A. Patterns of Imperfect Competition
- Most market structures today fall somewhere on a spectrum between perfect competition and pure monopoly. Under imperfect competition, a firm has some control over its price, a fact seen as a downward-sloping demand curve for the firm's output.
- Important kinds of market structures are (a) monopoly, where a single firm produces all the output in a given industry; (b) oligopoly, where a few sellers of a similar or differentiated product supply the industry; (c) monopolistic competition, where a large number of small firms supply related but somewhat differentiated products; and (d) perfect competition, where a large number of small firms supply an identical product. In the first three cases, firms in the industry face downward-sloping demand curves.
- Economies of scale, or decreasing average costs, are the major source of imperfect competition. When firms can lower costs by expanding their output, perfect competition is destroyed because a few companies can produce the industry's output most efficiently. When the minimum efficient size of plants is large relative to the national or regional market, cost conditions produce imperfect competition.