1. Chapter 7.1 Monopolistic Competition and Oligopoly Chapter 7.1 Monopolistic Competition and Oligopoly

2. The Continuum of the Market Structure Perfect Competition n=infinity n=1 Monopoly n large Imperfect Competition n= small 2 ~ 8 firms OLIGOPOLY No of firms, n

3. MONOPOLISTIC COMPETITION Assumptions of monopolistic competition Each firm selling a different variety or brand There are many firms – –Act independently – ignore others REACTIONS Equilibrium of the firm Freedom of Entry and Exit There is Symmetry – –New firms affect all old ones equally Assumptions of monopolistic competition Each firm selling a different variety or brand There are many firms – –Act independently – ignore others REACTIONS Equilibrium of the firm Freedom of Entry and Exit There is Symmetry – –New firms affect all old ones equally

4. MONOPOLISTIC COMPETITION Assumptions of monopolistic competition Equilibrium of the firm – –short run Assumptions of monopolistic competition Equilibrium of the firm – –short run

5. Suppose we consider the case of demand for eating out. £ Q O PsPs QsQs The ‘Industry’ Demand Curve looks like this

6. Suppose we consider the case of demand for eating out. £ Q O PsPs QsQs What about an individual restaurant? It is further in And flatter Why?

7. Suppose we consider the case of demand for eating out. £ Q O PsPs QsQs Each restaurant type has a share of the industry But knows that it can only vary its price a little

8. Suppose we consider the case of demand for eating out. £ Q O PsPs QsQs What if a new competitor appears? Demand line shifts in more and flattens more Getting closer and closer to Perfect Competition

9. £ Q O PsPs QsQs So now suppose we have a firm like the blue line … and this restaurant is doing well in the short-run The Balti Story

10. Let’s make the Balti picture bigger £ Q O MR AR  D PsPs QsQs

11. Let’s make the Balti picture bigger £ Q O AC MR AR  D PsPs QsQs MC

12. £ Q O AC MR AR  D PsPs QsQs MC AC s Short-run equilibrium of the firm under monopolistic competition

13. £ Q O AC MR AR  D PsPs QsQs MC AC s Short-run equilibrium

14. £ Q O AC MR D QsQs MC AC s What happens now? New Firms enter What happens to D? So P and Q down P1P1

15. £ Q O AC MR D QsQs MC AC s What happens now? New Firms enter What happens to D? So P and Q down And Super- normal Profits down

16. £ Q O AC MR D QsQs MC AC s What happens now? New Firms enter What happens to D? So P and Q down And Super- normal Profits down

17. What Happens Next? Still Super-Normal ProfitsStill Super-Normal Profits So firms keep enteringSo firms keep entering P keeps falling and Super-normal profits keep falling until….P keeps falling and Super-normal profits keep falling until…. In the LRIn the LR AR = AC and there are no supernormal profitsAR = AC and there are no supernormal profits

18. £ Q O LRAC MR L AR L  D L PLPL QLQL LRMC Long-run equilibrium of the firm under monopolistic competition

19. NOTICE: AR or D curve still slopes downAR or D curve still slopes down So not in perfect competition caseSo not in perfect competition case Still believe have some market power over price and quantityStill believe have some market power over price and quantity But….But…. Competition is such that such power is illusoryCompetition is such that such power is illusory

20. MONOPOLISTIC COMPETITION Assumptions of monopolistic competition Equilibrium of the firm – –short run – –long run – –under-utilisation of capacity in long run Assumptions of monopolistic competition Equilibrium of the firm – –short run – –long run – –under-utilisation of capacity in long run

21. Under-utilisation of capacity in the long run £ Q O LRAC D L under monopolistic competition Q1Q1

22. Under-utilisation of capacity in the long run £ Q O LRAC D L under monopolistic competition Q1Q1 Q2Q2

23. MONOPOLISTIC COMPETITION Limitations of the model – –imperfect information about profits and demand – –difficulty in identifying industry demand curve – –entry may not be totally free – –indivisibilities/local monopolies – –importance of non-price competition   Variety (see box 4.7, p115)   Advertising Limitations of the model – –imperfect information about profits and demand – –difficulty in identifying industry demand curve – –entry may not be totally free – –indivisibilities/local monopolies – –importance of non-price competition   Variety (see box 4.7, p115)   Advertising

24. MONOPOLISTIC COMPETITION Limitations of the model – –imperfect information about profits and demand – –difficulty in identifying industry demand curve – –entry may not be totally free – –Indivisibilities/local monopolies – –importance of non-price competition Limitations of the model – –imperfect information about profits and demand – –difficulty in identifying industry demand curve – –entry may not be totally free – –Indivisibilities/local monopolies – –importance of non-price competition The public interest –comparison with perfect competition

25. Long run equilibrium of the firm under perfect and monopolistic competition £ Q O P1P1 LRAC D L under perfect competition Q1Q1

26. Long run equilibrium of the firm under perfect and monopolistic competition £ Q O P2P2 P1P1 LRAC D L under perfect competition D L under monopolistic competition Q2Q2 Q1Q1

27. MONOPOLISTIC COMPETITION Limitations of the model – –imperfect information about profits and demand – –difficulty in identifying industry demand curve – –entry may not be totally free – –Indivisibilities/local monopolies – –importance of non-price competition Limitations of the model – –imperfect information about profits and demand – –difficulty in identifying industry demand curve – –entry may not be totally free – –Indivisibilities/local monopolies – –importance of non-price competition The public interest –comparison with perfect competition –comparison with monopoly

28. The Continuum of the Market Structure Perfect Competition n=infinity n=1 Monopoly n large Imperfect Competition n= small 2 ~ 8 firms OLIGOPOLY No of firms, n

29. OLIGOPOLY Key features of oligopolyKey features of oligopoly –barriers to entry –interdependence of firms –~What’s s/he up to? –incentives to compete versus incentives to collude

30. Day 1: Suppose initially Monopoly firm in the Industry £ O Q D To make life simple suppose P=200-Q is the demand curve

31. Suppose initially Monopoly firm in the Industry £ O Q D To make life simple suppose P=200-Q is the demand curve, And MC are zero What is the MR curve? 200

32. Suppose initially Monopoly firm in the Industry £ O Q D P=200-Q TR= P.Q TR=[200-Q].Q TR=200Q-Q 2 MR=200-2Q 200

33. Suppose initially Monopoly firm in the Industry £ O Q D P=200-Q TR= P.Q TR=[200-Q].Q TR=200Q-Q 2 MR=200-2Q 200 MR 100 If MR = 0, 200=2Q MC

34. Suppose initially Monopoly firm in the Industry £ O Q D What quantity will this firm supply to the market MR=MC at 100 Q=100 P=200-Q P=200-100 =100 200 MR 100 MC P=100

35. Suppose initially Monopoly firm in the Industry £ O Q D So monopolist supplies half the market in this case (Linear demand, MC=0) 200 MR 100 MC P=100

36. Day 2: Harmony is broken! Suppose now a new firm notices there are unfulfilled customers £ O Q D What will new firm do? 200 MR 100 MC P=100

37. Suppose now a new firm notices there are unfulfilled customers £ O Q D What will new firm do? 200 MR 100 MC P=100 MC 2 It thinks it has demand P=100-Q MR=100-2Q

38. Suppose now a new firm notices there are unfulfilled customers Q D What will new firm do? 200 100 MR 0 MC P=100 MC 2 It thinks it has demand P=100-Q MR=100-2Q It is just looking at this bit of the market Setting MC = MR =0 100=2Q Q=50

39. So now firm 1 is supplying 100 unitsSo now firm 1 is supplying 100 units And firm 2 is supplying 50 UnitsAnd firm 2 is supplying 50 Units Will firm 1 accept that?Will firm 1 accept that? How will it react?How will it react?

40. Day 3: The reckoning £ O Q D Firm 1 sees that 50 people are already being supplied. So its market is P=200-Q –50 P=150-Q 200 MR 100 MC P=100 MC 2

41. Day 3: The reckoning £ O Q D Firm 1 sees that 50 people are already being supplied. So its market is P=200-Q –50 P=150-Q 200 MR 100 MC P=100 150

42. Day 3: The reckoning £ O Q D And MR is now MR=150-2Q So when MR=MC=0 Q=75 200 MR 100 MC P=100 150 75

43. Firm 1 was supplying 100 unitsFirm 1 was supplying 100 units Is Now Supply 75 unitsIs Now Supply 75 units Firm 2 is still producing 50 unitsFirm 2 is still producing 50 units How will firm 2 react to the cut in firm 1’s production?How will firm 2 react to the cut in firm 1’s production?

44. This is essentially the story now £ O Q Market D Firm 1 Supplies 75 Firm 2 Supplies 50 But now Firm 2 sees that there are 125 unsatisfied consumers 200 MR 1 100 MC P=100 MC 2 MR 2 D1D1 D1D1 D2D2

45. Day 4: The Mob Strikes BACK £ O Q D Firm 2 sees that 75 people are already being supplied. So its market now is P=200-Q –75 P=125-Q 200 MR 100 MC P=100 125

46. Day 4: The Mob Strikes BACK £ O Q D And MR is now MR=125-2Q So when MR=MC=0 Q=62.5 200 MR 2 100 MC P=100 125 62.5 125

47. Firm 1 was supplying 100 unitsFirm 1 was supplying 100 units Firm 1 Is Now producing 75 unitsFirm 1 Is Now producing 75 units Firm 2 was producing 50 unitsFirm 2 was producing 50 units Firm 2 is now Producing 62.5 unitsFirm 2 is now Producing 62.5 units Firm 1’s Q is going down as Firm 2 goes UpFirm 1’s Q is going down as Firm 2 goes Up Firm 2’s Q is going Up as Firm 1 goes downFirm 2’s Q is going Up as Firm 1 goes down When will equilibrium occur?When will equilibrium occur?

48. Armageddon £ O Q D 200 100 MC P=100 133.3 133.33 If each firm 2 sees that 66.66 people are already being supplied, then it sees its market as P=200-Q –66.66 P=133.33-Q

49. Armageddon £ O Q D And MR is now MR=133.33-2Q So when MR=MC=0 Q=66.66 200 MR 1 = MR 2 100 MC P=100 133.3 66.66 133.33 If each firm sees that 66.66 people are already being supplied, then P=133.33-Q D 1 =D 2

50. Firm 1 fall from supplying 100 units to 66.66 unitsFirm 1 fall from supplying 100 units to 66.66 units Firm 2 rises from supplying 0 units to 66.66 unitsFirm 2 rises from supplying 0 units to 66.66 units Given that firm 1 is supplying 66.66 units firm 2’s best response is 66.66 unitsGiven that firm 1 is supplying 66.66 units firm 2’s best response is 66.66 units Given that firm 2 is supplying 66.66 units firm 1’s best response is 66.66 unitsGiven that firm 2 is supplying 66.66 units firm 1’s best response is 66.66 units EQUILIBRIUMEQUILIBRIUM

51. What do we learn form this story?What do we learn form this story? Small number of firms, one firms actions affects the other.Small number of firms, one firms actions affects the other. Where the number of firsm are small we have to think strategically!!Where the number of firsm are small we have to think strategically!! What is the other guy (male or female) up to!What is the other guy (male or female) up to! How will they react to my actionsHow will they react to my actions Will see more stories later.Will see more stories later.

52. Note:Note: Firms wouldn’t go through this tortuous process, they would more likely figure out the situation pretty quickly and if firm 1 couldn’t stop 2 entering they would go to final equilibrium pretty quickly.Firms wouldn’t go through this tortuous process, they would more likely figure out the situation pretty quickly and if firm 1 couldn’t stop 2 entering they would go to final equilibrium pretty quickly. Called Cournot CompetitionCalled Cournot Competition Competing over market share – QuantitiesCompeting over market share – Quantities Can also model price competition- BertrandCan also model price competition- Bertrand

53. Comparison of Cournot with Perfect Compt. and Monopoly Under Monopoly Firm 1 with a linear demand curve Zero MC supplied half the market, that is Q 1 =100=1/2of 200.Under Monopoly Firm 1 with a linear demand curve Zero MC supplied half the market, that is Q 1 =100=1/2of 200. Here with 2 firms each supply 1/3 of 200, that is, 66.66 and total output = 133.33Here with 2 firms each supply 1/3 of 200, that is, 66.66 and total output = 133.33 Under perfect competition MC = 0 would produce at Q = 200Under perfect competition MC = 0 would produce at Q = 200 So oligopoly moving you closer to Perfect competition compared with monopolySo oligopoly moving you closer to Perfect competition compared with monopoly

54. Cournot: 1 firm supply ½ of market1 firm supply ½ of market 2 firms supply 1/3 market each, 2/3 overall.2 firms supply 1/3 market each, 2/3 overall. What about 3 firms?What about 3 firms? 3 firms supply 1/4 market each, 3/4 overall.3 firms supply 1/4 market each, 3/4 overall...and 4 firms?..and 4 firms? 4 firms supply 1/5 market each, 4/5 overall.4 firms supply 1/5 market each, 4/5 overall. N firms, supply 1/(n+1) of market each, n/(n+1) overallN firms, supply 1/(n+1) of market each, n/(n+1) overall So more firms getting closer and closer to perfect competitionSo more firms getting closer and closer to perfect competition

55. Reading:Reading: Lipsey and Chrystal: Positive EconomicsLipsey and Chrystal: Positive Economics –Ch 14 Appendix p274-277 8th Edition

56. £ O Q D 200 MR 1 = MR 2 100 MC P=100 133.3 66.66 133.33 Profits Under Cournot P= 200-2(66.66)= P= 200-133.33= 66.66 Industry Profits=2(TR-TC) =2{66.66(66.66)}=8887.7 But under Monopoly p=100; Q=100 and Profits = 100.100 =10,000 D 1 =D 2

57. £ O Q D 200 MR 1 = MR 2 100 MC P=100 133.3 66.66 133.33 So two firms would be better off if they could get together and agree to limit market: Collusion D 1 =D 2 Profits Under Cournot = 8887.7 Profits under =10,000

58. OLIGOPOLY Key features of oligopolyKey features of oligopoly –barriers to entry –interdependence of firms~What’s s/he up to? –incentives to compete versus incentives to collude Factors favouring collusionFactors favouring collusion Collusive oligopoly: cartelsCollusive oligopoly: cartels –equilibrium of the industry

59. OLIGOPOLY Key features of oligopolyKey features of oligopoly –barriers to entry –interdependence of firms –incentives to compete versus incentives to collude Factors favouring collusionFactors favouring collusion Collusive oligopoly: cartelsCollusive oligopoly: cartels –equilibrium of the industry –allocating and enforcing quotas