It has sent out a request for information and is expected to draw up a shortlist next month.
The selected agency will be hired to promote Gartmore investment products to UK consumers and independent fund managers.
Rapier, the incumbent, will repitch for the business, which it won from Clark McKay & Walpole in 2006.
The company has been a long-term sponsor of The Barbarians rugby union team and was heavily visible in their game against England at Twickenham last month.
It has also hired River Publishing to produce Investment Perspective, a monthly magazine designed to keep professional investors informed of financial markets and its new investment products.
A spokeswoman for Gartmore said: "I'd like to stress that this selection process is very much in its early stages and the incumbent agency is still very much part of this pitch process."