1. Principles of Marketing
Perfect Competition
Microeconomics
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What is Marketing?
Principles of Marketing

2. Perfect Competition many firms produce identical products
many buyers are available to buy the product, and many sellers are available to sell the product
sellers and buyers have all relevant information to make rational decisions about the product being bought and sold
firms can enter and leave the market without any restrictions—in other words, there is free entry and exit into and out of the market
Tomato Collage. Farmer’s Market by Andre Natta, CC-BY. Firey Tomatoes by Swaminathan, CC-BY. NorthCharleston Farmer’s Market by NorthCharleston, CC-BY-SA. What’s Better than Love CC torbakhopper, CC-BY.

3. Price Taker
A perfectly competitive firm is known as a price taker, because the pressure of competing firms forces them to accept the prevailing equilibrium price in the market

4. Short-run and Long-run
A short-run production period is when firms are producing with some fixed inputs
Long-run equilibrium in a perfectly competitive industry occurs after all firms have entered and exited the industry and seller profits are driven to zero

5. Supply and Demand
The central characteristic of the model of perfect competition is the fact that price is determined by the interaction of demand and supply; buyers and sellers are price takers.
The model of perfect competition underlies the model of demand and supply.

6. Industry vs. Firms
An industry is made up of firms selling similar products. In perfect competition there are many firms in an industry

7. Supply and Demand for a Perfectly Competitive Industry
Principles of Microeconomics Section 9.2 . Authored by: Anonymous. Located at:  BY-NC-SA: Attribution-NonCommercial-ShareAlike
Perfect competiton: Demand curve for individual producer. Authored by: lostmy1. Provided by: University of South Africa. Located at:  BY: Attribution
Perfect competition: Average revenue = marginal revenue = price. Authored by: lostmy1. Provided by: University of South Africa. Located at:  BY: Attribution

8. Total Revenue, Marginal Revenue, and Average Revenue
Principles of Microeconomics Section 9.2 . Authored by: Anonymous. Located at:  BY-NC-SA: Attribution-NonCommercial-ShareAlike
Perfect competiton: Demand curve for individual producer. Authored by: lostmy1. Provided by: University of South Africa. Located at:  BY: Attribution
Perfect competition: Average revenue = marginal revenue = price. Authored by: lostmy1. Provided by: University of South Africa. Located at:  BY: Attribution

9. Demand Curve for a Perfectly Competitive Firm
Principles of Microeconomics Section 9.2 . Authored by: Anonymous. Located at:  BY-NC-SA: Attribution-NonCommercial-ShareAlike
Perfect competiton: Demand curve for individual producer. Authored by: lostmy1. Provided by: University of South Africa. Located at:  BY: Attribution
Perfect competition: Average revenue = marginal revenue = price. Authored by: lostmy1. Provided by: University of South Africa. Located at:  BY: Attribution

10. Practice Question
In terms of elasticity, how would you describe the demand curve for a single firm in a perfectly competitive market?
Perfectly elastic. Note the horizontal demand line.

11. Total, Average, and Marginal Revenue and Price
Total Revenue equals price times quantity TR = P x Q Average revenue equals marginal revenue, which equals price in a perfectly competitive market MR=P=AR

12. Output decisions
A perfectly competitive firm has only one major decision to make—namely, what quantity to produce. To understand why this is so, consider a different way of writing out the basic definition of profit:
Profit
= Total Revenue – Total Cost
= (Price)(Quantity Produced) – (Average Cost)(Quantity Produced)

13. Total Cost and Total Revenue
Principles of Microeconomics Chapter 8.2. Authored by: OpenStax College. Located BY: Attribution. License Terms: Download for free at
Perfect competition: Point of profit maximisation. Authored by: lostmy1. Provided by: University of South Africa. Located at:  BY: Attribution

14. Marginal Revenue and Cost Formulas
Principles of Microeconomics Chapter 8.2. Authored by: OpenStax College. Located BY: Attribution. License Terms: Download for free at
Perfect competition: Point of profit maximisation. Authored by: lostmy1. Provided by: University of South Africa. Located at:  BY: Attribution

15. Marginal Revenue and Cost
Principles of Microeconomics Chapter 8.2. Authored by: OpenStax College. Located BY: Attribution. License Terms: Download for free at
Perfect competition: Point of profit maximisation. Authored by: lostmy1. Provided by: University of South Africa. Located at:  BY: Attribution

16. Equilibrium
Principles of Microeconomics Chapter 8.2. Authored by: OpenStax College. Located BY: Attribution. License Terms: Download for free at
Perfect competition: Point of profit maximisation. Authored by: lostmy1. Provided by: University of South Africa. Located at:  BY: Attribution
Marginal Revenues and Marginal Costs at the Raspberry Farm: Raspberry Market. The equilibrium price of raspberries is determined through the interaction of market supply and market demand at $4.00.

17. Profit
Price and Average Cost at the Raspberry Farm In (a), price intersects marginal cost above the average cost curve. Since price is greater than average cost, the firm is making a profit
Principles of Microeconomics Chapter 8.2. Authored by: OpenStax College. Provided by: Rice University. Located BY: Attribution. License Terms: Download for free at

18. Break-even
In (b), price intersects marginal cost at the minimum point of the average cost curve. Since price is equal to average cost, the firm is breaking even
Principles of Microeconomics Chapter 8.2. Authored by: OpenStax College. Provided by: Rice University. Located BY: Attribution. License Terms: Download for free at

19. Loss
In (c), price intersects marginal cost below the average cost curve. Since price is less than average cost, the firm is making a loss
Principles of Microeconomics Chapter 8.2. Authored by: OpenStax College. Provided by: Rice University. Located BY: Attribution. License Terms: Download for free at

20. Profit and Loss If… Then… Price > ATC Firm earns an economic profit
Firm earns zero economic profit
Price < ATC
Firm earns a loss
Principles of Microeconomics Chapter 8.2. Authored by: OpenStax College. Provided by: Rice University. Located BY: Attribution. License Terms: Download for free at

21. When should a firm shut down?
price < minimum average variable cost, then firm shuts down
price = minimum average variable cost, then firm stays in business
shutdown point: level of output where the marginal cost curve intersects the average variable cost curve at the minimum point of AVC; if the price is below this point, the firm should shut down immediately

22. Profit, Loss, Shutdown Point
Principles of Microeconomics Chapter 8.2. Authored by: OpenStax College. Located BY: Attribution. License Terms: Download for free at

23. Entry and Exit
Entry: the long-run process of firms entering an industry in response to industry profits
Exit: the long-run process of firms reducing production and shutting down in response to industry losses
Many firms entering or exiting the market will affect overall supply in the market. In turn, a shift in supply for the market as a whole will affect the market price. Entry and exit to and from the market, in the long run, pushes the price down to minimum average total costs so that all firms are earning a zero profit

24. Long-run Equilibrium
Long-run equilibrium: where all firms earn zero economic profits producing the output level where P = MR = MC and P = AC

25. Adjustment Process in Different Types of Industries

26. Efficiency
Long-run equilibrium in perfectly competitive markets meets two important conditions: allocative efficiency and productive efficiency. These two conditions have important implications. First, resources are allocated to their best alternative use. Second, they provide the maximum satisfaction attainable by society.

27. Quick Review What are the characteristics of Perfect Competition?
What is the difference between the firm and the industry?
How do economists calculate and graph the firm’s fixed, variable, average, marginal and total costs?
How do economists measure variable and total costs as the area under the average variable and average total cost curves?
What are the break-even, and the shutdown points of production for a perfectly competitive firm?
What is the difference between short run and long run equilibrium?
Why are perfectly competitive markets efficient?