Report anti-competitive business practices

Last updated: 24 October 2017

Report businesses that you think are acting in an anti-competitive way to the Competition and Markets Authority (CMA).

Fill in the form to report anti-competitive practices and send it to

You can also call the CMA to make a report.

CMA enquiries centre
0203 738 6000

Read about how the CMA investigates anti-competitive behaviour.

Industry authorities

You can report concerns about anti-competitive behaviour in certain sectors to an industry authority. These are:

Types of anti-competitive behaviour

Anti-competitive agreements can include price-fixing, limiting production to drive up prices, agreeing not to sell to a competitor's customers.

These agreements can be formal or informal and may include 'shared understandings','concerted practices' or 'gentleman's agreements' where businesses cooperate or act together.

You should also report businesses that abuse a dominant market position - eg by offering unfair prices to customers or suppliers, refusing to supply, or limiting production.

Report a cartel

A cartel is an agreement between businesses about not competing with each other - eg by price-fixing, bid-rigging, output quotas or restrictions, or market-sharing arrangements. Cartels are usually secret.

CMA cartels hotline
Telephone: 0800 085 1664 or 020 3738 6888

You may get a financial reward for information that leads to an investigation.

Read the guide cartels and the Competition Act for more information.

You may be treated with leniency if you report a cartel you've been involved with.


Businesses may be fined up to 10% of their worldwide turnover if they enter into an anti-competitive agreement or abuse a dominant market position.

You may be fined or sent to prison for up to 5 years if you are involved in cartel activity. Company directors may be disqualified from being a director for up to 15 years.