A-Level Economics/Perfect competition, imperfect competition and monopoly/Collusion in oligopoly
Topic anchor · Paper 1 and Paper 3

Collusion in oligopoly

Overt and tacit collusion, cartels, the incentive to cheat, and why game theory predicts the breakdown.

Why do cartels keep getting caught, and keep forming anyway?

Spec pointAQA 4.1.5.5
Edexcel A3.4.4
Pearson IALWEC13 · Unit 3
SourceCC deck · AQA-referenced
Board mapping

Where this sits on your specification

The economics does not change between boards — only the reference number and the exam style. This page is written to the concept, so find your own line below and read on.

SpecificationReferenceSection
AQA A-Level Economics 71364.1.5.5Oligopoly
Edexcel A Economics 9EC03.4.4Theme 3
Pearson Edexcel IAL EconomicsWEC13 · Unit 3Business behaviour
Section I

What this spec point covers

Overt and tacit collusion, cartels, the incentive to cheat, and why game theory predicts the breakdown.

AQA sets this out as 4.1.5.5 — Oligopoly, inside Perfect competition, imperfect competition and monopoly. The full spectrum of market structures, and the efficiency case for each. It is assessed on Paper 1 and Paper 3.

The full anchor publishes December 2026

Topic pages on this site are not written and abandoned. Each one gets the definition and the specification framing first, then the diagram drawn properly, then how the board actually examines it, and then the five branches below — added over months rather than dumped in one go.

This page is at the first stage. If you need this topic before then, the revision platform already covers the full specification interactively, and the Intelligence Briefing carries model answers on the essays most likely to appear.

Section II

Where you have already seen this

Application is worth more marks than knowledge on this specification — AO2 carries 26–29% against AO1's 20–23%. So the examples are not decoration. They are where a third of the paper lives, and the ones that earn are the ones specific enough to be checked.

01

The incentive to collude and the incentive to cheat are the same incentive seen from two sides.

02

Competition authorities routinely fine construction, freight and finance cartels, which is evidence of both halves.

03

Tacit collusion needs no meeting, which is what makes it hard to prosecute and easy to sustain.

Each of these becomes a full piece in its own right, in the branches below. What is here is the hook; the argument, the data and the essay application are what the pieces are for.

Section III

What the examiner is testing

Every question on this specification is marked against four assessment objectives, and they are not weighted equally. Most revision treats a topic as a body of knowledge; the paper treats it as four separate skills applied to that knowledge. This topic is examined as a structure and behaviour topic, so here is what each objective looks like on it specifically.

 WeightWhat it isWhat it means on collusion in oligopoly
AO120–23%Knowledge and understanding of terms, concepts, theories and modelsDefine the structure by its characteristics, not by naming a company that resembles it.
AO226–29%Application of that knowledge to economic contextsIdentify which structure the market in the question actually is, and justify the classification before using it.
AO326–29%Analysis of issues and their impact on economic agentsDerive the behaviour from the structure — price, output, profit, efficiency — instead of describing what firms do.
AO422–25%Evaluation of arguments, using evidence to support a judgementSet static against dynamic efficiency, and the short run against the long run. Almost every judgement about firms reduces to one of those two tensions.

The part worth knowing before the exam

AO2 and AO3 together carry more than half the qualification. Knowledge is the lightest-weighted objective on the paper, which is why an answer that knows everything and applies nothing lands in the middle bands. Most candidates revise AO1 because it is the part that feels like revising.
Going deeper

The five branches

Everything above is the anchor. The pieces below take it further, and each one is built to train a particular assessment objective rather than to cover the topic again. They accumulate — nothing on this page gets deleted, it gets added to.

Trains AO2
Leaf 01 · The Case
The Case: collusion in oligopoly
One firm, one market, one week of the real economy, taken apart with this topic's tools.
Planned · Jan 2027
Trains AO1 · AO3
Leaf 02 · The Diagram
The Diagram: collusion in oligopoly
The diagram drawn properly, then drawn wrongly, so the difference cannot be unseen. Ninety seconds on film.
Planned · Feb 2027
Trains AO1 · AO3
Leaf 03 · The Misconception
The Misconception: collusion in oligopoly
The thing almost every candidate believes about this and the examiner penalises.
Planned · Mar 2027
Trains AO4
Leaf 04 · The Examiner's Line
The Examiner's Line: collusion in oligopoly
The sentence that moves an answer on this topic up a mark band, taken from real marking.
Planned · Apr 2027
Trains AO1–AO4
Leaf 05 · The Question
The Question: collusion in oligopoly
A question in the board's own register, with an A answer and an A* answer side by side, annotated.
Planned · May 2027
Nearby

Related topics

Do not wait for the page

The revision platform covers the whole specification now, and the Academy marks your written answers against the framework examiners use. The library is the free layer, not the only one.

Enquire about a place See the platform