ECO-101 Micro Economic Lecture 1

1. MONOPOLY
Micro Lecture

2. MONOPOLY
While a competitive firm is a
price taker, a monopoly firm is
a price maker.

3. Monopoly
A firm is considered a monopoly if . . .
it is the sole seller of its product.
its product does not have close
substitutes.

4. WHY MONOPOLIES ARISE
The fundamental cause of
monopoly is barriers to entry.

5. Why Monopolies Arise
Barriers to entry have three sources:
 Ownership of a key resource.
 This tends to be rare. De Beers is an example
 The government gives a single firm the exclusive
right to produce some good.
 Patents, Copyrights and Government Licensing.
 Costs of production make a single producer more
efficient than a large number of producers.
 Natural Monopolies

6. Economies of Scale as a Cause of
Monopoly...
Average
total cost
Quantity of Output
Cost
0

7. Monopoly versus Competition
Monopoly
 Is the sole producer
 Has a downward-
sloping demand curve
 Is a price maker
 Reduces price to
increase sales
Competitive Firm
Is one of many
producers
Has a horizontal
demand curve
Is a price taker
Sells as much or as
little at same price

8. Quantity of
Output
Demand
(a) A Competitive Firm’s
Demand Curve
(b) A Monopolist’s
Demand Curve
0
Price
0 Quantity of
Output
Price
Demand
Demand Curves for Competitive and
Monopoly Firms...

9. A Monopoly’s Revenue
 Total Revenue
P x Q = TR
 Average Revenue
TR/Q = AR = P
 Marginal Revenue
DTR/DQ = MR

10. A Monopoly’s Marginal
Revenue
 A monopolist’s marginal revenue is
always less than the price of its good.
The demand curve is downward sloping.
When a monopoly drops the price to sell
one more unit, the revenue received from
previously sold units also decreases.

11. A Monopoly’s Total, Average, and Marginal
Revenue
Quantity
(Q)
Price
(P)
Total Revenue
(TR=PxQ)
Average
Revenue
(AR=TR/Q)
Marginal Revenue
(MR= )
0 $11.00 $0.00
1 $10.00 $10.00 $10.00 $10.00
2 $9.00 $18.00 $9.00 $8.00
3 $8.00 $24.00 $8.00 $6.00
4 $7.00 $28.00 $7.00 $4.00
5 $6.00 $30.00 $6.00 $2.00
6 $5.00 $30.00 $5.00 $0.00
7 $4.00 $28.00 $4.00 -$2.00
8 $3.00 $24.00 $3.00 -$4.00
QTR DD /

12. A Monopoly’s Marginal
Revenue
 When a monopoly increases the
amount it sells, it has two effects on
total revenue (P x Q).
The output effect—more output is sold, so
Q is higher.
The price effect—price falls, so P is lower.

13. Demand and Marginal Revenue Curves for a
Monopoly...
Quantity of Water
Price
$11
10
9
8
7
6
5
4
3
2
1
0
-1
-2
-3
-4
1 2 3 4 5 6 7 8
Marginal
revenue
Demand
(average revenue)
Harcourt, Inc. items and derived items copyright © 2001 by Harcourt, Inc.

14. Profit-Maximization for a Monopoly...
Monopoly
price
QuantityQMAX0
Costs and
Revenue
Demand
Average total cost
Marginal revenue
Marginal
cost
A
1. The intersection of
the marginal-revenue
curve and the marginal-
cost curve determines
the profit-maximizing
quantity...
B
2. ...and then the demand
curve shows the price
consistent with this
quantity.
Harcourt, Inc. items and derived items copyright © 2001 by Harcourt, Inc.

15. Comparing Monopoly and Competition
 For a competitive firm, price equals marginal
cost.
P = MR = MC
 For a monopoly firm, price exceeds marginal
cost.
P > MR = MC

16. A Monopoly’s Profit
 Profit equals total revenue minus total costs.
 Profit = TR - TC
 Profit = (TR/Q - TC/Q) x Q
 Profit = (P - ATC) x Q

17. The Monopolist’s Profit...
Quantity0
Costs and
Revenue
Demand
Marginal cost
Marginal revenue
QMAX
BMonopoly
price
E
Average
total cost D
Average total cost
C
Harcourt, Inc. items and derived items copyright © 2001 by Harcourt, Inc.

18. THE MONOPOLIST’S
PROFIT
The monopolist will receive
economic profits as long as price
is greater than average total cost.

19. Public Policy Toward Monopolies
Government responds to the problem of
monopoly in one of four ways.
 Making monopolized industries more
competitive.
 Regulating the behavior of monopolies.
 Turning some private monopolies into public
enterprises.
 Doing nothing at all.

20. Two Important
Antitrust Laws
 Sherman Antitrust Act (1890)
 Reduced the market power of the large and
powerful “trusts” of that time period.
 Clayton Act (1914)
 Strengthened the government’s powers and
authorized private lawsuits.

21. Marginal-Cost Pricing for a Natural
Monopoly...
Regulated
price
Quantity0
Loss
Price
Demand
Marginal cost
Average total cost
Average
total cost

22. PRICE DISCRIMINATION
Price discrimination is the practice of selling
the same good at different prices to different
customers, even though the costs for
producing for the two customers are the
same. In order to do this, the firm must have
market power.

23. Price Discrimination
 Two important effects of price discrimination:
 It can increase the monopolist’s profits.
 It can reduce deadweight loss.
 But in order to price discriminate, the firm must
 Be able to separate the customers on the basis of willingness to
pay.
 Prevent the customers from reselling the product.