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TRANSCRIPT
Oligopolies and monopolistic competition
In between the two competition benchmarks
Oligopolies and monopolistic competition
Today we finish examining the competition continuum we introduced last week
After today, you will know all four of the main models used to explain the different market structuresThe two extreme benchmarks (previous
weeks)The two “middle ground” models
Oligopolies and monopolistic competition
Market power of firms
Perfect competition
Many firms with a homogeneous product
Oligopoly
A few producers with high market power
Monopoly
A single producer
Monopolistic competition
Many firms with differentiated products
The “competition continuum”
Oligopolies and monopolistic competition
Importantly, the two cases we see today are in the middle of the competition continuum
They are more realistic that the extreme benchmarks of perfect competition and pure monopoly More “powerful” models in that they correspond
better to the real world Unfortunately, this means that they are also
more complex These models have required the development of
new tools
Oligopolies and monopolistic competition
Oligopolies
Monopolistic competition
Oligopolies
The oligopoly corresponds to the following market structure :
1. A few large producers2. Homogeneous products3. No entry of competing producers on the
market4. Perfect information5. Perfect mobility of inputs
Apart from the few producers instead of one, this is not much different from the monopoly
Oligopolies
Oligopolies are usually caused by the presence of barriers to entry which deter potential competitors.
Institutional or regulatory barriers (Example: defence industry or utilities)
The nature of the technology, which determines the existence of returns to scale and the minimal efficient scale of the firm (Example : Aeronautical industry)
Absolute cost differentials: Vertical integration, access to an efficient supply or distribution network (example: agribusiness)
Oligopolies
This is a common situation in many industries : Car industry, aeronautical industry Agribusiness (Nestlé, Danone, Kraft foods, Coca-
Cola Co) Electronics, computing Utilities, buildings, etc.
Compared to the monopoly case, each firm has an extra element to consider: The behaviour of its competitors (introduced last week) Because a firm’s output influences market
prices, competitors will react This will lead to strategic behaviour
Oligopolies
A simple solution for the market price and quantity is possible if the firms decide to cooperate. This cooperative equilibrium is called a cartel.
OPEC is a good example: an organisation of independent producers, producing the same goods, who decide to coordinate their strategies, so as to limit their output and increase prices. The good news: When firms do this (ie maximise
collective profit), they practise monopoly pricing and get monopoly profits. This means the simple monopoly model is enough
The “bad” news: This practise is illegal in most countries! Also, there is an incentive to cheat. So usually, firms will not cooperate, and a more complex model is needed...
Oligopolies
Price
Quantity
mCA ACA
Inverse demand facing firm A
mRA
q
p G
The cooperative equilibrium
Oligopolies
When firms in an oligopoly do not cooperate, there is a non-cooperative equilibrium
Compared to the monopoly and the cooperative cartel case, it becomes difficult to characterise the market equilibrium (equilibrium price and quantity) If a firm changes its output (price), this changes the market
price, and the profits of competitors. They will react to this change in profits by changing their output (price).
The optimal strategy of a firm depends on the strategies of its competitors. There are as many types of equilibria as there are combinations of strategies.
Oligopolies
As a simplification, economic theory typically examines the duopoly: The case with two producers on a market with barriers to entry
There are many possible models of duopoly:
Quantity competition
Price competition
Simultaneous setting
Cournot duopoly
Bertrand duopoly
Leader/Follower setting
Stackelberg duopoly
Price leadership
Oligopolies
The Cournot duopoly (1838) :
Is the first and simplest model of a duopoly: each firm considers the output of its competitor as given
The 2 firms simultaneously choose their output, and consider that the current output of their competitor will not change (not very realistic...)
Oligopolies
The profits of the two firms is given by:
For simplicity, we re-write them as:
1 1 11 1
2
2
2 21 22
q q qq
q q
p
p cq q
c
The cost of production depends only on the firm’s output
The market price however, depends on the aggregate output q1 + q2
1 1
2
2
12
1
2
,
,
q
q
F
F
q
q
Oligopolies
As for all firms, the maximum profit condition is given by the first order condition
These first order conditions can be rearranged to give a system of equations known as reaction functions
0i iq
11
22
1 2
1
2
2 2
1
1
,0
,0
q
q
q
q
q q
qF
q
F
2
2
1
1
1
2
q qf
qfq
A reaction function tells you the quantity q1 that maximises the profits of firm 1 given the quantity q2 produced by firm 2
Oligopolies
q2
q1
C
Reaction function of firm 1
Reaction function of firm 2
q*1
q*2
C0C1
C2
C3
Reaction functions and Cournot equilibrium
1 1 2q f q
2 2 1q f q
Oligopolies
The existence and the stability of an equilibrium in an oligopoly depends on the expectations that firms form about the strategies of their competitors Several different equilibria are possible depending on
the various combinations of strategies formulated. Most often, the tools of classical economics cannot
find these different equilibria... ...unless strong simplifying assumptions are made.
See the Cournot example: “treat output as given” Game theory was developed as a response to this
problem. This will be seen next week
Oligopolies and monopolistic competition
Oligopolies
Monopolistic competition
Monopolistic competition
Monopolistic competition corresponds to the following market structure :
1. Large number of agents (Atomicity) 2. Differentiated products3. Free entry and exit from the market4. Perfect information5. Perfect mobility of inputs
The output of each producer is slightly different from the others ⇒ existence of varieties (brands)
Monopolistic competition
Because each firm produces a slightly different good, consumers can have preferences over these different varieties.
There will be an element of “brand loyalty” in consumer behaviour, where one variety of a good will be preferred over another one.
Examples: Corner shops, restaurants, hair dressers, travel agents, etc.
Unfortunately, the algebra necessary to generate such “preference for variety” models is a bit complicated ⇒ We will only look at the diagrams
Monopolistic competition
Each firm has a small amount of market power Because of “brand loyalty”, it can increase its price
a bit without loosing all its customers (as is the case in perfect competition)
The price elasticity of demand is not infinite The demand curve facing the firm is downward-
sloping (not flat as in perfect competition) There will be a (small) mark-up: Price is above mC
However, because firms can enter the market freely, economic profits are equal to zero in the long run
Monopolistic competition
How does this work ? At the firm level, the short run equilibrium
diagram looks like the monopoly diagram It also solves like a monopoly ⇒ short run profits
The adjustment to the long run behaves like perfect competition: Extra firms enter the market, attracted by the
profits The demand facing each firm decreases until
profits are competed away
Monopolistic competition
mC
AC
Price Price
D
Firm-market equilibrium
Firm level Market level
Quantityquantity
dp
Q
Positive profits in the short run
mR
S
q
Monopolistic competition
mC
AC
Price Price
S
D
Firm-market equilibrium
Firm level Market level
Quantityquantityq Q
zero profits in the long run
dmR
S
Positive profits attract firms to the market (free entry + perfect information)
Q2q2
pp2
Monopolistic competition
Price
Quantityq
p
DemandmR
In the long run, Total revenue is equal to Total cost ⇒ Profits are equal to zero
mC AC
Long run welfare implications
Similar to perfect competition. An improvement on monopolies/oligopolies
p = AC
Monopolistic competition
Price
Quantity
mC AC
q
p
DemandmR
Even in the long run, there is a mark-up
p > mC
This implies some deadweight loss
Consumer surplus
Producer surplus
Long run welfare implications
Monopolistic competition
Price
Quantityq
p
DemandmR
Firms are not producing at the minimum AC. There is excess capacity (i.e. some production resources are wasted)
q*
mC AC
Long run welfare implications
Monopolistic competition
This model has a competitive limit The weaker the preferences of consumer
for variety (the “brand loyalty”), the less market power the firms have and the closer the model predictions are to perfect competition The demand curve becomes flatter The mark-up and deadweight loss are reduced
The equilibrium tends to P = mC = AC
Monopolistic competition
mC
AC
Price Price
The competitive limit
Case 1 Case 2
Quantityquantity
dmR
p
q
mC
AC
dmR
q
p