Monopoly　獨占、壟斷.

Presentation on theme: "Monopoly　獨占、壟斷."— Presentation transcript:

1 Monopoly　獨占、壟斷

2 獨占的來源 AR(P) 與MR的分離 獨占廠商的最適產量 差別取價 獨占的福利損失

3 Most of us use Microsoft Windows to run our computers
Most of us use Microsoft Windows to run our computers. Microsoft isn’t a price taker like the firms in perfect competition. How does a firm like Microsoft decide the quantity to produce and the price to charge?

4 Market Power Market power and competition are the two forces that operate in most markets. Market power is the ability to influence the market, and in particular the market price, by influencing the total quantity offered for sale. A monopoly is an industry that produces a good or service for which no close substitute exists and in which there is one supplier that is protected from competition by a barrier preventing the entry of new firms.

5 純粹、完全獨占： 一產業只有一個供給者且沒有相近的替代品存在，且其他廠商，很難進入市場 No close substitutes
Barriers to entry

6 獨占的來源 進入的障礙（barriers to entry）或成本的優勢 １法律限制（郵局） ２專利（製藥 prozac）
３掌控稀少的資源或生產要素 4 高昂的沈沒成本sunk cost（航空） 5 技術上的優越性（microsoft） 6 規模經濟 7 市場需求衰退

7 自然壟斷 一產業有規模經濟，使單一廠商能以相當低的平均成本生產物（幾乎）足供整市場消費的產量
（相較於生產較少數量的小廠商，他們的AC會較高）

8 natural monopoly an industry in which one firm can supply the entire market at a lower price than two or more firms can. The ATC curve is still sloping downward when it meets the demand curve.

9 Market Power One firm can produce 4 units of output at 5 cents per unit. Two firms can produce 4 units—2 units each—at 10 cents per unit.

10 A Single-Price Monopoly’s Output and Price Decision
Price and Marginal Revenue A monopoly is a price setter, not a price taker like a firm in perfect competition. The reason is that the demand curve for the monopoly’s output is the market demand curve. To sell a larger output, a monopoly must set a lower price.

11 MR < P, P=AR Total revenue, TR, is the price, P, multiplied by the quantity sold, Q. Marginal revenue, MR, is the change in total revenue that results from a one-unit increase in the quantity sold. For a single-price monopoly, marginal revenue is less than the price at each level of output. That is, MR < P

12 單一訂價的廠商，價格滑落時，不但邊際出售的單價下降，連原先能出售的產品價格也下降，所以邊際收益低於價格
MR < P

13 marginal revenue 比較p=16，q=2 以及p=14，q=3
It loses $4 of total revenue on the 2 units it was selling at $16 each. And it gains $14 of total revenue on the 3rd unit.So total revenue increases by $10

14 MR MR < P at each quantity. 3rd haircut P=14 MR=14*3-16*2
The marginal revenue curve, MR, passes through the red dot midway between 2 and 3 units and at $10. MR < P at each quantity. 3rd haircut P=14 MR=14*3-16*2 =14-2*2=10

15 Marginal Revenue and Elasticity 1
If demand is elastic, a fall in price brings an increase in total revenue. The rise in revenue from the increase in quantity sold outweighs the fall in revenue from the lower price per unit, and MR is positive.

16 Marginal Revenue and Elasticity 2
If demand is inelastic, a fall in price brings a decrease in total revenue. The rise in revenue from the increase in quantity sold is outweighed by the fall in revenue from the lower price per unit, and MR is negative.

17 Marginal Revenue and Elasticity 3
If demand is unit elastic, a fall in price does not change total revenue. The rise in revenue from the increase in quantity sold equals the fall in revenue from the lower price per unit, and MR = 0.

18 Total revenue is maximized when marginal revenue is zero.
A single-price monopoly never produces an output at which demand is inelastic, i.e. MR<0 .

19 價格會影響需求量，因此無法以高價出售很多數量，故需考慮選擇利潤極大化的數量
MR=MC MR= △TR／△Q AR=TR／Q ＱD=20-Ｐ, P=20-ＱD TR=P*Q=(20-Q)*Q MR= △TR／△Q=20-2Q

20 A Single-Price Monopoly’s optimal Output
The monopoly faces the same types of technology constraints as the competitive firm, but the monopoly faces a different market constraint. The monopoly selects the profit-maximizing level of output in the same manner as a competitive firm, where MR = MC.

21 A Single-Price Monopoly’s Price Decision
The monopoly sets its price at the highest level at which it can sell the profit-maximizing quantity. The monopoly may earn an economic profit, even in the long run, because the barriers to entry protect the firm from market entry by competitor firms.

22 profit-maximizing choices of a single-price monopolist.
the monopoly sets the quantity produced at the level that maximizes total revenue minus total cost.

23 A Single-Price Monopoly’s profit
Q*=3 P*=14, ATC=10 Economic profit =($14-10)*3 =$12 The classic monopoly diagram The classic monopoly diagram, Figure 12.4b provides a good opportunity to tell your students about the contribution of one of the most brilliant economists of the 20th century, Joan Robinson. This diagram first appeared in her book, The Economics of Imperfect Competition, published in 1933 when she was just 30 years old. You can learn more about Joan Robinson at (or use the link on the Economics Place Web site). Women are still not attracted to economics on the scale that they’re attracted to most other disciplines. So the opportunity to talk about an outstanding female economist shouldn’t be lost. Joan Robinson was a formidable debater and reveled in verbal battles, a notable one of which was with Paul Samuelson on one of her visits to MIT. Anxious to make and illustrate a point, Samuelson asked Robinson for the chalk. Monopolizing the chalk and the blackboard, the unyielding Robinson snapped, “Say it in words, young man.” Samuelson meekly obeyed. This story illustrates Joan Robinson’s approach to economics: work out the answers to economic problems using the appropriate techniques of math and logic, but then “say it in words.” Don’t be satisfied with formal argument if you don’t understand it. Your students will benefit from this story if you can work it into your class time.

24 Equilibrium if the firm is in perfect competition
where the quantity demanded equals the quantity supplied at quantity QC and price PC.

25 Single-Price Monopoly and Competition Compared
Equilibrium price for a monopoly, PM, occurs on the demand curve at the profit-maximizing quantity.

26 Efficiency Comparison
competitive equilibrium is efficient: MB = MC.

27 competitive equilibrium
The sum of the two surpluses is maximized and the efficient quantity is produced.

28 Monopoly is inefficient
because price exceeds marginal cost so marginal benefit exceeds marginal cost. Monopoly is inefficient. The inefficiency of monopoly is one of the key propositions in this chapter. Because P > MR, and because MR = MC, P > MC , single-price monopoly under-produces and creates deadweight loss. Rent seeking uses further resources so potentially the social cost of monopoly is the sum of the deadweight loss and the economic profit that a monopoly might earn. Adam Smith described the situation thus: “People in the same trade seldom meet together, even for merriment and diversion, but the conversation ends in some contrivance to raise prices.”

29 Monopoly is inefficient
On all output levels for which marginal benefit exceeds marginal cost, a deadweight loss is incurred. 無謂的損失 Monopoly is inefficient. The inefficiency of monopoly is one of the key propositions in this chapter. Because P > MR, and because MR = MC, P > MC , single-price monopoly under-produces and creates deadweight loss. Rent seeking uses further resources so potentially the social cost of monopoly is the sum of the deadweight loss and the economic profit that a monopoly might earn. Adam Smith described the situation thus: “People in the same trade seldom meet together, even for merriment and diversion, but the conversation ends in some contrivance to raise prices.”

30 Redistribution of Surpluses
Monopoly redistributes a portion of consumer surplus by changing it to producer surplus.

31 Rent Seeking 1 The social cost of monopoly may exceed the deadweight loss through an activity called rent seeking, which is any attempt to capture consumer surplus, producer surplus, or economic profit..

32 Rent Seeking 2 Rent seeking is not confined to a monopoly.
There are two forms of rent seeking activity to pursue monopoly: Buy a monopoly—transfers rent to creator of monopoly. Create a monopoly—uses resources in political activity.

33 人為的壟斷 以法律的規定，如証照制，或專利的給予，所造成的獨占

34 Rent-Seeking Equilibrium
The resources used in rent seeking can exhaust the monopoly’s economic profit and leave the monopoly owner with only normal profit.

35 deadweight loss from rent seeking
Average total cost increases and the profits disappear to become part of the enlarged deadweight loss from rent seeking.

36 Price Discrimination 差別取價
Price discrimination is the practice of selling different units of a good or service for different prices. 差別取價(price discrimination)是指獨占廠商為了獲取最大利潤，在生產成本不變情形下，將同一產品依消費者、市場、地區或購買量的不同，索取不同價格的現象。例如：公共汽車及遊樂區等，常將售票分為全票、學生票及半票；台電公司將用戶分為家庭、商業、工業等用電，並依不同的用電戶收取不同費率。 Price discrimination may not be fair, but it is efficient Be sure that the students understand that aside from equity considerations, resources will be allocated more efficiently in a monopoly market under any price discrimination scenario than under a single-price scenario.

37 Conditions for price discrimination
Identify and separate different buyer types 市場區隔、不同的需求彈性 Sell a product that cannot be resold 市場封閉 Price differences that arise from cost differences are not price discrimination.

38 DVD影片分區 全球軟體及硬體大致區分為八大區 區域不同之軟體無法播放，需將機器改為全區才能讀取 區 別 國 家 R1 美國‧加拿大
區　別 國　　　　家 R 美國‧加拿大 R 歐洲‧日本‧南非‧中東 R 韓國‧台灣‧香港‧新加坡‧馬來西亞‧印尼 R 澳洲‧紐西蘭‧中南美洲 R 印度‧非洲 R 中國大陸 R 保留 R 特別國際管轄地區(含飛機或遊艇)

39 區域不同之軟體無法播放，需將機器改為全區才能讀取 區域不同之軟體無法播放，需將機器改為全區才能讀取
                                                                                                     區域不同之軟體無法播放，需將機器改為全區才能讀取                                                                                                                                                                                                          

40 Price Discrimination and Consumer Surplus
Price discrimination converts consumer surplus into economic profit. A monopoly can discriminate Among units of a good. Quantity discounts are an example. (But quantity discounts that reflect lower costs at higher volumes are not price discrimination.) Among groups of buyers. (Advance purchase and other restrictions on airline tickets are an example.)

41 Profiting by Price Discriminating
price discrimination converts consumer surplus into economic profit.

42 Price Discrimination As a single-price monopolist, this firm maximized profit by producing 8 units, where MR = MC and selling them for $1,200 each.

43 Price Discrimination By price discriminating, the firm can increase its profit. In doing so, it converts consumer surplus into economic profit.

44 Perfect Price Discrimination
第一級差別取價 extracts the entire potential consumer surplus and converts it to economic profit.

45 Perfect Price Discrimination
Output increases to the quantity at which price equals marginal cost. Economic profit increases above that earned by a single-price monopoly. Deadweight loss is eliminated.

46 8-3 　差別取價的方法 第一級差別取價 (又稱完全差別取價) 指獨占廠商依據消費者對每一單位產品所願支付的最高價格來收費。 B D

47 8-3 第二級差別取價 (又稱階段訂價法) 指獨占廠商對某一特定數量範圍內的產品索取某一價格，超出此一數量後，每增加某一特定數量的產品，即索取較低的價格，故乃對不同級距範圍內之商品訂立不同價格，剝奪了部分消費者剩餘。 a b

48 指獨占廠商就同一產品，對不同的市場索取不同的價格；對需求彈性較高的消費者收取較低的價格，而需求彈性較小的則收取較高的價格。如學生票、成人票。
8-3 第三級差別取價 (又稱階段訂價法) 指獨占廠商就同一產品，對不同的市場索取不同的價格；對需求彈性較高的消費者收取較低的價格，而需求彈性較小的則收取較高的價格。如學生票、成人票。

49 第三級差別取價時，如何才能 極大化利潤？ MRa = MRb 彈性小則價格高

50 Efficiency and Rent Seeking with Price Discrimination
The more perfectly a monopoly can price discriminate, the closer its output gets to the competitive output (P = MC) and the more efficient is the outcome. But this outcome differs from the outcome of perfect competition in two ways: The monopoly captures the entire consumer surplus. The increase in economic profit attracts even more rent-seeking activity that leads to an inefficient use of resources.

51 Monopoly Policy Issues
A single-price monopoly creates inefficiency and price discriminating monopoly captures consumer surplus and converts it into producer surplus and economic profit. And monopoly encourages rent-seeking, which wastes resources. But monopoly brings benefits. A quick introduction The treatment of monopoly policy here is brief and designed for the instructor who wants to cover the topic briefly and at this point in the course. Chapter 17 provides a more extensive treatment of regulation and antitrust law. You can cover that chapter, in whole or part, right now if you want to do more on the topic.

52 Gains from Monopoly Product innovation Economies of scale and scope
Patents and copyrights provide protection from competition and let the monopoly enjoy the profits stemming from innovation for a longer period of time. Economies of scale and scope Where economies of scale or scope exist, a monopoly can produce at a lower average total cost than a large number of competitive firms could achieve.

53 Regulating Natural Monopoly
Under natural monopoly, government agencies regulate the monopoly.

54 Price regulations under monopoly
With no regulation, the monopoly maximizes profit. It produces the quantity at which marginal revenue equals marginal cost.

55 marginal cost pricing 1 Regulating a natural monopoly in the public interest sets output where MB = MC and the price equal to marginal cost. This regulation is the marginal cost pricing rule, and it results in an efficient use of resources.

56 marginal cost pricing 2 With price equal to marginal cost, ATC exceeds price and the monopoly incurs an economic loss. If the monopoly receives a subsidy to cover its loss, taxes must be imposed on other economic activity, which create deadweight loss.

57 average cost pricing a regulated natural monopoly might be permitted to price discriminate to cover the loss from marginal cost pricing. Another alternative is to produce the quantity at which price equals average total cost and to set the price equal to average total cost—the average cost pricing rule.

58 是否獨占廠商一定會賺錢？ 視需求而定，如需求很低，仍有可能賠錢
例：微軟第一個operating system要花數百萬美元製造，但接下來的copy只要很少的錢 diminishing cost network effect 用的人愈多，則有愈多相關產品 lock in effect　習慣

59 獨占者的決策 找到使MR=MC之產量Q* 找到Q*對應在需求線上的價格 比較P & AC，賺錢？

60 一個獨占價格、產量的決定

61 P.C. ｖｓ Monopoly monopoly可持續賺取超額利潤 monopoly生產較少而要價較高 P = MC
生產效率：LR會到LAC的最低? 資源配置的效率 獨占廠商可能試圖改變需求 獨占廠商可能改變成本線 獨占可能促進創新 自然獨占時，單一廠商成本較低

62 8-4 　獨占與完全競爭市場的比較 E C B A G F

63 獨占市場的價格歧視 price discrimination
任一產品，廠商出售時，對不同購買者收取不同價格 提供一產品，縱然供給成本不同，售價卻相同

64 100個有錢人，價格忍受上限：$75 1000個窮人，價格忍受上限：$25 如不能歧視：$25 * ( ) = 27500 $75 * =7500 歧視：$25 * * 100 = 32500 價格歧視時，利潤通常較高

65 是否價格歧視都不好？ 醫師對窮苦者收較低診療費 允許廠商收取足以支付成本的價格 有些人可能買到較便宜的產品

66 獨占廠商沒有供給線 由於完全獨占廠商的 AR 為一條負斜率的需求線，且MR位於AR線的下方，若市場的需求狀況改變，AR與MR亦會跟著同時變動。 正因為需求面的變化有無限多種，因此有可能在同一種價格下，獨占廠商會提供不同的產量；或者在相同的最適產量之下，會出現不同的價格，故在獨占市場中，無法畫出一條均衡價格與均衡產量間的固定關係，所以獨占廠商沒有固定的供給線。

67 短期虧損，一定得歇業嗎？ 1.AR>AVC：廠商宜繼續生產 (1) 廠商繼續生產則會有 藍色面積的虧損 CP*BA發生。
8-1 　短期虧損，一定得歇業嗎？ 1.AR>AVC：廠商宜繼續生產 (1) 廠商繼續生產則會有 藍色面積的虧損 CP*BA發生。 (2) 停業負擔的總固定成 本為面積CHKB。 (3) 繼續生產的虧損（藍 色面積）＜停業負擔 的總固定成本，所以 理性的廠商仍會選擇 繼續生產。 營業虧損 B A K E

68 2.AR=AVC：廠商自由決定經營或停業 (1) 廠商繼續生產仍然有藍色面積的虧損CP*BA產生。
8-1 2.AR=AVC：廠商自由決定經營或停業 (1) 廠商繼續生產仍然有藍色面積的虧損CP*BA產生。 (2) 假若選擇停止生產，則每單位產量會有BA的固定成本，因此停業負擔的總固定成本為面積CP*AB。 (3) 因此繼續生產的虧損(藍色面積)＝停業負擔的總固定成本，在此情況下，廠商的總收入只夠回收全部的變動成本，繼續經營與歇業沒有兩樣。 營業虧損 B A E

69 3.AR=AVC：廠商應關門大吉 (1) 廠商繼續生產一定有藍色面積的虧損CP*AB產生。
8-1 3.AR=AVC：廠商應關門大吉 (1) 廠商繼續生產一定有藍色面積的虧損CP*AB產生。 (2) 假若選擇停止生產，則每單位產量會有BK的固定成本，因此停業負擔的總固定成本為面積CHKB。 (3) 由於繼續生產的虧損（藍色面積）＞停業負擔的總固定成本(CHKB)，若繼續經營會連變動成本都無法全部收回，所以理性的廠商應立刻結束營業，以減少損失。 營業虧損 B K A E