PART TWO: Producers, Consumers, and Competitive Markets
8 Profit Maximization and Competitive Supply
Summary
Questions for Review
Nội dung
314 PART • Producers, Consumers, and Competitive Markets restricted by local zoning laws Many communities outlaw it entirely, while others limit it to certain areas Because urban land on which most rental housing is located is restricted and valuable, the long-run elasticity of supply of rental housing is much lower than the elasticity of supply of owner-occupied housing As the price of rental-housing services rises, new high-rise rental units are built and older units are renovated—a practice that increases the quantity of rental services With urban land becoming more valuable as housing density increases, and with the cost of construction soaring with the height of buildings, increased demand causes the input costs of rental housing to rise In this increasing-cost case, the elasticity of supply can be much less than 1; in one study, the authors found it to be 0.36.11 SUMMARY Managers can operate in accordance with a complex set of objectives and under various constraints However, we can assume that firms act as if they are maximizing long-run profit Many markets may approximate perfect competition in that one or more firms act as if they face a nearly horizontal demand curve In general, the number of firms in an industry is not always a good indicator of the extent to which that industry is competitive Because a firm in a competitive market accounts for a small share of total industry output, it makes its output choice under the assumption that its production decision will have no effect on the price of the product In this case, the demand curve and the marginal revenue curve are identical In the short run, a competitive firm maximizes its profit by choosing an output at which price is equal to (short-run) marginal cost Price must, however, be greater than or equal to the firm’s minimum average variable cost of production The short-run market supply curve is the horizontal summation of the supply curves of the firms in an industry It can be characterized by the elasticity of supply: the percentage change in quantity supplied in response to a percentage change in price The producer surplus for a firm is the difference between its revenue and the minimum cost that would 10 be necessary to produce the profit-maximizing output In both the short run and the long run, producer surplus is the area under the horizontal price line and above the marginal cost of production Economic rent is the payment for a scarce factor of production less the minimum amount necessary to hire that factor In the long run in a competitive market, producer surplus is equal to the economic rent generated by all scarce factors of production In the long run, profit-maximizing competitive firms choose the output at which price is equal to long-run marginal cost A long-run competitive equilibrium occurs under these conditions: (a) when firms maximize profit; (b) when all firms earn zero economic profit, so that there is no incentive to enter or exit the industry; and (c) when the quantity of the product demanded is equal to the quantity supplied The long-run supply curve for a firm is horizontal when the industry is a constant-cost industry in which the increased demand for inputs to production (associated with an increased demand for the product) has no effect on the market price of the inputs But the longrun supply curve for a firm is upward sloping in an increasing-cost industry, where the increased demand for inputs causes the market price of some or all inputs to rise QUESTIONS FOR REVIEW Why would a firm that incurs losses choose to produce rather than shut down? Explain why the industry supply curve is not the longrun industry marginal cost curve In long-run equilibrium, all firms in the industry earn zero economic profit Why is this true? What is the difference between economic profit and producer surplus? 11 Why firms enter an industry when they know that in the long run economic profit will be zero? At the beginning of the twentieth century, there were many small American automobile manufacturers At the end of the century, there were only three large ones Suppose that this situation is not the result of lax federal enforcement of antimonopoly laws How you explain the decrease in the number of manufacturers? John M Quigley and Stephen S Raphael, “Regulation and the High Cost of Housing in California,” American Economic Review, Vol 95(2), 2005: 323–328