In early November, Gartmore appointed investment bank Goldman Sachs to lead a 'strategic review', including a significant cost-cutting programme and potential sale after the departure of key staff.
It emerged this week that Gartmore has cut staff numbers by ten per cent as it strives for long-term survival.
M:Communications had won a brief to lead Gartmore's IPO in late 2009 and was retained after the listing. But the firm has had a troubled 2010 and has seen its share price drop by about 60 per cent during the course of the year.
It is thought that Goldman Sachs was instrumental in the decision to dispense with M:Communications and use Brunswick to communicate the restructuring process and likely sale or merger.
Brunswick has been working for the firm since the appointment of Goldman Sachs.
Andrew Garfield and Gill Ackers are leading Brunswick's involvement on the account.
Gartmore's shares first plummeted in March after the suspension of star fund manager Guillaume Rambourg, who was accused of breaking internal rules.
The company revealed that investors withdrew more than £1bn in the wake of his suspension.
Investor confidence took a further battering at the time of the restructuring announcement, with the retirement of Roger Guy, who ran Gartmore's flagship European Large Cap fund management division.
Gartmore hopes to complete a sale or merger by the end of the year. Rivals Schroders and Aberdeen Asset Management have ruled themselves out of the running, but others such as Henderson, Hellman & Friedman and Artemis continue to be linked.
Both M:Communications and Brunswick were unavailable for comment.