The best slide of managerial economics for you to refer to. Credit to: Dr Mohammed Alwosabi

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CHAPTER NINE
MONOPOLY
This chapter examines how a market controlled by a single producer
behaves. What price will a monopolist charge for his output? How much will
he produce?
The basic characteristics of monopoly market structure are summarized as
follows:
1. A single firm produces the entire market supply of a particular good or
service which has no close substitutes.
2. There are high barriers that prevent other firms from entry. Barriers to
entry are restrictions that make it difficult or impossible for new firms to
enter a particular market. These barriers could be legal or natural.
Examples of legal restrictions include government license, patent,
copyright, etc. Natural monopoly exists when one firm can supply the
entire market at a lower price than any other firm.
3. Since there is only one firm, then the firm is the market (or the industry).
The demand curve facing the monopoly firm is identical to the downward
sloping market demand curve. Thus, monopoly faces a trade off between
price and quantity sold.
4. The monopoly has a market power. Market power is the ability to
influence the market price of a good or service. Monopoly firm is a price
maker.
5. The marginal revenue no longer equals price. MR curve is a down-ward
sloping and lies below demand curve at every point but the first (MR < P).
[Only firms that confront a horizontal demand curve (perfectly competitive
firms) equate marginal cost and price.]
6. A monopoly firm has no absolute market power. It can charge any price
(within the demand curve limits); i.e., can charge the maximum price
people are willing to pay for a given level of output. It is constrained on the
exercise of market power by the demand curve facing it.

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7. How strong a constraint is depends on the price elasticity of demand. The
greater the price elasticity of demand, the less power the monopolist has.
The lower the price elasticity of demand, the more power the monopolist
has
8. Profit-maximizing monopoly produces only in the elastic range of its
demand curve (never produces in the inelastic portion).
9. Like any producer, Monopoly firm will strive to produce its output at the
rate that maximizes total profits. As in perfect competition, monopoly
should expand production as long as MR > MC and produce at that rate of
output where MR = MC.
10. Applying profit-maximizing rule (MR =MC), the following must be true:
1. P > MC, 2. P > MR, 3. P > ATC (to have positive economic profit), 4. P
> AVC
11. A monopoly receives larger profits than a comparable competitive firm by
reducing the quantity supplied and increasing the price.
12. In short run, there may be economic loss (or of course economic profit)
but in long run there will be positive (greater than zero) economic profit.
13. Although monopoly is usually regulated by government, our focus now is
on how monopoly behaves in the absence of regulation. So we can
understand why government must regulate the monopolies
It is assumed, for comparison purposes, that the monopolist is not taking
advantage of economies of scale. Multiple plants are maintained. Therefore,
the same short run MC and AC as in perfect competition. (But this is unlikely
situation because monopolist would like to achieve economies of scale)
Any firm that has economies of scale will
o Make investment decision to increase capacity
o Try to produce in one large plant
o Be able to produce at a lower unit cost as it increases production
o Face a downward sloping LRATC

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Example: From this table, you can see that P > MR except for the first unit.
Example
Based on the above figure,
Because the monopoly firm faces downward sloping demand curve, MR
no longer equal P. MR < P (MR curve < demand curve).
To maximize profits, the monopolist must find the rate of output where MC
= MR (point M).
That rate of output (Qm = 50) can be sold at the monopoly price of Pm = $9
(point X on demand curve). Price is determined by moving directly up from
Q P TR MR
0 14 0
1 13 13 13
2 12 24 11
3 11 33 9
4 10 40 7
5 9 45 5
6 8 48 3
7 7 49 1
8 6 48 -1
Qm=50
YZ
4
Pm = 9
X
Dm
MC
ATC
MR
M
Q
P

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point M to demand curve. i.e., the monopolist price will move upward
along the same demand curve.
As a result of monopoly,
Total profit (for monopoly) = (P – ATC) * Q = (9 - 4) * 50 = $250
(area: XYZPm)
We know that the high economic profits tend to attract other firms to enter
the market.
However, in monopoly, profits are maintained as long as barriers to entry
prevent any competitors from entering the market.
Monopolist has less pressure to reduce costs or improve quality
Example
A monopolist’s demand function is P = 100 -8Q,
and its Total Cost function is TC = 50 +80Q -10Q2
+0.6 Q3
Find
a. The price and output level that maximizes profit
b. The price and output level that maximizes TR
Price Discrimination
One of the result of market power is price discrimination
It refers to the sale of an identical good at different prices to different
consumers by a single seller.
It allows a producer to reap the highest possible average price for the output
which increases TR and profit.
Monopoly would charge higher prices from those who have lower price
elasticity of demand (more price-inelastic demand)
It requires the firm to eliminate possible resale of its product otherwise it is
ineffective. Price discrimination is limited to firms that sell products that
cannot be resold

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Barriers to Entry
Lack of competition gives monopolist the pricing power. To keep this power,
keep the potential competitors out of market. Thus, keep high entry barriers.
The main types of Barriers to Entry are:
1. Patents – offers a producer 20 years of exclusive rights to produce a
particular product.
2. Public Franchises – governments also create and maintain monopolies by
giving a single firm the exclusive right to supply a particular good or
service, although other firms can product it.
3. Control of Key Inputs – A company may prevent competition by securing
exclusive access to key inputs.
4. Lawsuits – May be used to prevent new companies from entering an
industry.
5. Acquisition – When all else fails, purchase a potential competitor.
6. Economies of Scale – A monopoly may persist because of cost
advantages over smaller firms
Contestable Markets
1. Contestable markets are characterized by moderate (low) barriers to entry.
When profit increase to a certain level other firms will enticed to enter the
market.
2. Entry occurs when price increase above ATC, but the LR economic profit is
low
3. Potential competition may come from foreign firms or from a new technology
that may produce new substitutes
4. Last year, CNN generated about $227 million in operating profit. As a
monopolist’s profits grow, would-be competitors will try to overcome barriers
to entry. If entry is possible, a monopolized market may be contestable,