Based on the Holmes Report’s recent Global PR Rankings the combined group will have PR income of $1.8bn, which it estimates will make it the largest PR holding company in the world.

But what about the implications for the UK PR market?

As many of the key agencies and their parent groups don’t disclose UK PR figures the data is rather sketchy – see caveats below. However based on a combination of the PRWeek Top 150 estimates for Brunswick and WPP, Omnicom, Publicis and Interpublic‘s UK agencies, as well as Huntsworth’s accounts, we can have a decent stab at what the top 5 players will look like if the merger goes ahead.

The table below shows revenue in £m for the key PR agencies within WPP, Omnicom, Publicis and Interpublic from PRWeek’s 2013 Top 150 analysis.

According to the PRWeek 150 estimate, Brunswick’s 2012 income was £53.2m.

According to Huntsworth’s 2012 annual report its UK revenues were £64.3m. This includes revenues relating to healthcare (Huntsworth Health) whereas for most of the groups above health work is often classified within a different division. The UK healthcare headcount is 23% of the total according to the report. Adjusting for this suggests a public relations UK income figure of around £50m.

On the basis of these estimates the top 5 will look as follows post merger.

1. WPP £107.0m

2. Publicis Omnicom* £92.0m

3. Brunswick – £53.2m

4. Interpublic – £52.5m

5. Huntsworth – £50.0m

Their combined fee income of c. £355m gives these five c. 18-20% of the UK market based on previous estimates from 2011 of c. £1.8bn-£2bn.

*Update – Kreab Gavin Anderson has been excluded from the analysis on the basis that Omnicom only holds a minority stake.

Caveats

All the caveats relating to the PRWeek Top 150 figures apply here, the key one being they are estimates of course!

Also bear in mind that it could well be the case that some of the estimates above include revenues relating to the UK arm of a multinational agency that were derived from work outside the UK. Equally there could be agencies within each Marcoms group that are based outside the UK that do work with UK clients.

There is also the issue of agencies that aren’t labeled “PR” and so aren’t included in this analysis that will be doing some PR based work.

These are just the ones I can think of, there are bound to be a few more.