Number of Firms: Many: By "many" firms we mean that there are so many firms in the industry that no single firm entering or exiting the industry can shift the supply curve, and therefore, affect market price. Another way of thinking about this concept is to realize that since there are so many firms, no firm has to worry about the actions of a single competitor.; There is no specific number of firms that satisfies this requirement. Some sectors of the agricultural industry might well fit. Most likely, if a single wheat farmer goes out of business, the drop in supply of wheat will be too small to affect the market price of wheat (a commodity that is traded world wide). In a large city the same might be true of restaurants, auto mechanics, dry cleaners, bars, etc.