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Competitive firms and markets. Introduction. Profit maximization Behavior of a firm in a competitive market: In the short run (SR) In the long run (LR). Profit maximization. π (q) = R(q) – C(q) 2 steps: What is the output level, q*, which maximizes profits (minimises losses) ?

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Presentation Transcript
introduction
Introduction
  • Profit maximization
  • Behavior of a firm in a competitive market:
    • In the short run (SR)
    • In the long run (LR)
profit maximization
Profit maximization

π(q) = R(q) – C(q)

2 steps:

  • What is the output level, q*, which maximizes profits (minimises losses) ?
  • Is the firm better off producing q* or shutting down?
output decision
Output decision

What do you think is the typical shape of a profit curve?

At q*, what is the slope of this curve?

Conclusions?

π

q

q*

the single most important thing
The single MOST important thing

A firm maximizes profits when:

MC = MR

  • If MC < MR, how can the firm increase its profits?
  • What if MC > MR?
perfect competition
Perfect competition
  • A competitive firm is said to be a « price taker »

Explain.

  • A competitive firm faces a demand curve which is perfectly elastic.
conditions for perfect competition
Conditions for perfect competition

Five conditions:

  • Large number of firms and consumers
  • Identical product sold across firms
  • Free entry and exit in the market
  • Perfect information
  • No transaction costs
competition in the short run

firm’s internal structure

market structure

Competition in the short run

MC = MR

Yet, R = p x q

and « price taker »

Hence, profit is max if:

MC = _____

 MR = ____

profit maximization graph
 Shade the area corresponding to the firm’s maximum profit.

Compute the value of this maximum profit?

Profit maximization (graph.)

$

C

R

π

q

q*

$/q

MC

AC

P=8

MR=P

6.5

6

0

q*=280

q

shutdown decision
Shutdown decision

Should a firm shut down if π(q*) < 0 ?

Ex1: At q*, R = $2,000, VC = $1,000 and F = $3,000

Ex2: At q*, R = $500, VC = $1,000 and F = $3,000

Conclusion ?

output decision cont
Output decision (cont.)

A firm should continue to operate in the short run if its revenue covers its variable cost.

Shutdown if: R < VC

shutdown decision1
Shutdown decision

Shutdown if R < VC  P x q < VC

 P < VC / q

Therefore:

Shutdown if P < AVC

shutdown decision graph
Shutdown decision (graph.)

MC

  • If the firm produces q* units, what will be its profit (or its loss)?
  • If the firm shuts down, what will it lose?

AC

$/q

AVC

A

P

B

q

q*

0

three regions
Three regions

p

MC

AC

π > 0

operate

break-even point

AVC

π < 0

shutdown point

shutdown

π < 0

q

0

firm s supply curve
Firm’s supply curve

MC

Draw the firm’s supply curve.

Explain

AC

$/q

AVC

q

market supply curve
Market supply curve

Horizontal sum of individual firms’ supply curves (like D)

Ex: 2 firms, Q = q1 + q2.

p

p

p

s1

s2

S = s1 + s2

q1

q2

Q

100

400

100

300

200

700

price elasticity of supply
Price-elasticity of supply

Similar to the price elasticity of demand:

Interpretation: The price elasticity of supply represents the percentage change in Qs when P changes by 1%.

% change in Qs∆Qs/QsEsp = --------------------------- = ---------------- % change in P ∆P/P

competition in the long run
Competition in the long run

Recall: all costs are variable

  • Profit maximization: MC = MR  MC = P
  • Shutdown decision: R < C,

(selling below cost is not sustainable in the long-run).

Hence, shutdown if R < C  π < 0.

In the LR, a firm only produces if it does not incur any losses

lr firm supply curve
LR firm supply curve

MCLR

Draw.

ACLR

$/q

AVCLR

q

lr market supply curve
LR market supply curve

As before: horizontal sum of individual curves…

BUT… how many firms are there?

  • If the market is profitable (π > 0  p > AC), what will happen?
  • Else, if π < 0 (LR loss), describe the sequence of events.
graphically
Graphically

p

$/q

MCLR

ACLR

SLR

p = min ACLR

q

Q

zero profits in the long run
Zero profits in the long run ???

Recall: We’re talking about economic profit

(π= πaccounting – Copportunity)

π < 0  I could earn more money elsewhere

Hence, when π = 0, the firm « makes money » (πaccounting > 0), but no more than it would if it utilized its resources differently: it is making normal profits.

conclusion
Conclusion
  • Behavior of a competitive firm
  • MC = MR : Reconciling the internal structure of the firm with current market conditions
  • Next: Supply and demand, a cooperative process
example 1
Example (1)

A pizza shop in a perfectly competitive environment with the following total costs produces six pizzas.

Quantity Total Costs ($)

0 10

1 15

2 25

3 40

4 60

5 85

6 115

7 150

What is the price of a a pizza in this industry?

example 11
Example (1)

Perfect competition Firm is a price taker so it sets q such that MC=P

Quantity Total Costs ($) MC

0 10 ---

1 15 5

2 25 10

3 40 15

4 60 20

5 85 25

6 115 30

7 150 35

At q=6, MC=30, the price is 30$

example 2
Example (2)

You operate Econsultants. One of your clients, Handspring, has recently decided to start a cell phone division in addition to producing handheld personal organizers. Unfortunately, this division of the company is not doing as well as they had hoped and has asked you to assess whether or not they should continue to operate in the short run. The current market price for a cell phone is $100/phone and at this price, Handspring would like to supply 100 phones. However, at a quantity of 100 phones, Handspring has an ATC of $110/phone and an AVC of $75/phone. Starting a cell phone division involved many one-time costs (i.e. the building of factories). In the short run, would you suggest that Handspring continue to operate this division of the company? Explain your answer.

example 21
Example (2)

Operate in SR or not? Represent graphically.

P=100$ q=100 ATC=110$ AVC=75$

The question assumes that q is such that P=MC, the firm is optimizeing.

SR decision  is P > than AVC?

Yes  Operate in the short run to eat some of the fixed costs.

example 3
Example (3)

The owner of a firm wants to know if it should change the level of output and/or if it should stay in the business in the short and long run. You are given the following information.

Rev=3,000$ AVC is @ min

FC=500$ TC=3125$ P=40$

example 31
Example (3)

1. Is P=MC?

MC=AVC because it is @ min. We need AVC.

VC=TC-FC  3125$-500$=2625$.

AVC=VC/Q, We need Q.

Rev=P*Q  3,000$=Q*40$

 Q=3,000$/40$=75

AVC=2625$/75$=35$

 P (40$) > AVC (35$)!!!!! This means that the level of output is not chosen optimally. Output needs to be raised before decisions about SR and LR are to be taken.

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