The UK's Competition and Markets Authority has said that the proposed merger of two data companies is cause for concern.

Market insight company Nielsen operates in over 100 countries and employs approximately 44,000 people worldwide.

Marketing analytics Ebiquity, headquartered in London, employs around 1,000 people and last year turned over £86m.

Nielsen and Ebiquity, both of which analyse information on company advertising activity, are the only suppliers of this intelligence across a broad range of UK media.

The CMA says that other firms do offer this service for digital advertising, but no other firms competes for detailed intelligence across all UK media channels.

It added that the data companies are each other’s closest competitor in the supply of intelligence on international advertising to UK customers, and that they face only limited competition from other suppliers for this service.

After 20th June the CMA said it will conduct a more in-depth investigation unless the parties offer a solution to address competition concerns.