2. slide 1Monopoly MONOPOLY A monopoly is a firm which is the sole producer of a good or service for which there are no close substitutes. The monopolist’s demand curve is the same as the market demand curve. The firm must have some way to keep prospective entrants out of the industry, i.e., there must be barriers to entry.

3. slide 2Monopoly BARRIERS TO ENTRY Barriers to entry prevent other firms from entering an industry in which a monopolist may be earning profit. Government franchises Patents and copyrights Economies of scale Ownership of a scarce input

4. slide 3Monopoly Because the demand curve the monopolist sees is negatively sloped, the monopolist can choose price as well as the quantity of output. (Price and quantity sold are linked by the demand curve. The demand curve sets the limit that can be charged for each quantity produced.)

5. slide 4Monopoly REVENUE CURVES FOR A MONOPOLIST The market demand curve for a good is the firm’s average revenue curve.

6. slide 5Monopoly The demand curve shown here is the market demand curve for cable TV hookups in East Lansing. Because the Ripoff Cable TV Co. has an exclusive franchise, the market demand curve is also the firm’s average revenue curve. (AR = price) $/Q Q demand p = $52/mo. 7 Thousand hookups To sell 7,000 hookups per month, they can charge $52. per hookup per month

7. slide 6Monopoly From the demand curve we can find the firm’s total revenue curve (TR as a function of Q). Total revenue is price times quantity. We can then compare total revenue with total costs at each output to find the output and price where profits are maximized. $/Q Q AR = demand p = $68/mo. When 3,000 hookups are sold, they can charge $68 and the total revenue from sales is $204 thousand. Thousand hookups 3

8. slide 7Monopoly Here are other points on the demand curve and some corresponding amounts of total revenue. Fill in the remaining values for TR. QP (=AR)TR 0800 176 272144 368204 464256 560 300 656 336 752 848 944 1040 1136

9. slide 8Monopoly QP (=AR)TR 0800 176 272144 368204 464256 560300 656336 752364 848384 944396 1040400 1136396

10. slide 9Monopoly TR Q 0 50 100 150 200 250 300 350 400 450 02468101214 Plot the remaining points on the TR curve. Hidden slide

11. slide 10Monopoly

12. slide 11Monopoly Here’s the demand curve with the corresponding total revenue curve. Notice that the TR curve is not a straight line! D=AR TR

13. slide 12Monopoly Here is the total cost curve of the Ripoff Cable TV Co. QTC 010 130 254 382 4114 5154 6204 7266 8342 9434 10546 11682

14. slide 13Monopoly We can put the total revenue and total cost curves together to find total profit. Compute the remaining values for profit. Profit = TR - TC QTRTCProfit 0010-10 1763046 214454 320482 4256114 5300154 6336204132 736426698 838434242 9396434-38 10400546-146 11396682-286 Hidden slide

15. slide 14Monopoly We can put the total revenue and total cost curves together to find total profit. Profit = TR - TC QTRTCProfit 0010-10 1763046 21445490 320482122 4256114142 5300154146 6336204132 736426698 838434242 9396434-38 10400546-146 11396682-286

16. slide 15Monopoly Profit is maximized here at 5,000 units of output. The same problem can be solved by the marginal/ average approach. TR TC Q PROFIT Q

17. slide 16Monopoly For a monopolist, average revenue is declining as output increases so marginal revenue must be less than average revenue. It is important to understand why MR is less than AR in this case.

18. slide 17Monopoly Compute the missing values of Marginal Revenue. QP (=AR)TRMR 0800 176 27214468 3 20460 46425652 560300 656336 36 752364 848384 944396 1040400 1136396 Hidden slide 44 MR = (300-256)/ (5-4)

19. slide 18Monopoly QP (=AR)TRMR 0800 176 27214468 3 20460 46425652 56030044 65633636 75236428 84838420 94439612 10404004 1136396-4 Note that MR is always less than price. Plot the MR curve.

20. slide 19Monopoly $/Q Q D=AR MR -10 0 10 20 30 40 50 60 70 80 02468101214 Hidden slide

21. slide 20Monopoly

22. slide 21Monopoly Marginal revenue is always less than price for a monopolist because the firm must reduce price in order to sell more. Demand or AR Q $/Q p p’ qq+1 To sell an extra unit of output, the monopolist must lower price, thus losing the shaded area on all of the previous units sold at a price of p.

23. slide 22Monopoly Demand or AR Q $/Q p p’ qq+1 These rectangles have the same area. So this area is MR, which is less than p’. An increase in sales of one unit requires a reduction in price.

24. slide 23Monopoly -5 10 25 40 55 70 85 100 115 130 024681012 $/Q Q MC AC AR=demand MR Thousand hookups Here are the average and marginal cost and revenue curves for the same problem. What values of output and price maximize profit for the Ripoff Cable TV Co.?

25. slide 24Monopoly -5 10 25 40 55 70 85 100 115 130 024681012 Q MC AC AR=demand MR Thousand hookups In this case the best output is 5,000 hookups, and the best price is $60 per month. Choose output where MC = MR Then choose price by going to the demand curve.

26. slide 25Monopoly -5 10 25 40 55 70 85 100 115 130 024681012 $/Q Q MC AC AR=demand MR Thousand hookups To compute the amount of profits in monopoly, find average profit (AR- AC) at the profit maximizing output, and multiply by Q. The shaded area is total profits.

27. slide 26Monopoly Summary of monopoly pricing: To maximize profit a monopolist should choose output where MC = MR. Price is determined from the demand curve.

28. slide 27Monopoly Do monopolists choose the best output and price from society’s point of view? Another way to ask the question is whether the monopolist operates in society’s interest, and if not, what can be done to remedy the evils of monopoly.

29. slide 28Monopoly This requires us to formulate some rule for determining when social welfare is improved by some change, and when social welfare is maximized. The rule we'll use is that social welfare is measured by the sum of producer and consumer surplus. So society ought to produce where the sum of producer and and consumer surplus is as large as possible.

30. slide 29Monopoly Producer Surplus PS is the difference between what producers take in (TR) at a given level of production and the minimum amount they would accept for producing that level of output.

31. slide 30Monopoly MC P’ $/Q Q Q’ AT P’ AND Q’, THE PS IS THE SHADED AREA.

32. slide 31Monopoly Consumer Surplus CS is the difference between what consumers pay for a given quantity and the maximum amount they are willing to pay.

33. slide 32Monopoly D P’ $/Q Q Q’ AT P’ AND Q’, THE CS IS THE SHADED AREA.

34. slide 33Monopoly MC P’ $/Q Q Q’ AT P’ AND Q’, THE WELFARE IS THE SUM OF THE SHADED AREAS. D

35. slide 34Monopoly THE SUM OF PRODUCER AND CONSUMER SURPLUS IS MAXIMIZED WHERE THE MARGINAL COST CURVE INTERSECTS THE DEMAND CURVE.

36. slide 35Monopoly $/Q Q MC D MR Q* P* Here’s our friendly local monopolist the Ripoff Cable TV Co. of East Lansing. The profit maximizing output is Q*, and the profit maximizing price is p*. The following hidden slides illustrate the computation of surplus at the monopolist’s output, and the deadweight loss due to monopoly. Hidden slide

37. slide 36Monopoly SURPLUS UNDER MONOPOLY $/Q Q P* MC D MR Q* Q P* MC D MR Q* Consumer surplus Producer surplus

38. slide 37Monopoly What is the maximum surplus possible? $/Q Q MC D MR Q* Q P* MC D MR Q* Consumer surplus Producer surplus Maximum surplus Deadweight loss

39. slide 38Monopoly Compare monopoly and socially best outputs $/Q Q P’ MC D MR Q’ Q P* MC D MR Q* Society vs. monopoly

40. slide 39Monopoly GENERAL RULE: The socially best output is where marginal cost equals price -- where the marginal cost curve cuts through the demand curve. When the socially best output is being produced, the right amount of resources are being devoted to the good.

41. slide 40Monopoly We can now see why monopoly is bad: It results in less than the optimal amount of a good being produced. Monopolists produce too little of a good and sell it at too high a price.

42. slide 41Monopoly $/Q Q MC D MR Q’ P’ Note that at the socially best output and price, the firm is still able to earn positive profits (p>AC). This shows that it is not the level of profits that economists object to about a monopolist’s behavior. AC Profits at socially best output

43. slide 42Monopoly Producing where marginal cost equals price in order to maximize social welfare is called marginal cost pricing.

44. slide 43Monopoly DEFINITIONS: Marginal social benefit (MSB): The MSB is the increase in social welfare that results from consuming another unit of a good. Marginal social cost (MSC): The MSC is the cost to society of producing another unit of a good. Another method for finding the best output takes a different approach, using the concepts of marginal social benefit and marginal social cost.

45. slide 44Monopoly OPERATING PRINCIPLE: Social welfare will be maximized if a good is produced (and consumed) up to the point where marginal social benefit equals marginal social cost. MSB,MSC QUANTITY MSC MSB Q SOCIETY

46. slide 45Monopoly The problem with this rule is that we don’t have any foolproof way of measuring MSB and MSC. But all is not lost!

47. slide 46Monopoly Suppose it were true that a good’s price is a good measure of MSB. And suppose that a firm’s marginal cost curve is a good measure of MSC. Then MSB = MSC boils down to producing where MC = P, our rule for welfare maximization.

48. slide 47Monopoly $/Q Q MC = MSC D = MSB MR Q society P society AC If the firm’s MC curve is a good measure of MSC, and if its demand (AR) curve is a good measure of MSB, then the best output will is where MC = P.

49. slide 48Monopoly How could this work in practice? In regulating a monopolist we would need information on market demand and on the firm’s marginal cost at each level of output. We could make the monopolist produce the best output with a series of taxes or subsidies, or even by direct regulation (price setting by a regulator).

50. slide 49Monopoly $/Q Q MC = MSC D = MSB MR Q society P society AC In this case equality between MSC and MSB means having marginal cost equal to price (MC = P).

51. slide 50Monopoly Monopoly summary To maximize profit, the monopolist will produce where MC = MR. From society’s point of view monopolists produce too small an output, and sell it at too high a price. The best output from society’s point of view is where MC = P. We can measure the deadweight loss due to monopoly as the (roughly) triangular area between the MC curve and the demand curve.

52. slide 51Monopoly Price Discrimination Definition:A situation in which the producer sells different units of the same good to different consumers at different prices. The idea here is that some consumers pay high prices and some pay lower prices for the same good or service. To be successful, a producer must have some way to keep the markets separate.

53. slide 52Monopoly Price discrimination example Suppose a monopolistic producer of electricity sells in two markets, residential and commercial. The demand curves differ in the two markets. How should any quantity be divided between the markets if total revenue is to be maximized?

54. slide 53Monopoly Rule: To maximize TR, sell quantities in the two markets so that the marginal revenue in market 1 equals marginal revenue in market 2. Then set prices accordingly.

55. slide 54Monopoly Reasoning: If MR in one of the markets were higher, then a unit of output could to switched from the lower to the higher MR market. There would be an increase in TR as a result.

56. slide 55Monopoly But how much total output should the firm produce? It should produce where MR equals MC.