Guidance
Mergers: how they are investigated
Information for businesses about how the Competition and Markets Authority (CMA) investigates mergers, including processes, timelines and possible outcomes.
Documents
Details
This page explains how mergers between businesses are investigated by the Competition and Markets Authority (CMA).
It’s a simple guide for businesses to help you understand:
- what counts as a merger
- our role in merger control
- what sort of mergers we review
- how to tell us about a merger
- how we assess the effect of a merger on competition
- how our investigation works, how long it takes and what you need to do
- what the possible outcomes are
For more detailed information about our remit and processes, read our guidance on the CMA’s jurisdiction and procedure (CMA2).
If you’re ready to tell the CMA about your merger, find out how to notify the CMA.
Updates to this page
Published 29 April 2025