Online platforms and digital advertising market study

The Competition and Markets Authority is carrying out a market study into online platforms and the digital advertising market in the UK.

Administration timetable

Date Action
2 July 2020 Deadline for publication of final report
2 January 2020 Deadline for the decision on whether to make a market investigation reference
30 July 2019 Deadline for responses to the invitation to comment
3 July 2019 Launch of market study



Media enquiries

Any media enquiries should be directed to

Personal information

The CMA may collect, use and share personal data for its market studies under the Enterprise Act 2002. This includes processing personal data for the purposes of the General Data Protection Regulation and the Data Protection Act 2018.

For more information about how the CMA handles personal information, see the CMA’s Personal Information Charter.

Launch of the study

3 July 2019: The CMA has launched a market study into online platforms and the digital advertising market in the UK. We are assessing three broad potential sources of harm to consumers in connection with the market for digital advertising:

  • to what extent online platforms have market power in user-facing markets, and what impact this has on consumers
  • whether consumers are able and willing to control how data about them is used and collected by online platforms
  • whether competition in the digital advertising market may be distorted by any market power held by platforms

We are inviting comments by 30 July 2019 on the issues raised in the statement of scope, including from interested parties such as online platforms, advertisers, publishers, intermediaries within the ad tech stack, representative professional bodies, government and consumer groups.

Digital markets strategy

This study is part of the CMA’s Digital Markets Strategy, which sets out our broad approach to protecting consumers in the digital economy while ensuring robust, competitive digital markets.

Published 3 July 2019