竞争、垄断和卡特尔 寡头的均衡 Competition, Monopolies, and The Equilibrium for an Oligopoly Cartels 定杰克尔最优(尔 选产量的产量弟获簿利 尽管寡头希望形成卡特尔并赚到垄断利润,但 这往往是不可能的。 3,600 Although oligopolists would like to form cartels 头的均简结果 6050) 3,000 and earn monopoly profits, often that is not 50(40 2,000 反托拉斯法把禁止寡头之间的公开协议作为公 共政策的重点。 titrust laws prohibit explicit agreeme oligopolists as a matter of public policy 寡头的均衡 寡头的均衡 The Equilibrium for an Oligopoly Equilibrium for an Oligopoly 5120 如果寡头企业各自追求自己的利益,可能的结 果是: Possible outcome if oligopoly firm pursue their own self-interests ◆总产量大子垄断产量但小于竟争产量 t is greater than ti oly quantity but less than the competitive industry quantity ◆市场价格低于垄断价格但高于竞争价格 Market prices are lower than monopoly price but 寡头的市场结 greater than competitive price. ◆总利涧小于垄断和洞 Total profits are less than the monopoly prof 寡头数量如何影响市场结果 寡头数量如何影响市场结果 How the Size of an Oligopoly How the Size of an Oligopoly Affects the Market outcome Affects the Market outcome 簧时类每个套要驾速青应量的 ◆卖者数目的增加如何影响这两种效应 How increasing the number of sellers affects In making the marginal decision on increasing/decreasing one unit of its production, each seller weighs two effects ◆随着寡头量增加,价格煮应在减少。 As the oligopoly grows in size, the magnitude of the 多答增点阶拾高于边际成本,在现行价格上 he output effect: Because price is above marginal cost, selling more at the going price raises profits. 子划加到大时,价格教应几乎失,只 会降低价 When the oligopoly grows very large, the price effect disappear altogether, leaving only the outpur effect. price and the profit per unit on all units sold.3 13 竞争、垄断和卡特尔 Competition, Monopolies, and Cartels 尽管寡头希望形成卡特尔并赚到垄断利润，但 这往往是不可能的。 Although oligopolists would like to form cartels and earn monopoly profits, often that is not possible. 反托拉斯法把禁止寡头之间的公开协议作为公 共政策的重点。 Antitrust laws prohibit explicit agreements among oligopolists as a matter of public policy. 14 寡头的均衡 The Equilibrium for an Oligopoly 60 30 900 50 40(30) 1,200 40 40 1,600 30 50(40) 2,000 20 50 2,500 10 60(50) 3,000 0 60 3,600 （吉尔） 并获得利 润…… 吉尔最优 的产量选 择是…… 给定杰克 选择产量 为…… Quantity Price Total Revenue 0 $120 $ 0 10 110 1,100 20 100 2,000 30 90 2,700 40 80 3,200 50 70 3,500 60 60 3,600 70 50 3,500 80 40 3,200 90 30 2,700 100 20 2,000 110 10 1,100 120 0 0 寡头的均衡结果 15 寡头的均衡 The Equilibrium for an Oligopoly Quantity Price Total Revenue 0 $120 $ 0 10 110 1,100 20 100 2,000 30 90 2,700 40 80 3,200 50 70 3,500 60 60 3,600 70 50 3,500 80 40 3,200 90 30 2,700 100 20 2,000 110 10 1,100 竞争的市场结果 120 0 0 寡头的市场结果 垄断的市场结果 16 寡头的均衡 Equilibrium for an Oligopoly ‹ 如果寡头企业各自追求自己的利益，可能的结 果是：Possible outcome if oligopoly firms pursue their own self-interests: ‹ 总产量大于垄断产量但小于竞争产量 Joint output is greater than the monopoly quantity but less than the competitive industry quantity. ‹ 市场价格低于垄断价格但高于竞争价格 Market prices are lower than monopoly price but greater than competitive price. ‹ 总利润小于垄断利润 Total profits are less than the monopoly profit. 17 寡头数量如何影响市场结果 How the Size of an Oligopoly Affects the Market Outcome ‹ （与垄断时类似）在做出增加或者减少产量的 边际决策时，每个卖者都要考虑两种效应： In making the marginal decision on increasing/decreasing one unit of its production, each seller weighs two effects: ‹ 产量效应：由于价格高于边际成本，在现行价格上 多销售将增加利润。 The output effect: Because price is above marginal cost, selling more at the going price raises profits. ‹ 价格效应：提高生产将增加总销售量，这会降低价 格并减少所有销售量每一单位的利润。 The price effect: Raising production lowers the price and the profit per unit on all units sold. 18 寡头数量如何影响市场结果 How the Size of an Oligopoly Affects the Market Outcome ‹ 卖者数目的增加如何影响这两种效应 How increasing the number of sellers affects these two effects: ‹ 随着寡头数量增加，价格效应在减少。 As the oligopoly grows in size, the magnitude of the price effect falls. ‹ 当寡头数量增加到极大时，价格效应几乎消失，只 剩下了产量效应。 When the oligopoly grows very large, the price effect disappear altogether, leaving only the output effect