Guidance

Mergers - the CMA’s jurisdiction and procedure: CMA2

Guidance for businesses and their advisers on CMA's procedures for operating the merger control regime under the Enterprise Act 2002.

Documents

Mergers: Guidance on the CMA’s jurisdiction and procedure (2025 - revised guidance)

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Details

This guidance provides advice and general information to companies and their advisers on the procedures used by the Competition and Markets Authority (CMA) in operating the merger control regime set out in the Enterprise Act 2002, as amended. It also includes guidance on when the CMA will have jurisdiction to review mergers under the Act. 

This guidance reflects the jurisdictional and procedural changes to the mergers regime made by the Digital Markets, Competition and Consumers Act 2024 (DMCCA24) which commenced on 1 January 2025. 

2 January 2025: revised guidance published

The revised guidance takes effect on 1 January 2025 and applies to all merger cases subject to the subject to the transitional provisions in the Digital Markets, Competition and Consumers Act 2024 (Commencement No.1 and Savings and Transitional Provisions) Regulations 2024 (SI 2024/1226) summarised below. 

For more information, see the updated mergers guidance consultation page.  

The following forms and templates will be updated to reflect the relevant DMCC Act changes in due course: 

Any merger that qualifies for reference for a phase 2 investigation is subject to a fee. This is irrespective of whether a reference is made. Further information on the fees and how to pay them are in the merger fees information document.

Summary of transitional provisions

The parts of the 2025 revised guidance dealing with the DMCC Act changes related to jurisdiction, ie the increased turnover threshold (paragraphs 4.3, and 4.52 to 4.57), the share of supply test incorporating the new safe harbour threshold (paragraphs 4.58 to 4.71), and the new hybrid test (paragraphs 4.72 to 4.91) will apply to (i) completed mergers where completion took place on or after 1 January 2025 and (ii) anticipated mergers where the formal Phase 1 investigation (ie the start of the 40 working day initial period) commences on or after 1 January 2025. Chapter 4 of the April 2024 guidance will continue to apply to (i) completed cases where completion took place prior to 1 January 2025, (ii) anticipated cases where the formal Phase 1 investigation (ie the start of the 40 working day initial period) commenced prior to 1 January 2025. For the avoidance of doubt, Chapter 4 of the 2024 guidance will also apply to all cases referred to phase 2 prior to 1 January 2025.   

The parts of the 2025 revised guidance dealing with the new statutory phase 2 fast track process (paragraphs 7.13 to 7.26) will apply to mergers (excluding mergers of water enterprises and mergers of energy networks) where the formal Phase 1 investigation (ie start of the 40 working day initial period) commences on or after 1 January 2025. The administrative fast track process explained in the April 2024 guidance (paragraphs 7.14 to 7.17) will continue to apply to all cases where the formal Phase 1 investigation (ie the start of the 40 working day initial period) commenced prior to 1 January 2025.  

The parts of the 2025 revised guidance dealing with the extension of the phase 2 timetable by mutual agreement between the CMA and the merger parties (paragraph 11.70) will apply to mergers (including energy and public interest mergers) referred to Phase 2 on or after 1 January 2025. The extensions explained in the April 2024 guidance (paragraphs 11.69 and 11.70) will continue to apply to all cases referred to Phase 2 prior to 1 January 2025.  

The parts of the 2025 revised guidance dealing with penalties for supplying false or misleading information (paragraphs 9.34 to 9.37) will apply to cases where false or misleading information was provided in relation to a section 109 notice or a section 5 information request issued on or after 1 January 2025. The April 2024 guidance (paragraphs 9.12 and 9.18) will apply to false or misleading information provided in relation to a section 109 notice or a section 5 information request issued prior to 1 January 2025.  

The parts of the 2025 revised guidance dealing with penalties for breaches of section 109 notices (paragraphs 9.38 to 9.43) will apply in relation to section 109 notices issued on or after 1 January 2025. The April 2024 guidance (paragraphs 9.11, 9.19, and 11.22) will apply in relation to section 109 notices issued prior to 1 January 2025.  

Updates to this page

Published 10 January 2014
Last updated 2 January 2025
  1. Updated revised CMA2 guidance published.

  2. Updated guidance published

  3. Updated CMA2 guidance to reflect changes to the Enterprise Act 2002 brought about by the National Security and Investment Act 2021.

  4. Updated CMA2 guidance published.

  5. Explanatory note added in reference to the Enterprise Act 2002 (Specification of additional section 58 consideration) Order 2020, which adds a further public interest consideration to section 58 of the Enterprise Act 2002.

  6. Added Water mergers explanatory note

  7. First published.

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