產業(yè)組織理論課件：Lecture 9 Price discrimination

1、產業(yè)組織理論Theory of Industrial Organization Lecture 9 Price discrimination OutlineConcepts of price discriminationTypes of price discriminationTwo-part tariffs, tying and bundlingDistribution effects of price discriminationImpacts of price discrimination on competitionfirst-degree price discrimination 第

2、一級價格歧視second-degree price discrimination第二級價格歧視third-degree price discrimination 第三級價格歧視secondary-line cases第二級案例secondary-line market第二級市場requirements tie-in sales必要搭售mixed bundling混合捆綁銷售tie-in sales搭售two-part tariff雙重收費KEY TERMSbasing point pricing system基點定價機制Bundling捆綁銷售perfect discrimination完全價

3、格歧視predatory discrimination掠奪性歧視price discrimination價格歧視primary-line cases第一級案例primary-line competition第一級競爭relative valuation相對估值Foreclosure排斥KEY TERMSPrice discrimination exists when a firm charges either different consumers different prices for the same product supplied with identical costs or di

4、fferent consumers the same price even though the cost of supplying the good varies between consumers.More generally, price discrimination occurs whenever the difference in prices between consumers is not proportional to the difference in costsi.e., whenever the price-cost margin varies between diffe

5、rent consumers.DefinitionConsider some examples of price discrimination: two airline passengers paying different fares for coach seats on the same flight; a lawyer charging the same fee for a will that requires 30 minutes of preparation time as a will that requires 8 hours of preparation time; or a

6、department store offering a second pair of jeans at a price 50 percent lower than the first pair. However, two passengers paying different fares for coach seats on different days of the year (e.g., Thanksgiving Day and November 1) may not onstitute price discrimination.DefinitionThere are several im

7、portant points to understand about price discrimination. Perhaps the most significant is that discrimination can occur only if market power exists. If two sellers in a perfectly competitive market charge different prices for the same good, consumers will buy only from the lower-priced seller. Also,

8、the existence of most price discrimination implies a lack of Pareto efficiency; because different consumers face different marginal rates of substitution (MRS), efficiency in exchange is not achieved.DefinitionEconomists divide price discrimination into three general categories: first-degree price d

9、iscriminationsecond-degree price discriminationthird-degree price discriminationTypes of Price DiscriminationIn first-degree price discrimination is often referred to perfect discriminationEach consumer pays his or her reservation price for the good, which is the highest price he or she is willing t

10、o pay for the goodTypes of Price DiscriminationWith second-degree price discrimination , a firm offers all consumers the same price schedule, and then consumers self-select into the different price categoriesThird-degree price discrimination depends on the firms ability to effectively separate consu

11、mers into two or more groups according to their elasticities of demandUnlike second-degree price discrimination, in third-degree discrimination, consumers are put into a group by the firm and cannot self-select into another groupTypes of Price DiscriminationFirst-Degree Price DiscriminationEach unit

12、 is sold for the maximum price some consumer is willing to payWith demand P = 10 - Q, the first unit is sold for $9, the second unit for $8, the third for $7, until the eighth unit is sold for $2Total revenue equals $9 + $8 + $7 + $6 + $5 + $4 + $3 + $2 = $44There is no consumer surplus, but produce

13、r surplus equals the sum of the light blue, gray, and dark blue shaded areas X + Y + ZAlthough consumers pay different prices, every consumer who buys within the same price category pays the same priceFirms use second-degree discrimination when they know there are different groups of consumers with

14、different reservation prices, but they are unable to identify, or it is too costly to identify, each type of consumerSecond-Degree Price DiscriminationConsumers purchase one pair of jeans for $80, a second pair for $60, a third pair for $40, and a fourth pair for $20A total of 100 pairs are sold and

15、 total revenue equals the sum of the shaded areas A + B + C + D, or $6000Second-Degree Price DiscriminationConsumer surplus is the sum of the four shaded areas W + X + Y + ZProducer surplus is the sum of the three shaded rectangles A + B + C, which equals $4000.Second-Degree Price DiscriminationThe

16、Demand for Ralph Lauren Jeans Using Second-Degree Price DiscriminationUnlike first-degree discrimination, there is some consumer surplus in the case of second-degree discriminationBecause the seller cannot identify precisely the demand for each and every consumer, he or she is unable to extract the

17、entire consumer surplus from the market壟With third-degree price discrimination, fi rms are able to separate consumers into two or more groups according to their different elasticities of demandConsumers are put into a group by the fi rm and cannot self-select into another groupAs long as the fi rm c

18、an distinguish the groups by their different elasticities at any given price, practicing price discrimination increases profitThird-Degree Price Discrimination壟To maximize profit, the theater equates marginal revenue to marginal cost in each market and charges a price of (a) $5.50 per ticket to adul

19、ts and (b) $3.00 per ticket to seniorsTotal consumer plus producer surplus in both markets is the sum of shaded areas A + B + C + D, which equals $483.75The Demand for Movies for Adults and Senior CitizensThe sum of the adult and senior demand curves for movie tickets is the horizontal summation of

20、the two demand curves For prices above $5.00, this consists of only the adults-under-65 demand p = 10.00 - (110)q. For prices below $5.00, the demand curve is p = 6.25 - (140)qThe complete demand curve is the kinked dark blue curve ABCCombined Demand for Movie TicketsTo maximize profit, the theater

21、equates marginal revenue to marginal cost on the second segment of the MR curve at q = 105 and sets the price at $3.625Producer surplus equals the light blue shaded area C and consumer surplus equals the sum of the dark blue and light gray shaded areas A + BThe sum of consumer and producer surplus e

22、quals $507.1875The Profit-Maximizing Uniform PriceAmong the most common forms of second-degree price discrimination are two-part tariffs, tying, and bundling The three concepts are closely related, they differ only technicallyTwo-Part Tariffs, Tying, and BundlingA two-part tariff consists of a lump

23、sum payment for a good or service combined with a per unit user chargeCommon examples include a rental charge for a copier and a per-copy fee; a golf club that charges a membership fee and a greens fee per round; and an amusement park that charges an entrance fee and a per-attraction charge.Two-Part

24、 TariffsUnder a tie-in sales agreement, consumers can purchase a good only if they agree to purchase another good. Tie-in sales agreements are subdivided into two types: package tie-in sales, typically called bundling, and requirements tie-in sales. Bundling is a tying agreement in which the goods a

25、re purchased in fi xed proportions. The most important recent example is the bundling of Microsofts Windows operating system with Microsofts Internet Explorer browser. Another important example is a restaurant that serves only a fi xed-price menu including an appetizer, salad, entre, and dessertTwo-

26、Part TariffsBundling is a tying arrangement in which the goods are purchased in fixed proportionsOne famous example of bundling occurred in the motion picture industry during the golden years of major studio domination of the industryThe major motion picture producer-distributors, such as MGM, Param

27、ount, and Fox, bundled high-quality and lowquality pictures together and forced theaters to purchase their entire package of filmsBundlingIt is fairly common for firms to give consumers the choice of paying for products separately or bundled together in packages, a practice known as mixed bundlingFo

28、r example, most restaurants, from McDonalds to haute cuisine French restaurants, offer an la carte menu and a bundled fixed price complete meal menu. Similarly, all professional sports teams offer tickets to individual games and season ticket packages of bundled ticketsPresumably, offering consumers

29、 this choice maximizes profi ts of the restaurant or the sports teamMixed Bundlingrequirements tie-in sales consist of a tying agreement in which the goods are purchased in variable proportionsIn a typical requirements tie-in, a firm with market power over good X requires its buyers to purchase all

30、of their requirements of a complementary good, good Y, in order to obtain good XRequirements Tie-in SalesThe distribution effects of price discrimination are straightforwardproducers as a group gain and consumers as a group loseIn fact, the producers incentive to discriminate is a desire to increase

31、 profitsFirst-degree discrimination carries this to an extreme: All of the consumer surplus is transferred to producersDistribution Effects of Price DiscriminationIs this redistribution of income good or bad? The answer depends entirely on value judgmentsPrice discrimination always increases profits

32、, and much of it is done by large corporations with market power, many believe that this redistribution is bad for societyIf price discrimination redistributes income from consumers to stockholders and managers, it will generate some increase in the degree of inequality in societyDistribution Effect

33、s of Price DiscriminationOne often-cited example, however, suggests that redistributional effects may have net social benefitsPhysicians are among the largest beneficiaries of price discrimination. Doctors routinely discriminate between high- and low-income patients or those with and without good in

34、suranceDiscrimination helps explain why doctors have such high incomesDistribution Effects of Price DiscriminationPrice discrimination can have positive or negative effects on competition. Much depends on whether the discrimination is done by small fringe firms or large dominant firms, and whether i

35、t is sporadic or systematicAt one extreme, if discrimination is done by fringe firms in a sporadic attempt to gain additional sales, then the impact is positiveEffect on CompetitionExamples of price discrimination stimulating competition are easy to identifyA firm may temporarily cut its price in on

36、e geographic area to find out if demand is elastic. If the firm discovers that demand is more elastic than expected, the discrimination could result in a permanent across-the-board price reductionSupermarket chains may cut prices in some areas to induce customers to try their stores. Such price cuts

37、 are often veryEffect on CompetitionThe mobile phone industry provides a good recent example of sporadic price discrimination.AT&T and Sprint seem to change their price structures for each customer in an effort to pry business away from Verizon. Some price discrimination in the airline industry has

38、also been pro-competitiveOn the other extreme, systematic price discrimination by dominant firms can reduce competition by entrenching the positions of the dominant firm(s)Effect on CompetitionConcepts of price discrimination價格歧視 (price discrimination)存在于兩種情況中:當一個企業(yè)在提供成本相同的同樣產品時向不同的消費者收取不同的價格，或者在產品成

39、本不同的情況下面對不同的消費者收取同樣的價格一般來講，只要是面向不同的消費者制定與成本不成比例的價格就是價格歧視換言之，價格歧視發(fā)生于不同的消費者面對不同的價格一成本邊際的情況下價格歧視：廠商將同一商品對不同消費者制定不同的價格。（讓愿意出高價的人用高價買，讓愿意出低價的人以低價買）廠商為何愿意采取價格歧視的做法：與制定單一價格相比，能夠增加利潤價格歧視的定義、作用及條件廠商具有市場勢力（是覓價者）能夠有效區(qū)分消費者的支付意愿，如國外大學學費的價格歧視 （獎學金）限制轉售服務法律和規(guī)章價格歧視的定義Concepts of price discrimination價格歧視的例子兩個航空公司旅客為

40、同一航班的經濟艙支付不同的費用，但是兩個旅客不在同一天乘坐經濟艙支付不同的費用就不是價格歧視一個律師對一個需要準備30分鐘的案件和一個需要準備8小時的案件收取相等的費用商場對于同樣的牛仔褲購買第二件比購買第一件打5折Concepts of price discrimination理解價格歧視有幾個重點。最重要的一點是歧視只有在市場控制力存在時才發(fā)生如果兩個買者在完全競爭市場對同樣的商品制定不同的價格，消費者將只會從價格較低的銷售者那里購買多數情況下，價格歧視的存在暗示了帕累托效率的缺乏;因為不同的消費者面對不同的邊際替代率 (MRS)，達不到交易的有效性Types of price discr

41、imination經濟學家把價格歧視分為三種主要的類型:第一級價格歧視、第二級價格歧視和第三級價格歧視第一級價格歧視(first-degree price discrimination) 也通常稱為完全價格歧視 (perfect discrimination)，每個消費者支付他們對該商品的保留價格，即他們愿意為商品付出的最高價格第二級價格歧視(second-degree price discrimination)，廠商對消費者提供相同的價目表，消費者自己選擇不同的價格類別第三級價格歧視 (third-degree price discrimination)， 依賴于企業(yè)有效地根據消費者的需求彈

42、性進行分組的能力。與第二級價格歧視不同，在第三級價格歧視中，消費者是被廠商分入某組而不能自己選擇進入另一組Types of price discrimination第一級價格歧視在第一級價格歧視下，每個消費者都為壟斷的商品支付他或她所愿意支付的最高價格；因此，壟斷者在任何可能的情況下都偏向于用第一級價格歧視下圖顯示，市場中需求曲線是P=10-Q，產品成本是MC=AC=2元。在這樣的市場中，第一級價格歧視需要第一單位商品以9元的價格出售，第二單位產品以8元的價格出售，第三單位商品以7元的價格出售，以此類推，直到第八單位商品以P=MC=2元的價格出售第一級價格歧視在第八單位商品售出時帶來了44元的

43、總收益。第九單位商品將不會售出，因為消費者的1元的保留價格低于邊際成本Types of price discrimination在第一級價格歧視中，每單位商品都以消費者所愿意支付的最高價格出售第一單位商品以9美元的價格出售，第二單位商品以8美元的價格出售，第三單位商品以7美元的價格出售，直到第八單位商品以2美元的價格出售?？偸找娴扔?+8+7+6+5+4+3+2=44美元沒有消費者剩余，但是生產者剩余是圖中三塊灰色陰影區(qū)域之和X+Y+Z Types of price discrimination在第一級價格歧視中，每單位商品都以消費者所愿意支付的最高價格出售。沒有消費者剩余，但是生產者剩余是圖

44、中三塊灰色陰影區(qū)域之和X+Y+Z要確定價格歧視的福利效應，就有必要比較價格歧視下的消費者剩余和生產者剩余的總和和沒有價格歧視時的消費者剩余和生產者剩余的總和消費者剩余是0，生產者剩余是由X+Y+Z組成。如果企業(yè)沒有實施價格歧視，對所有的消費者都以同一價格出售商品，那么利潤最大化的銷售量是4單位，價格是6元，因此總收益是24元Types of price discrimination這一價政策下，消費者剩余等于區(qū)域X，生產者剩余等于區(qū)域Y。因此福利損失是區(qū)域Z。由于消除價格歧視會導致福利損失Z，第一級價格歧視增加了福利在第一級價格歧視的情況下，分配效率能夠實現，因為在最后一單位商品進行交易時價格

45、等于邊際成本每一個愿意支付的價格比邊際成本高的消費者都能獲得商品。帕累托效率在第一級價格歧視中也實現了，因為一個消費者不必傷害其他消費者就可以達成商品交易微軟利用第一級價格歧視的嘗試 在2002午微軟沒有與法庭簽訂同意判決書之前，它的產品壟斷了基于英特爾的個人計算機 (PC)操作系統(tǒng)，這使得它有能力使用第一級價格歧視將它的操作系統(tǒng)授權給計算機制造商，如戴爾、IBM、惠普。曾經，每款微軟產品的授權是單個簽署的，并且每個被許可單位在其計算機上安裝微軟操作系統(tǒng)所支付的價格是不同的。 微軟要求計算機制造商商議對最小數量授權所支付的費用，這個最小數量通常大于或等于預期的計算機制造商的出貨量。如果一家制造

46、商計劃一年出貨lOOOOO 臺計算機，它就要同意支行一筆最小數量為100000臺的單獨的協(xié)議授權費。更引人注目的是，即使制造商所銷售的計算機沒有安裝微軟操作系統(tǒng)，它也要向微軟支付特許使用費!如果出貨量少于lOOOO0臺，它仍然要向微軟支付l00000 臺的授權費。如果出貨量多于100000 臺，被授權單位要支付多出部分的每臺的單獨的特許使用費。再一次，被授權單位支付的費用不考慮出貨的商品是否安裝了微軟的操作系統(tǒng)。微軟利用第一級價格歧視的嘗試 授權的時限通常是兩年。另外，微軟試圖通過主動提供一個更低的每臺出貨費用來設置比預期出貨量更高的最小數量的授權。到了年底，被許可者通常還有未使用的援權。但是

47、微軟只允許被許可者將這些授權帶到下一年。這樣就為計算機制造商創(chuàng)造了在下一年生產的機器上安裝微軟操作系統(tǒng)的動力。 微軟對安裝非微軟操作系統(tǒng)征收罰款。比如說某個制造商使用了大量的非微軟操作系統(tǒng)，就可能會被禁上執(zhí)行前-午預留的授權，或者被要求在未來同意一個更高的最小授權數量。另外，扶術支持服務會對安裝非微軟操作系統(tǒng)的制造商有所制約。最后，微軟提高了那些安裝了非微軟-DOS操作系統(tǒng)的企業(yè)在它們的某些計算機上安裝Windows系統(tǒng)的價格。 這些政策帶來的聯(lián)合效應是每個計算機制造商為安裝微軟操作系統(tǒng)支付不同的價格。微軟政策是從計算機制造商那里得到最大量的消費者剩余的一種嘗試，也是利用用第一級價格歧視的一種

48、嘗試Types of price discrimination第二級價格歧視在第二級價格歧視下，廠商為所有消費者提供同樣的價目表，消費者自己選擇不同的價格類別盡管消費者支付不同的價格，但每個消費者在同樣的價格類別中購買商品的價格是相等的廠商在其知道不同的消費者有不同的保留價格的情況下利用第二級階格歧視。但是廠商不能辨別每個消費者的類型或者說辨別的成本太高Types of price discrimination企業(yè)為所有消費者提供同樣的價目表，讓消費者自選不同的價格種類二級價格歧視的基本形式區(qū)時定價：旺季機票價格和景點門票、卡拉OK歌廳的收費，飯店的午餐價和晚餐價優(yōu)惠券數量折扣：根據購買數量不

49、同收取不同價格二部定價：手機話費的收取Types of price discrimination第二級價格歧視航空公司通常向所有消費者提供關于同一航班的一系列不同收費選擇，這些收費選擇依賴于許多現實因素，包括什么時候購買機票，旅客在返程前在他或她的目的地停留多長時間必勝客通常對第一份披薩餅收取10美元的價格，而對第二份僅收取5美元。在這個例子中，消費者購買一份披薩餅時支付10美元，但是購買兩份時每份只需支付7.5美元Types of price discrimination假如一條名牌牛仔褲的價格是MC=AC=20美元，并且提供一個數量折扣。消費者購買一條的價格是80美元，購買第二條的價格是6

50、0美元，購買第三條的價格是40美元，購買第四條的價格是20美元給定這一定價結構，一家專賣店每天在這四種價格類別的每一類別上銷售牛仔褲給10位顧客所有的40位顧客購買第一條牛仔褲的價格都是80美元;30位顧客購買第一條的價格都是80美元，購買第二條的價格都是60美元;20位顧客購買第一條的價格都是80美元，購買第二條的價格都是60美元，購買第三條的價格都是40美元;10位顧客購買第一條的價格都是80美元，購買第二條的價格都是60美元，購買第三條的價格都是4O美元，購買第四條的價格都是20 美元Types of price discrimination價格（美元）相應價格下的數量總銷量804040

51、6030704020902010100實施第二級價格歧視的牛仔褲需求 上表顯示了牛仔褲的日需求量。總共100條褲子被售出并且總收益是6000 (=3200+1800+800+200)美元Types of price discrimination圖(a)顯示了名牌牛仔褲實施第二級價格歧視時的需求曲線。陰影部分的面積總和A+B+C+D 代表了總收益并且等于6000美元。圖(b)中，消費者剩余是W+X+Y+Z四個陰影部分面積的總和生產者剩余是A+B+C三個陰影部分面積的總和Types of price discrimination圖(a)中的需求曲線不能與不存在價格歧視時的牛仔褲的需求曲線相比較。沒

52、有價格歧視時，如果牛仔褲以每條20美元的價格為所有牛仔褲定價，它可能會售出多于100條。因此不存在價格歧視時的需求曲線就會位于圖(a)需求曲線的右側與第一級價格歧視相比，在第二級價格歧視的情況下，存在一些消費者剩余。因為銷售者不能準確地辨別每個消費者的每個需求，所以它不能通過市場獲得全部的消費者剩余優(yōu)惠券的使用和第二級價格歧視 第二級價格歧視的一個例子是打折優(yōu)惠券的使用。在2003年廠商印制了價值超過2500億美元的優(yōu)惠券。消費者兌換了大約價值30億美元優(yōu)惠券的商品，即發(fā)行的優(yōu)惠券的1.2%。優(yōu)惠券的平均面值是85美分。除了廠商外，零售商也越未越多邊使用優(yōu)惠券，2003年46%的零售商提供某種

53、優(yōu)惠券。 優(yōu)惠券對于所有消費者都有效。只有一小部分的優(yōu)惠券能得到兌換，一些消費者使用優(yōu)惠券遠多于其他人，對此的解釋是時間的機會成本。人們需要在使用優(yōu)惠券所得到的節(jié)省與獲得和使用優(yōu)惠券的機會成本之間進行權衡。這些機會成本也括搜集(例如在雜志、報紙和網絡中尋找)、組織、取得和兌換優(yōu)惠券的成本。 理論上講，與使用優(yōu)惠券相關的節(jié)省對于所有使用者都是等同的，具有較低的時間機會成本的消費者通常具有較低的使用優(yōu)惠券的成本，因此會使用更多的優(yōu)惠券。優(yōu)惠券的使用和第二級價格歧視 使用優(yōu)惠券的人比不使用優(yōu)惠券的人支付更低的價格，廠商只有在那些使用優(yōu)惠券的人與不使用優(yōu)惠券的人相比有更高的需求彈性的情況下才能使利潤增

54、加。 在一個精心設計的關于優(yōu)惠券使用的實證研究中，納拉森漢發(fā)現使用優(yōu)惠券的人比不使用優(yōu)惠券的人有更高的需求彈性。因此，當廠商能夠利用優(yōu)惠券來對使用者和非使用者進行價格歧視時，利潤會增加。納拉森漢還發(fā)現在這些產品種類中高價的品牌比低價的品牌提供了更多的優(yōu)惠券節(jié)省，較大的型號(較大的盒子或者罐子)比較小的型號提供更少的節(jié)省。 布拉特伯格等人研究了家庭可能利用優(yōu)惠券來購買五種產品:鋁箔、蠟紙、頭痛藥、清潔液和面巾紙。他們把消費者分成優(yōu)惠傾向型和非優(yōu)惠傾向型。全職家庭主婦(即失業(yè)的家庭主婦)比有工作的家庭主婦 (即就業(yè)的家庭主婦)更加傾向于優(yōu)惠交易。優(yōu)惠券的使用和第二級價格歧視 上述調查結果與理論是一

55、致的，全職家庭主婦的時間機會成本更低，因此更傾向于獲取優(yōu)惠券并且尋找便宜貨。 布拉特伯格等人在理論上指出汽車和房子的所有權也會影響優(yōu) 惠的傾向性。 由于交通成本是家庭交易成本的重要因素，有車的家庭有較低的交易成本并且能夠更經常地到更多的商店利用專門的優(yōu) 惠。與租房者相比，房屋主人應該具有優(yōu)惠傾向性。 與這些理論相一致，布拉特伯格等人發(fā)現車和房子的所有權很大程度上影響了優(yōu)惠傾向性。超過35%的有車和房子的家庭是優(yōu)惠傾 向型的；與此相對應的是，只有20.5%的沒有車和房子的家庭是優(yōu)惠傾向型的。第二級價格歧視的福利效應第二級價格歧視的福利影響是非常復雜的。例如，航空公司的第二級價格歧視。航空公司通常

56、對不同類型的機票設定不同的價格。如對在目的地停留一周及以上的度假旅客和在目的地停留一天的商務旅客之間進行價格歧視。假設一家航空公司在它的從紐約到洛杉礬的航班上收取不同的費用，無限制的往返機票是749美元；在洛杉礬至少停留兩周，假期優(yōu)惠費用是400美元；商務旅客愿意支付最高800美元往返機票，在周二到達洛杉礬并在周三返回，但是商務旅客愿意支付的至少停留兩周的往返票費用最高為450美元。然而，度假游客愿意為至少停留兩周的機票最多支付400美元，而對只停留一天的機票沒有任何興趣。Types of price discrimination第二級價格歧視的福利效應如果這個航空公司計算出它的每個旅客的往返

57、機票的邊際成本是100美元，那么對無限制機票收取800美元和對至少停留兩周的機票收取400美元的價格，該航空公司可以賺取1200-200=1000美元的生產者剩余。消費者剩余等于0。因此，價格歧視下的總的生產者剩余和消費者剩余等于1000+0=1000美元。如果價格歧視不可能實現或者違法，那么利潤最大化的策咯就是所有旅客均支付800美元，生產者剩余為800-100=700美元。只有商務旅客乘飛機到洛杉礬，度假旅客待在家里、開車或者乘火車出游。價格歧視下總的生產者剩余和消費者剩余是1000美元，顯著高于沒有價格歧視時的700美元。很明顯此案例中價格歧視增進了福利。Types of price d

58、iscrimination第二級價格歧視的福利效應與統(tǒng)一的價格政策相比，第二級價格歧視可能削減福利。假設商務旅客愿意為一張周二到達洛杉礬周三返回的往返機票最高支付800美元，但是愿意為至少停留兩周的往返機票最高支付400美元。度假旅客愿意為無限制的機票最高支付650美元，但是只愿為至少停留兩周的往返機票最高支付600美元。在價格歧視下，該航空公司對商務旅客和度假旅客分別收取800美元和600美元的價格。沒有消費者剩余，航空公司的生產者剩余等于(800+600)-200=1200美元，沒有價格歧視時，該航空公司可以對無限制機票定價650美元，售出兩張機票，獲得的生產者剩余為6502-200=11

59、00美元。另外，商務旅客可能得到的消費者剩余800-650=150美元。Types of price discrimination第二級價格歧視的福利效應沒有價格歧視時的生產者剩余和消費者剩余之和等于1100-150=1250 美元，比價格歧視下的剩余總和1250美元多。在這個例子里，第二級價格歧視削減了福利。在價格歧視下福利削減50美元的原因是，航空公司對商務旅客收取的費用從650美元提高到800美元，費用的提高消除了沒有價格歧視時的消費者剩余150美元。在價格歧視下，商務旅客消費者剩余減少的l50美元比航空公司生產者剩余增加的l00美元多。三級價格歧視如果購買者的特征是可以觀察到的，企業(yè)可

60、以將目標顧客劃分為幾個群體，對不同的消費者群體制定不同的價格，也稱做市場分割價格歧視的形式：地理位置企業(yè)通常對需求價格彈性高的消費者制定低價，對需求價格彈性低的消費者制定高價Types of price discrimination第三級價格歧視在第三級價格歧視下，企業(yè)能根據消費者不同的需求彈性把他們分成兩組或者更多的組。消費者被廠商分入某一組并且不能自選進入另外一組。只要廠商能在任意給定的價格下根據消費者不同的需求彈性分辨組別，它所實行的價格歧視就能增加利潤例如，假定一個大劇院知道它面對兩種需求曲線，一種是65歲及以上的老年人的需求曲線，另一種是65歲以下的成年人的需求曲線。為了達到利潤最大