Market analysis

In a competitive market many firms sell similar products and none can set the price alone. A firm that charges more than its rivals loses customers, so price is pushed down towards the cost of production and firms must keep costs low to survive. Consumers get low prices, wide choice and pressure for quality; firms earn only normal profit in the long run.

A monopoly — one dominant seller protected by barriers to entry — faces no such pressure. It can restrict output to raise price and earn supernormal profit for as long as the barriers hold. Consumers pay more, buy less, and may have little choice; the firm has less incentive to cut costs or improve the product. The classic analysis is therefore: competition → lower price, higher output, more choice; monopoly → higher price, lower output, less choice.

The simple comparison is not the whole story. A monopoly can achieve economies of scale: one firm producing the whole market's output may have far lower average costs than many small firms, and may pass some of the saving on in lower prices. In industries such as water supply, electricity grids and railways, duplicating networks would be wasteful — a natural monopoly — so one supplier is cheaper.

Supernormal profit can also fund research and development that competitive firms cannot afford, and a patent that creates a temporary monopoly is exactly what encourages firms to invent in the first place. Large firms may offer more reliable supply and can compete internationally. Whether these benefits outweigh the higher prices depends on the industry.

Market structure is not fixed. When barriers to entry fall — a patent expires, a new technology makes entry cheap, a government opens an industry to competition — new firms enter, price falls and output rises. When barriers rise — mergers reduce the number of firms, or a firm gains control of a key resource — a market can drift towards monopoly.

Analysing a market therefore means asking what the barriers are and how strong they are. Online platforms, for example, have low costs of entry yet strong barriers from network effects: customers want to be where other customers are. This is why a market can look competitive on the surface and still behave like a monopoly.

Governments respond to monopoly power in several ways. Competition law can block mergers that would create a dominant firm and fine firms that abuse their position by fixing prices or excluding rivals. Regulation can cap the prices a natural monopoly charges or set service standards — common for water and energy. Nationalisation brings a natural monopoly into public ownership so that it can be run in the public interest, while privatisation with regulation tries to combine private efficiency with public protection. Lowering barriers — by ending legal monopolies or opening markets to imports — adds competition directly.

Each response has costs: regulators can be captured or make mistakes, competition investigations are slow, and public ownership weakens cost control. The choice depends on whether the monopoly is natural, whether it is innovating, and how badly consumers are being harmed.