Competition – guidance

Guidance on the CMA’s investigation procedures in Competition Act 1998 cases: CMA8

Guidance for businesses and their advisers detailing the approach and procedures used by the CMA in the exercise of its investigation and enforcement powers under the Competition Act 1998.


This guidance is aimed at businesses, legal communities and other interested parties. It sets out the CMA’s procedures and explains the way in which the CMA conducts investigations into suspected competition law infringements.

Information on how the CMA handles information and complaints about businesses is also available.

Please note:

  • The fines that could be imposed on summary conviction for certain criminal offences referred to in this document were subject to caps of £5,000 or above when this guidance was published. These caps have since been removed and these offences are now punishable by a fine of any amount.

  • The OFT451 guidance on involving third parties in Competition Act investigations has now been withdrawn. Please disregard any references to OFT451 in this guidance.