MonopolyApril 8, 2013
Announcements• Problem Set 1 is due! Pass to end of aisle.• Thanks for clicking to ``follow’’ class website!  (now 90 are ...
Last Class• Studied how marginal revenue and marginal  cost are calculated in simple examples.• We will apply this basic k...
Learning Goals for Today• List the sources of market power that make a  firm a monopoly.  – We will study how monopolies g...
What is a perfectly competitive                market?• Firms have no influence over what the going  price in the market i...
What is individual firm demand under         perfect competition?         N firms     P   (Whole Market)           P   One...
Geometry of Profits• Individual firm profits:   – ∏=PDQ*-TC(Q*)   – ATC=TC/Q* implies ∏=(PD-ATC)Q*.• Recall: Why does MC i...
Putting it together: perfect competition.• Individual profits must be zero.• If profits were negative, firms would shut do...
Why does firm entry squeeze out profits?A. An entering firm can steal all unmet demand.B. An entering firm causes quantity...
Answer: B• Assume profits (red rectangle) are positive and the market quantity is is  NQ*.• If another firm enters market,...
Market Power• Another interpretation of ``price takers’’ is  that they have no market power.• Conversely, but equivalently...
Some sources of market power1   Exclusive control of inputs.2   Patents and copyrights.3   Government licenses.4   Network...
Fifth type: Natural monopolies• Average production cost falls as output  increases• One source: Economies of scale• Anothe...
High Fixed Costs• FC = fixed cost (start-up cost)• MC=marginal cost (assume constant: Example is one  more unit takes one ...
High Fixed Costs Due to R&D• Approximate cost of building a state-of-the-art manufacturing  plant for microprocessors in A...
Recall what a perfectly competitive               market is• Characteristic of perfectly competitive  markets:  – All firm...
The Essential Difference Between Perfectly and        Imperfectly Competitive FirmsP                               P      ...
Under perfect competition, P* is the  market price. What price would aprofit-maximizing firm charge if there were no compe...
Deciding Quantity• Q=8, P=4,                       $  MC=3, MR=0                      8  MC>MR, decrease Q               7...
Deciding Price                                 $• Q=6, P=5                        8  MC=2=MR, optimal Q              7    ...
Again: Under perfect competition, P*is the market price. What price would   a profit-maximizing firm charge if  there were...
The Invisible Hand Fails P       The socially optimal      amount occurs where            MC = MB         S=MCPM          ...
Causes DWL                               DWL          PCS     PS                           D                   MR         ...
Which Monopoly should shut down?                  A                                B$                                 $8  ...
Answer: A. Recall: Profits=(P-                   ATC)Q                 A: LOSS                           B: PROFIT$       ...
Summary: Comparing Monopoly   and Perfect Competition    Monopoly     Perfect Competition    MC = MR           MC = MR    ...
Price Discrimination• Price discrimination: the practice of charging different buyers  different prices for essentially th...
Output With and Without Price           DiscriminationP                                   P          CS                   ...
Example• Rebates: The assumption is that people with high reservation  prices are wealthy and that the opportunity cost of...
What type of monopoly is Verizon /      what is the source of its market                  power?1    Exclusive control of ...
Which of the following is price      discrimination in this case?A. GoodB. BadC. Can’t Say
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040813

  1. 1. MonopolyApril 8, 2013
  2. 2. Announcements• Problem Set 1 is due! Pass to end of aisle.• Thanks for clicking to ``follow’’ class website! (now 90 are signed up.)• Thanks for registering your clickers! Now ____ people are really cool.• Today is the beginning of our discussion of imperfections. (New material for nearly everyone.)
  3. 3. Last Class• Studied how marginal revenue and marginal cost are calculated in simple examples.• We will apply this basic knowledge to study how monopolies profit-maximize.
  4. 4. Learning Goals for Today• List the sources of market power that make a firm a monopoly. – We will study how monopolies gain special privilege in the market place, and what this means.• Show how a given monopoly will behave in the market place – Use marginal revenue and marginal cost to predict profit-maximizing behavior.
  5. 5. What is a perfectly competitive market?• Firms have no influence over what the going price in the market is. – ``Price-takers.’’• Characteristic of perfectly competitive markets: – All firms sell the same (really the same!) product. – There are many buyers and sellers. – There are no costly barriers to starting a business. – Both consumers and firms are well-informed.
  6. 6. What is individual firm demand under perfect competition? N firms P (Whole Market) P One Firm Demand S=MC S=MC P* D D NQ* Q* Q Q
  7. 7. Geometry of Profits• Individual firm profits: – ∏=PDQ*-TC(Q*) – ATC=TC/Q* implies ∏=(PD-ATC)Q*.• Recall: Why does MC intersect ATC at its trough? P One Firm Profit ATC S=MC PD Q* Q
  8. 8. Putting it together: perfect competition.• Individual profits must be zero.• If profits were negative, firms would shut down.• If profits were positive, more firms would enter marketP N firms P One Firm Demand P One Firm Profit ATC S=MC S=MC S=MC D D NQ* Q* Q* Q Q Q
  9. 9. Why does firm entry squeeze out profits?A. An entering firm can steal all unmet demand.B. An entering firm causes quantity sold by each original firm to decrease.
  10. 10. Answer: B• Assume profits (red rectangle) are positive and the market quantity is is NQ*.• If another firm enters market, NQ* quantity now shared amongst N+1 firms.• In this case, Q* being produced by each firm reduces to N(N+1)Q* being produced by each firm, so red rectangle gets smaller. P One Firm Profit ATC S=MC PD Q N/(N+1)Q* Q*
  11. 11. Market Power• Another interpretation of ``price takers’’ is that they have no market power.• Conversely, but equivalently, market power is the ability of an individual firm to set the going price in the market place.• What are some sources of market power?
  12. 12. Some sources of market power1 Exclusive control of inputs.2 Patents and copyrights.3 Government licenses.4 Network economies. When market power allows one firm to take over the market, that firm is called a monopoly.
  13. 13. Fifth type: Natural monopolies• Average production cost falls as output increases• One source: Economies of scale• Another source: High fixed costs
  14. 14. High Fixed Costs• FC = fixed cost (start-up cost)• MC=marginal cost (assume constant: Example is one more unit takes one more laborer which costs one more wage)• TC=FC + VC• ATC=FC/Q + VC/Q where VC/Q=MC ATC=FC/Q+MC MC Q
  15. 15. High Fixed Costs Due to R&D• Approximate cost of building a state-of-the-art manufacturing plant for microprocessors in Asia: $3 billion.• Average cost of bringing a new drug to market: $1.3 billion.• Annual R&D expenditures – Google: 5.2 billion – Microsoft: 9.4 billion – Apple: 2.6 billion – Pfizer: 8.4 billion
  16. 16. Recall what a perfectly competitive market is• Characteristic of perfectly competitive markets: – All firms sell the same (really the same!) product. – There are many buyers and sellers. – There are no costly barriers to starting a business. – Both consumers and firms are well-informed.• Which do monopolies contradict?
  17. 17. The Essential Difference Between Perfectly and Imperfectly Competitive FirmsP P D D Q Q Perfectly Competitive Imperfectly Competitive Firm Firm
  18. 18. Under perfect competition, P* is the market price. What price would aprofit-maximizing firm charge if there were no competition, ie, one firm? PA. PA PA MCB. PB PBC. PC P*D. PD(=0) PCE. P* PD PD Q* Q MR
  19. 19. Deciding Quantity• Q=8, P=4, $ MC=3, MR=0 8 MC>MR, decrease Q 7 MC 6 5• Q=4, P=6 4 MC=1.5, MR=4 3 MC<MR, increase Q 2 1 D• Q=6, P=5 2 4 6 8 10 12 14 16 MC=2=MR, optimal Q MR Q determined by setting MC=MR
  20. 20. Deciding Price $• Q=6, P=5 8 MC=2=MR, optimal Q 7 MC Q determined by setting MC=MR 6 5• Don’t charge $2! Trace up to 4 demand curve; consumers willing 3 to pay $5 when Q=6, so charge 2 them that. 1 D 2 4 6 8 10 12 14 16 MR
  21. 21. Again: Under perfect competition, P*is the market price. What price would a profit-maximizing firm charge if there were no competition, ie, one P firm?A. PA PA MCB. PB PBC. PC P*D. PD(=0) PCE. P* PD PD Q* Q MR
  22. 22. The Invisible Hand Fails P The socially optimal amount occurs where MC = MB S=MCPM The monopolists optimal amount occurs where MC = MR D QM MR Q 22
  23. 23. Causes DWL DWL PCS PS D MR Q 23
  24. 24. Which Monopoly should shut down? A B$ $8 87 ATC 7 MC MC6 6 5 ATC54 43 32 2 D 1 D1 2 4 6 8 10 12 14 16 2 4 6 8 10 12 14 16 MR MR 24
  25. 25. Answer: A. Recall: Profits=(P- ATC)Q A: LOSS B: PROFIT$ $8 87 ATC 7 MC MC6 6 5 ATC54 43 32 2 D 1 D1 2 4 6 8 10 12 14 16 2 4 6 8 10 12 14 16 MR MR 25
  26. 26. Summary: Comparing Monopoly and Perfect Competition Monopoly Perfect Competition MC = MR MC = MR P >MR P = MR P > MC P = MC Deadweight No Deadweight Loss Loss 26
  27. 27. Price Discrimination• Price discrimination: the practice of charging different buyers different prices for essentially the same good.• How does price discrimination affect output and profits?• Simple model – Assume fixed costs=0 and that marginal costs are constant. – Implies that marginal costs equal average costs – Example: If marginal cost=5, then if Q=5, TC=25 and ATC (=TC/Q)=5.
  28. 28. Output With and Without Price DiscriminationP P CS DWL PS MC=ATC MC=ATC MR D D Q Q Can charge each Perfectly Price buyer exactly Single-Price Monopolist Discriminating Monopolist his or her reservation price.
  29. 29. Example• Rebates: The assumption is that people with high reservation prices are wealthy and that the opportunity cost of their time is too high to be bothered to fill out the paperwork to get the rebate.
  30. 30. What type of monopoly is Verizon / what is the source of its market power?1 Exclusive control of inputs.2 Patents and copyrights.3 Government licenses.4 Network economies.A. Natural monopoly.
  31. 31. Which of the following is price discrimination in this case?A. GoodB. BadC. Can’t Say

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