Under chapter I of the act, agreements, decisions or concerted practices between undertakings which:

• May affect trade within the UK; and
• Intend to prevent, restrict or distort competition within the UK, are prohibited.

Common examples of such agreements are where two or more competing undertakings agree to fix the prices at which they sell their products to customers, or that each will sell to a particular type of customer.

Chapter II of the act also prohibits undertakings from abusing, in a way that may affect trade within the UK, any dominant market position they may hold. For example, a dominant undertaking (usually having at least 40 per cent of the relevant market share) pricing its products unfairly or selling products at a loss, where smaller competitors are unable to do so, may be an abuse of a dominant position.