Download - Session 10 firms in competitive markets
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Session10Session10
Firms in Competitive Markets
Lectured by Prof. Dr. Ferdinand D. Saragih, MA
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WHAT IS A COMPETITIVE MARKET?
• A perfectly competitive market has the following characteristics:• There are many buyers and sellers in the market.• The goods offered by the various sellers are largely
the same.• Firms can freely enter or exit the market.
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WHAT IS A COMPETITIVE MARKET?
• As a result of its characteristics, the perfectly competitive market has the following outcomes:• The actions of any single buyer or seller in the
market have a negligible impact on the market price.
• Each buyer and seller takes the market price as given.
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WHAT IS A COMPETITIVE MARKET?
• A competitive market has many buyers and sellers trading identical products so that each buyer and seller is a price taker.• Buyers and sellers must accept the price determined
by the market.
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The Revenue of a Competitive Firm
• Total revenue for a firm is the selling price times the quantity sold.
TR = (P TR = (P Q) Q)
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The Revenue of a Competitive Firm
• Total revenue is proportional to the amount of output.
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The Revenue of a Competitive Firm
• Average revenue tells us how much revenue a firm receives for the typical unit sold.
• Average revenue is total revenue divided by the quantity sold.
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The Revenue of a Competitive Firm
• In perfect competition, average revenue equals the price of the good.
A v erag e R ev en u e =T o ta l rev en u e
Q u an tity
P rice Q u an tity
Q u an tity
P rice
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The Revenue of a Competitive Firm
• Marginal revenue is the change in total revenue from an additional unit sold.
MR =MR =TR/ TR/ QQ
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The Revenue of a Competitive Firm
• For competitive firms, marginal revenue equals the price of the good.
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Table 1 Total, Average, and Marginal Revenue for a Competitive Firm
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PROFIT MAXIMIZATION AND THE COMPETITIVE FIRM’S SUPPLY CURVE
• The goal of a competitive firm is to maximize profit.
• This means that the firm will want to produce the quantity that maximizes the difference between total revenue and total cost.
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Table 2 Profit Maximization: A Numerical Example
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Figure 1 Profit Maximization for a Competitive Firm
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Quantity0
Costsand
Revenue
MC
ATC
AVC
MC1
Q1
MC2
Q2
The firm maximizesprofit by producing the quantity at whichmarginal cost equalsmarginal revenue.
QMAX
P = MR1 = MR2 P = AR = MR
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PROFIT MAXIMIZATION AND THE COMPETITIVE FIRM’S SUPPLY CURVE
• Profit maximization occurs at the quantity where marginal revenue equals marginal cost.
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PROFIT MAXIMIZATION AND THE COMPETITIVE FIRM’S SUPPLY CURVE
• When MR > MC increase Q
• When MR < MC decrease Q
• WhenWhen MR = MC MR = MC Profit is maximizedProfit is maximized..
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Figure 2 Marginal Cost as the Competitive Firm’s Supply Curve
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Quantity0
Price
MC
ATC
AVC
P1
Q1
P2
Q2
This section of thefirm’s MC curve isalso the firm’s supplycurve.
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The Firm’s Short-Run Decision to Shut Down
• A shutdown refers to a short-run decision not to produce anything during a specific period of time because of current market conditions.
• Exit refers to a long-run decision to leave the market.
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The Firm’s Short-Run Decision to Shut Down
• The firm considers its sunk costs when deciding to exit, but ignores them when deciding whether to shut down.• Sunk costs are costs that have already been
committed and cannot be recovered.
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The Firm’s Short-Run Decision to Shut Down
• The firm shuts down if the revenue it gets from producing is less than the variable cost of production.• Shut down if TR < VC• Shut down if TR/Q < VC/Q• Shut down if P < AVC
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Figure 3 The Competitive Firm’s Short Run Supply Curve
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MC
Quantity
ATC
AVC
0
Costs
Firmshutsdown ifP< AVC
Firm’s short-runsupply curve
If P > AVC, firm will continue to produce in the short run.
If P > ATC, the firm will continue to produce at a profit.
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The Firm’s Short-Run Decision to Shut Down
• The portion of the marginal-cost curve that lies above average variable cost is the competitive firm’s short-run supply curve.
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The Firm’s Long-Run Decision to Exit or Enter a Market
• In the long run, the firm exits if the revenue it would get from producing is less than its total cost.• Exit if TR < TC• Exit if TR/Q < TC/Q• Exit if P < ATC
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The Firm’s Long-Run Decision to Exit or Enter a Market
• A firm will enter the industry if such an action would be profitable. • Enter if TR > TC• Enter if TR/Q > TC/Q• Enter if P > ATC
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Figure 4 The Competitive Firm’s Long-Run Supply Curve
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MC = long-run S
Firmexits ifP < ATC
Quantity
ATC
0
CostsFirm’s long-runsupply curve
Firmenters ifP > ATC
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THE SUPPLY CURVE IN A COMPETITIVE MARKET
• The competitive firm’s long-run supply curvelong-run supply curve is the portion of its marginal-cost curve that lies above average total cost.
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Figure 4 The Competitive Firm’s Long-Run Supply Curve
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MC
Quantity
ATC
0
Costs
Firm’s long-runsupply curve
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THE SUPPLY CURVE IN A COMPETITIVE MARKET
• Short-Run Supply Curve• The portion of its marginal cost curve that lies
above average variable cost.
• Long-Run Supply Curve• The marginal cost curve above the minimum point
of its average total cost curve.
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Figure 5 Profit as the Area between Price and Average Total Cost
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(a) A Firm with Profits
Quantity0
Price
P = AR = MR
ATCMC
P
ATC
Q(profit-maximizing quantity)
Profit
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Figure 5 Profit as the Area between Price and Average Total Cost
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(b) A Firm with Losses
Quantity0
Price
ATCMC
(loss-minimizing quantity)
P = AR = MRP
ATC
Q
Loss
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THE SUPPLY CURVE IN A COMPETITIVE MARKET
• Market supply equals the sum of the quantities supplied by the individual firms in the market.
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The Short Run: Market Supply with a Fixed Number of Firms
• For any given price, each firm supplies a quantity of output so that its marginal cost equals price.
• The market supply curve reflects the individual firms’ marginal cost curves.
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Figure 6 Market Supply with a Fixed Number of Firms
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(a) Individual Firm Supply
Quantity (firm)0
Price
MC
1.00
100
$2.00
200
(b) Market Supply
Quantity (market)0
Price
Supply
1.00
100,000
$2.00
200,000
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The Long Run: Market Supply with Entry and Exit
• Firms will enter or exit the market until profit is driven to zero.
• In the long run, price equals the minimum of average total cost.
• The long-run market supply curve is horizontal at this price.
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Figure 7 Market Supply with Entry and Exit
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(a) Firm’s Zero-Profit Condition
Quantity (firm)0
Price
(b) Market Supply
Quantity (market)
Price
0
P = minimumATC
Supply
MC
ATC
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The Long Run: Market Supply with Entry and Exit
• At the end of the process of entry and exit, firms that remain must be making zero economic profit.
• The process of entry and exit ends only when price and average total cost are driven to equality.
• Long-run equilibrium must have firms operating at their efficient scale.
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Why Do Competitive Firms Stay in Business If They Make Zero Profit?
• Profit equals total revenue minus total cost.
• Total cost includes all the opportunity costs of the firm.
• In the zero-profit equilibrium, the firm’s revenue compensates the owners for the time and money they expend to keep the business going.
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A Shift in Demand in the Short Run and Long Run
• An increase in demand raises price and quantity in the short run.
• Firms earn profits because price now exceeds average total cost.
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Figure 8 An Increase in Demand in the Short Run and Long Run
Firm
(a) Initial Condition
Quantity (firm)0
Price
Market
Quantity (market)
Price
0
DDemand, 1
SShort-run supply, 1
P1
ATC
Long-runsupply
P1
1Q
A
MC
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Figure 8 An Increase in Demand in the Short Run and Long Run
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MarketFirm
(b) Short-Run Response
Quantity (firm)0
Price
MC ATCProfit
P1
Quantity (market)
Long-runsupply
Price
0
D1
D2
P1
S1
P2
Q1
A
Q2
P2
B
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Figure 8 An Increase in Demand in the Short Run and Long Run
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P1
Firm
(c) Long-Run Response
Quantity (firm)0
Price
MC ATC
Market
Quantity (market)
Price
0
P1
P2
Q1 Q2
Long-runsupply
B
D1
D2
S1
A
S2
Q3
C
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Why the Long-Run Supply Curve Might Slope Upward
• Some resources used in production may be available only in limited quantities.
• Firms may have different costs.
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Why the Long-Run Supply Curve Might Slope Upward
• Marginal Firm• The marginal firm is the firm that would exit the
market if the price were any lower.
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Summary
• Because a competitive firm is a price taker, its revenue is proportional to the amount of output it produces.
• The price of the good equals both the firm’s average revenue and its marginal revenue.
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Summary
• To maximize profit, a firm chooses the quantity of output such that marginal revenue equals marginal cost.
• This is also the quantity at which price equals marginal cost.
• Therefore, the firm’s marginal cost curve is its supply curve.
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Summary
• In the short run, when a firm cannot recover its fixed costs, the firm will choose to shut down temporarily if the price of the good is less than average variable cost.
• In the long run, when the firm can recover both fixed and variable costs, it will choose to exit if the price is less than average total cost.
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Summary
• In a market with free entry and exit, profits are driven to zero in the long run and all firms produce at the efficient scale.
• Changes in demand have different effects over different time horizons.
• In the long run, the number of firms adjusts to drive the market back to the zero-profit equilibrium.