving a point l on its demand curve. the leader then sets a pric

32、e of pl, which the others then follow. they supply qf, at a point f on their supply curve. total market demand at pl is qt, which is point t on the market demand curve. total output qt must add up to the output of both leaders and followers, ql and qf.mc leader s all other firmspricepl(b) determinat

33、ion of price and output 2. barometric firm price leadershipa similar model could be constructed for a barometric firm. although the firm is not dominating the industry, the others will follow its price. in practice, which firm is taken as the barometer will frequently change. whether we are talking

34、about food retailers, oil companies, car producers or banks, any firm may take the initiative in raising prices. if the other firms are merely waiting for someone to take the lead, say because costs have risen, they will quickly follow suit.寡头垄断市场上的价格的决定也要区分存在或不存在勾结。在不存在勾结的情况下，价格决定的方法是价格领先制；在存在勾结的情况

35、下，则是卡特尔。价格领先制是指一个行业的价格通常由某一寡头率先制定，其余寡头追随其后确定各自价格。领先订价者往往既不是自封的，也不是共同推选的，而是自然形成的。这种自然形成的领先订价者或者可以看作是价格领袖，一般有三种情况：第一，支配型价格领袖。领先确定价格的厂商是本行业中实力最大的、具有支配地位的厂商。它在市场上占有额份最大，因此对价格的决定举足轻重。它根据自己利润最大化的原则确定产品价格及其变动，其余规模较小的寡头则根据这种价格来确定自己的价格以及产量。第二，效率型价格领袖。在这种情况下领先确定价格的厂商是本行业中成本最低，效率最高的厂商。它对价格的确定也使其他厂商不得不随之变动。第三，晴

36、雨表型价格领袖。这种厂商并不一定在本行业中规模最大，也不一定效率最高，但它在掌握市场行情变化或其他信息方面明显优于其他厂商。这家厂商价格的变动实际上是首先传递了某种信息，因此，它的价格在该行业中具有晴雨表的作用，其他厂商会参照这家厂商的价格变动而变动自己的价格。卡特尔（cartel）是生产同类产品的厂商，在划分销售市场、规定商品产量、确定商品价格等方面签订协定而成立的同盟。通过建立卡特尔，几家寡头企业，协调行动，共同确定价格，就有可能像垄断企业一样，使整个行业的利润达到最大。但由于卡特尔各成员之间的矛盾，有时达成的协议也很难兑现，或引起卡特尔解体。在不存在公开勾结的卡特尔的情况下，各寡头还能通

37、过暗中的串通来确定价格。寡头垄断厂商的定价方法通常是成本加成法。就是在核定成本的基础上，加上一个百分比或预期利润额来确定价格。这是按利润最大化原则事先确定利润目标的定价，它能为市场所接受，是因为垄断组织控制着生产和市场销售的最大份额。2.3.2tacit collusion rules of thumban alternative to price leadership is for members to follow a simple set of rules of thumb. these rules do not involve setting mc equal to mr, and s

38、o profits may initially decrease. however, as these rules are deliberately set up to avoid an outbreak of competition, they help to maintain profits in the long run.(a) average cost pricingin this case all producers simply add a certain percentage for profit on top of average costs. thus, if average

39、 costs rise by 5 per cent, prices will automatically rise by 5 per cent. this is particularly useful in times of inflation when suppliers are experiencing similar cost increases.(b) price benchmarksin these firms products are priced for 5.99, 10.99 or 15.99. if costs rise, then firms simply raise th

40、eir price to the next benchmark, knowing that other firms will follow suit. factors favouring collusionthere are only a few firms and hence they are well known to each other.there is a dominant firm.they are not secretive with each other about costs and production methods.there are significant barri

41、ers to entry and thus there is little fear of disruption by new firms.they have similar production methods and average costs, and will thus be likely to want to change prices at the same time and by the same percentage.the market is stable. if industry demand or production costs fluctuate wildly, it

42、 will be difficult to make agreements, due to the uncertainty involved in making such predictions.they produce similar products and can thus more easily reach agreements on price.there are no government measures to control collusion 3. non-collusive oligopoly3.1 why does collusion breakdown?in some

43、cases there may only be a few factors favouring collusion. even if there is collusion, there is always the temptation to cheat, by cutting prices or by selling more than the allocated quota.quota (set by a cartel) the output that a given member of a cartel is allowed to produce (production quota) or

44、 sell (sales quota).figure 3: the incentive for a firm to cheat within collusive oligopolymcthe figure opposite assumes a cartel consisting of five equal-sized firms. the cartel sets the industry profit-maximising price of 10. this will give an industry output of 1000 units. the cartel divides this

45、output equally between its five members: i.e. each member has a quota of 200 units.1210864201000 2000 3000 quantitymr arprice(a) the industrymcc cart cartel price (=mr if price remains fixed pricediagram 3 (b) opposite shows the position for one of the members of the cartel, firm a. if the cartels price remains fixed at 10, then 10 is also the mr for the indivi