Collection

Competition Act 98 guidance: CMA investigations and procedures

Information on CMA investigation procedures, prosecutions and the application of competition law.

• From: Competition and Markets Authority
• Published: 31 March 2014

You can also visit our Competition law guidance for advice for businesses on complying with competition law.

Some of this guidance was originally published by the Office of Fair Trading (OFT) and has been adopted by the CMA board. Please see individual publication pages for full details.

CMA investigations and prosecutions

• CMA investigation procedures in Competition Act 1998 cases: CMA8
  • 2 January 2025
  • Guidance
• Cartel offence prosecution: CMA9
  • 12 March 2014
  • Guidance
• Appropriate CA98 penalty calculation: CMA73
  • 16 December 2021
  • Guidance
• Approval of redress schemes for competition law infringements
  • 14 August 2015
  • Guidance
• Memorandum of understanding between the CMA and the Crown Office, Scotland
  • 9 July 2014
  • Corporate report
• The Code of Practice for Victims of Crime in England and Wales and supporting public information materials
  • 29 January 2025
  • Statutory guidance

Application of competition law

• Abuse of a dominant position: OFT402
  • 1 December 2004
  • Guidance
• Agreements and concerted practices: OFT401
  • 1 December 2004
  • Guidance
• Assessment of market power: OFT415
  • 1 December 2004
  • Guidance
• Market definition: OFT403
  • 1 December 2004
  • Guidance
• Services of general economic interest exclusion: OFT421
  • 1 December 2004
  • Guidance
• Trade associations and professional/self-regulating bodies and competition law: OFT408
  • 1 December 2004
  • Guidance
• VABEO Guidance
  • 20 July 2022
  • Guidance
• Guidance on Horizontal Agreements
  • 16 August 2023
  • Guidance

Cartels and leniency

• Cartels: come forward and apply for leniency
  • 31 March 2014
  • Guidance
• Leniency and no-action applications in cartel cases: OFT1495
  • 24 September 2020
  • Guidance

Private litigation

• Competition law court proceedings: serving documents on the CMA
  • 4 June 2025
  • Guidance

Warning and advisory letters

• How to respond to a warning or advisory letter from the CMA
  • 14 January 2016
  • Guidance

Published 31 March 2014