Perfect competition means every firm ends up earning zero economic profit
Economists' ideal market has countless tiny sellers offering identical goods to perfectly informed buyers. It is almost never seen in reality, and its logical endpoint is striking: in the long run, no firm makes any economic profit at all. Real markets make money precisely because they fall short of that ideal.
Competition, in the economist's sense, is rivalry among firms using price, product, promotion and place to win limited customers. Classical thinkers credited it with driving new products and technologies, widening choice and pushing prices below what a single seller or a small club of sellers would charge. How fierce it is depends on how many firms there are, how hard newcomers find it to enter, what participants know, and who can reach key resources; one simple gauge is how small a share of output the biggest firm holds. The word competitiveness comes from the Latin competere.
The 19th-century economist Antoine Augustin Cournot defined competition as the state in which a firm's price does not change with the quantity it sells, meaning it faces a flat demand curve. His model shows that as the number of firms grows toward infinity, the gap between price and marginal cost shrinks to nothing. Neoclassical perfect competition adds more conditions: identical products, price-taking firms, perfectly mobile resources and costless entry and exit.
Real markets are imperfect. Buyers lack full information, products differ, and barriers protect incumbents, letting firms influence prices and earn profits. At one extreme sits monopoly, a single seller that sets its own price; a natural monopoly arises where huge start-up costs or economies of scale make one supplier cheapest. Oligopolies of a few firms may collude openly or tacitly to fix prices or form cartels, which is why governments regulate them closely. Major American airlines illustrate a market dominated by a handful of rivals.
Between the poles lies monopolistic competition, typical of restaurants, hair salons, clothing and electronics. Many firms sell similar but not identical products, entry is easy, and each has slight pricing power, so they advertise heavily to stand out; short-run profits drift toward zero over time. Geography matters too: research by Easterly and Levine in 2002 found capital, labour and talent cluster in particular places, where networks of suppliers and even rivals create advantages markets alone cannot supply.
Source: Competition (economics)
