What it means
In a competitive market, many sellers offer similar products and prices are driven down towards cost. A monopolist faces no such pressure and is a price maker, meaning it chooses a price and accepts the volume of sales that follows.
To maximise profit, the monopolist produces where marginal revenue (the extra income from selling one more unit) equals marginal cost (the extra cost of making it). Because it must usually lower the price on all units to sell more, marginal revenue falls below the price, so the monopolist sells fewer units at a higher price than a competitive market would.
Monopolies arise in several ways. They can come from natural advantages such as huge fixed costs that make it efficient for one firm to serve the market, from legal protection such as patents, from control of a key resource or from aggressive business practices.
The effects on customers and the economy are usually negative if left unchecked: higher prices, lower output and weaker incentives to innovate. Monopolists can also bring benefits, such as economies of scale and funds for research, which is why policy treats each case on its merits.
Governments respond with competition law, regulation of prices and, for natural monopolies such as water networks, public ownership or price controls. A firm with a very high market share is often scrutinised even if it has not done anything wrong, and mergers that would create a dominant seller can be blocked.
For managers, the lessons run both ways. A business facing a monopolist supplier has little bargaining power and should look for alternatives, while a business approaching a dominant position must expect closer attention from regulators.
In practice
Real-world examples.
Example
A pharmaceutical company holds the only patent on a treatment for a rare condition. It can set the price well above its production cost until the patent expires or a rival product arrives. Health systems negotiate hard, but they have few alternatives.
Example
A town has one water utility that owns all pipes. Because duplicating the network would be wasteful, the regulator sets limits on how much the utility can raise prices. In return the utility is guaranteed a fair return on its investment.
Example
A software firm controls the only widely used platform for an industry. Competition authorities examine whether it is using its position to lock out smaller rivals. The firm argues that customers choose it because it is the best product.
Formula
Calculation
Lerner index = (Price - Marginal cost) / Price
A monopolist sells a patented device at $50 and the marginal cost of producing one more unit is $30. The Lerner index is ($50 - $30) / $50 = $20 / $50 = 0.40, meaning 40% of the price is mark-up above cost. In a competitive market the price would be close to $30 and the index near zero. If the monopolist sells 10,000 units a year, the mark-up above marginal cost brings in $20 x 10,000 = $200,000 a year in contribution before fixed costs.Case study
Seen in the real world.
Ironbridge Rail is an illustrative, fictional company that owns the only rail line to a mining region. Mine operators have no practical alternative to ship their ore in bulk.
For years Ironbridge charged rates that gave it a margin of 45%, far above the sector norm, while service deteriorated. The mine operators complained to the regulator, which investigated and capped the freight rate at a level that allowed a fair return of 12% on the railway's capital.
In this fictional story, the cap lowered shipping costs by 20%, and two of the mines were able to reopen. The fictional railway protested at first but found that higher volumes partly offset the lower price.
Watch out
Common mistakes.
- Assuming a monopolist can charge any price it likes, when demand falls as the price rises.
- Equating a large market share with illegal behaviour, when what matters is how the position was gained and used.
- Forgetting that substitutes can limit a monopolist's power, even if no identical product exists, because customers may switch to something similar if the price is too high.
Questions
People also ask.
What is the difference between a monopolist and a monopoly?
A monopolist is the single seller, while a monopoly is the market situation. People often use the words loosely.
Is being a monopolist illegal?
Usually not by itself, but abusing a dominant position or blocking competition may be. The rules differ by country, so a firm with a high market share should take legal advice before changing prices or contracts.
How does a monopolist set its price?
It picks the output where marginal revenue equals marginal cost and charges the price that customers will pay for that quantity. That price is above marginal cost, which is why monopoly outcomes are criticised as inefficient.
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