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Cambridge IGCSE 0455 · Unit 3 · Topic 3.7

Types of Markets

Clear, syllabus-mapped Cambridge IGCSE revision notes on types of markets: explanations, worked examples and exam technique, then a free targeted practice drill.

Cambridge IGCSEIGCSE 0455Free revision notes
Contents: 14 sections

Cambridge IGCSE Economics 0455

Syllabus points

What is market structure?

Market structure describes how a market is organised, above all, how many firms there are and how easily new firms can enter.

The two structures IGCSE focuses on sit at opposite ends:

Competitive marketMonopoly
Number of firmsManyOne (or one dominant firm)
Barriers to entryLowHigh
Control over priceVery little: firms are price takersConsiderable: the firm is a price maker
ProductsSimilar or identicalNo close substitutes
Consumer choiceWideLimited
PricesLowerHigher
Profits in the long runNormal, because entry competes them awayAbnormal profit can persist

Barriers to entry

Barriers to entry are what stops new firms joining a market, and they are the reason a monopoly can persist:

Where barriers are low, high profits attract new firms, competition increases and prices fall. Where they are high, that correction never happens.

Effects of competition

Real-world case · 3 minWhy rival airlines match each other on priceWendover ProductionsRival carriers converge on the same fare on a shared route, and undercutting is matched within a day. That is interdependence in a concentrated market, described by the industry rather than a textbook.

Advantages

Possible drawbacks

Effects of monopoly

A monopolist's demand, marginal revenue and average cost curves with money values on the axes. Output is set where marginal revenue meets marginal cost, price is read up on the demand curve, and the rectangle between price and average cost is the profit.
A monopolist's demand, marginal revenue and average cost curves with money values on the axes. Output is set where marginal revenue meets marginal cost, price is read up on the demand curve, and the rectangle between price and average cost is the profit.OpenStax, Principles of Economics 3e, CC BY 4.0, section 9.2

Disadvantages

Possible advantages

Government responses to monopoly

Each has drawbacks: a price cap set too low may deter investment, regulation costs money to enforce, and governments may lack the information to set rules correctly (government failure).

Worked example

A country has one company supplying tap water.

High start-up costs, laying a second network of pipes would be enormously expensive → this is a natural monopoly, with very high barriers to entry → the firm faces no competition, so it could charge high prices and provide poor service, knowing customers cannot switch.

But a single supplier is genuinely cheaper here. Two competing pipe networks would double the fixed costs and raise average cost for everyone. So breaking it up would make things worse.

The sensible response is regulation: a government regulator caps the price and sets minimum standards for water quality and leakage.

Evaluation. The regulator has to know the firm's true costs to set the cap fairly, and only the firm holds that information. Set the cap too high and consumers are exploited; too low and the firm cannot afford to maintain the pipes. That difficulty is a genuine limitation worth stating.

Common exam mistakes

Exam technique

Structure comparisons around the four things the syllabus names: price, choice, quality/efficiency, and profit. Covering all four gives a complete answer.

Always explain why a monopoly can behave as it does, because barriers to entry stop competitors arriving. That causal step is where the marks are.

For evaluation, the natural-monopoly case is the strongest counter-argument, and the regulator's information problem is the strongest limitation of the remedy.

Building an answer

4 marks, "Explain two features of a competitive market."

There are many buyers and sellers, so no single firm is large enough to influence the market price, each is a price taker.
There is freedom of entry and exit, so if firms in the market are earning high profits, new firms can enter and compete those profits away.

6 marks, "Analyse the effects of a monopoly on consumers."

A monopolist faces no competition, so it can restrict output and charge a price above the competitive level, which reduces consumer surplus and makes consumers worse off.
Choice is limited, since there is only one supplier and no alternative to switch to.
Without competitive pressure the incentive to improve quality or control costs is weaker, so service may deteriorate.
Against this, a monopoly may achieve economies of scale unavailable to smaller firms, and its supernormal profit can fund research and development, so consumers may gain lower costs and better products over time, particularly where the industry is a natural monopoly.

Competition against monopoly

Competitive marketMonopoly
Number of firmsManyOne dominant
PriceDetermined by the market; firms are price takersSet by the firm; it is a price maker
Barriers to entryLowHigh
Profit in the long runNormalSupernormal can persist
Choice for consumersWideLimited
EfficiencyPressure to keep costs lowWeaker pressure

Barriers to entry: the reason monopoly persists

Legal barriers such as patents and licences; economies of scale that leave an entrant at a cost disadvantage; high sunk costs that cannot be recovered on exit; brand loyalty built by heavy advertising; and control of an essential input or distribution channel.

Without barriers, high profits attract entry and the monopoly erodes. Barriers are what make market power durable, which is why competition authorities focus on them.

A real case to quote

Google search. Its share of search rests less on legal protection than on data, more searches produce better results, which attract more searches. Regulators in the EU and US have focused on default-placement agreements precisely because those are the barrier, not the technology itself. A modern illustration that barriers to entry need not be legal or physical to be effective.

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