AQA A-Level Economics (7136)

## Learning Outcomes

- Define **monopoly** and **monopoly power** accurately for AQA A-Level Economics
- Explain how a monopolist sets output and price using **MC = MR**
- Identify the main sources of monopoly power, including **barriers to entry**
- Calculate and interpret **concentration ratios** and abnormal profit
- Compare monopoly with perfect competition in terms of price, output and efficiency
- Evaluate the costs and possible benefits of monopoly, including **natural monopoly** and **dynamic efficiency**

## AQA A-Level Economics (7136) Syllabus

For the AQA A-Level Economics (7136), you are expected to understand monopoly and monopoly power, with a focus on the following syllabus points:

- Know the difference between **monopoly** as a market structure and **monopoly power** as control over price, output or market conditions
- Understand that a monopolist faces a downward-sloping **average revenue** curve and that **marginal revenue** lies below it
- Explain why profit is maximised where **marginal cost equals marginal revenue**
- Identify how **barriers to entry** increase monopoly power and help firms keep abnormal profit in the long run
- Use and interpret **concentration ratios** as indicators of market concentration
- Understand why monopoly is usually **allocatively inefficient** and may be **productively inefficient**
- Assess possible benefits of monopoly, including **economies of scale**, **natural monopoly** and **dynamic efficiency**
- Recognise that contestability affects how much power a dominant firm actually has

## Test Your Knowledge

_Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, look more closely at that area during your revision._

1. What is the difference between monopoly and monopoly power?
2. Why does a monopolist have a downward-sloping demand or AR curve?
3. How does a firm choose price once it has found the profit-maximising output?
4. What is a concentration ratio, and what does a high one suggest?
5. Why might a monopoly still be beneficial in some markets?

## Introduction

Monopoly is one of the core market structures in A-Level Economics. It matters because it shows what can happen when competition is weak: firms may gain the power to raise prices, restrict output and earn long-run abnormal profit. At the same time, monopoly is not always harmful. In some industries, one large firm may produce at lower cost than many small firms.

![Monopoly and monopoly power, including MC=MR output determination, downward-sloping AR and MR, barriers to entry, concentration ratios, and abnormal profit.](https://static.pastpaperhero.com/images/aqa-a-level-economics-7136-market-structures-and-competition-monopoly-and-monopoly-power_00.png)

_Monopoly pricing is presented through AR, MR, MC and AC relationships, with market dominance reinforced by entry barriers and concentration._

For exam answers, you need more than a definition. You need to explain diagram logic, apply ideas such as barriers to entry and concentration, and then evaluate using efficiency, welfare and contestability.

> **Key Term: monopoly**
> A market structure in which one firm dominates the market. In AQA-style exam use, monopoly is often treated as a firm with at least **25% market share**, though pure monopoly means a single seller.
>
> **Exam Warning:**
> Do not rely on keyword recognition alone; check the precise condition, exception, calculation step, or evidence the question requires.

### Monopoly and monopoly power: the core distinction

Students often use these terms as if they mean the same thing. They do not.

**Monopoly** refers to the market structure or degree of dominance in a market. **Monopoly power** is broader. It means the ability of a firm to influence price, output or other market conditions.

A pure monopolist is the only seller, so it clearly has monopoly power. But firms in other imperfectly competitive markets can also have monopoly power if they face weak competition, strong brand loyalty or few close substitutes.

> **Key Term: monopoly power**
> The ability of a firm to influence price, output or other conditions in the market.

This is why a firm does not need 100% of a market to have significant power. A dominant supermarket chain, technology platform or energy supplier may still be able to act as a **price maker** rather than a **price taker**.

> **Key Term: price maker**
> A firm with enough market power to influence the price it charges, rather than simply accepting the market price.

Monopoly power tends to be greater when:

- the firm has a high market share
- demand for its product is price inelastic
- there are few close substitutes
- consumers are loyal to the brand
- barriers to entry are strong

A useful exam link is that a high market share suggests power, but it does not prove it. If the market is contestable, the threat of entry may still discipline the firm.

> **Test Tip:**
> If the question says "explain the difference between monopoly and monopoly power", make the contrast explicit. Monopoly is a market structure or market share idea. Monopoly power is the degree of control over price and output.

### Revenue, profit maximisation and long-run abnormal profit

A monopolist faces the market demand curve. That means its **average revenue** curve is downward sloping. To sell more output, it usually has to lower price. Because the lower price applies to all units sold, **marginal revenue** falls faster than average revenue and lies below it.

> **Key Term: average revenue (AR)**
> Revenue per unit sold. In a monopoly, AR is the firm's demand curve.
> **Key Term: marginal revenue (MR)**
> The extra revenue gained from selling one more unit of output.

The profit-maximising rule is the same as in other market structures:

- produce where **MC = MR**
- then take the price from the **AR** curve at that output

This order matters. The firm does **not** set output where MC = AR. It finds output from MC = MR, then reads the price from demand.

Suppose a monopolist has the following data:

- Profit-maximising output = **80 units** where **MC = MR**
- At 80 units, the price shown on the AR curve = **£12**
- Average cost at 80 units = **£9**

Abnormal profit per unit:

- £12 - £9 = £3

Total abnormal profit:

- £3 × 80 = £240

So:

- Abnormal profit = (Price - Average Cost) × Quantity
- Abnormal profit = (£12 - £9) × 80 = £240

> **Key Term: abnormal profit**
> Profit above normal profit; calculated as the difference between price and average cost, multiplied by output.

This profit can continue in the long run if entry barriers stop new firms entering the market. That is a major difference from perfect competition, where new entry tends to remove abnormal profit over time.

Common barriers to entry include:

- **economies of scale** that make large firms lower-cost producers
- **legal barriers** such as patents or licences
- **product differentiation** and strong branding
- **high sunk costs**, such as advertising or specialist capital
- ownership of key distribution networks or data

> **Key Term: barriers to entry**
> Obstacles that make it difficult or costly for new firms to enter a market.

A concentration ratio gives one way to measure market concentration.

Formula:

- CRn = market shares of the largest n firms added together

Worked example:

Suppose the four largest firms in a market have shares of:

- 35%
- 20%
- 15%
- 10%

Then:

- CR4 = 35 + 20 + 15 + 10
- CR4 = 80%

This suggests a highly concentrated market.

However, evaluation is needed. A high concentration ratio suggests possible monopoly power, but it does not tell you everything. It ignores:

- how easy market entry is
- foreign competition
- how similar or different the firms are in size
- whether consumers can switch easily

> **Key Term: concentration ratio**
> The combined market share of the largest firms in a market, used as an indicator of market concentration.
>
> **Test Tip:**
> In diagram questions, students often make one key error: they choose output where MC = MR but then take price from MR. Always read the price from the AR or demand curve.
### Efficiency, welfare and why monopoly may cause market failure

Monopoly is usually criticised because it leads to higher prices and lower output than a more competitive market.

A profit-maximising monopoly is usually **allocatively inefficient** because:

- output is chosen where **MC = MR**
- at that output, price is above marginal cost
- so **P > MC**

Allocative efficiency requires **P = MC**, so monopoly under-produces relative to the socially efficient level.

> **Key Term: allocative efficiency**
> A situation in which price equals marginal cost, meaning resources are allocated to the goods consumers value most at the margin.

Monopoly may also be **productively inefficient**. With little pressure from rivals, firms may allow costs to drift upward. This is often called **X-inefficiency**: managerial slack, weak cost control or poor incentives.

> **Key Term: productive efficiency**
> Producing at the lowest possible average cost.

Consumer welfare is also affected. Compared with a more competitive market, a monopoly usually transfers some **consumer surplus** to the producer as extra profit. It also creates **deadweight loss**, meaning a net loss of total welfare because some mutually beneficial trades do not happen.

> **Key Term: deadweight loss**
> The net loss of economic welfare caused when output is restricted below the allocatively efficient level.

A strong exam comparison with perfect competition would be:

- monopoly charges a **higher price**
- monopoly produces a **lower output**
- monopoly can earn **long-run abnormal profit**
- monopoly is usually **allocatively inefficient**
- monopoly may be **productively inefficient**

But avoid absolute statements. Monopoly is not always less productively efficient. Large firms may benefit from economies of scale, reducing average costs.

### Natural monopoly, contestability and balanced evaluation

Some monopolies exist because one firm can supply the whole market more cheaply than many firms. This is a **natural monopoly**.

> **Key Term: natural monopoly**
> A market in which one firm can supply the whole market at lower average cost than several competing firms, usually because of very high fixed costs and economies of scale.

This often happens in network industries such as water supply or electricity distribution. It would be wasteful to duplicate pipes, cables or rail infrastructure across the same area.

In these cases, monopoly may bring lower costs and avoid duplication. If average costs keep falling over the relevant output range, one large producer may be more efficient than several smaller ones.

Monopoly can also be defended on **dynamic efficiency** grounds. If firms earn abnormal profit, they may be able to fund:

- research and development
- new technology
- staff training
- long-term investment

> **Key Term: dynamic efficiency**
> Efficiency over time achieved through investment, innovation, improved technology and better production methods.

This gives you a standard evaluative structure:

**On the one hand**, monopoly may reduce welfare through higher prices, lower output, deadweight loss and weaker incentives to control costs.

**On the other hand**, monopoly may lower long-run average costs, avoid wasteful duplication and support innovation.

**It depends on**:

- whether there are large economies of scale
- how strong barriers to entry are
- whether the market is contestable
- whether profits are reinvested or simply taken as dividends
- whether regulation limits abuse of power

> **Key Term: contestable market**
> A market in which the threat of new entry is strong because barriers to entry and exit are low.

Contestability matters because even a highly concentrated market may behave competitively if new firms can enter easily. The mere threat of entry can stop a dominant firm raising price too far.

How to structure an evaluative answer:

Start with a clear definition and short theory chain. Then apply it to the context. Use evidence such as market share, concentration ratio, costs, demand conditions and entry barriers. After that, weigh short-run consumer harm against possible long-run cost savings or innovation. Finish with a judgement that uses "it depends on" and states the factor that matters most.

For example, in a utilities question, the strongest judgement may be that monopoly is less harmful when it is a natural monopoly and is well regulated. In a consumer goods market with low barriers and many substitutes, monopoly power is less secure and may be less damaging.

## Key Point Checklist

_This article has covered the following key knowledge points:_

- Monopoly and monopoly power are related but different concepts
- In AQA-style exam use, monopoly is often treated as a firm with at least 25% market share
- Monopoly power means the ability to influence price, output or market conditions
- A monopolist faces a downward-sloping AR curve, and MR lies below AR
- Profit is maximised where MC = MR, and price is then taken from the AR curve
- Abnormal profit equals (Price - Average Cost) × Quantity
- Barriers to entry help monopolies keep long-run abnormal profit
- Concentration ratios measure the combined market share of the largest firms
- Monopoly is usually allocatively inefficient because P > MC
- Monopoly may also be productively inefficient because of weak competitive pressure
- Monopoly can sometimes bring economies of scale and dynamic efficiency
- Natural monopoly and contestability are major evaluation points in essay answers

## Key Terms and Concepts

- monopoly
- monopoly power
- price maker
- average revenue (AR)
- marginal revenue (MR)
- abnormal profit
- barriers to entry
- concentration ratio
- allocative efficiency
- productive efficiency
- deadweight loss
- natural monopoly
- dynamic efficiency
- contestable market


Market Structures and Competition - Monopoly and monopoly power