The AAR is overseeing the process and is understood to have briefed Euro RSCG London, Leo Burnett, DDB London, St Luke's and McCann Erickson.
Leslie Butterfield, a partner at The Ingram Partnership, is acting as a consultant for the review, which is being led by Wendy Wrigley, the Co-operative Group's director of corporate affairs.
Butterfield 8 and Innocence, the strategic brand consultancies, have been working on developing a new brand identity since last year, but the Co-op has now decided to go through the AAR as it looks to position many of the Co-op brands under a single banner.
An agency is expected to be appointed before the end of the year.
Separately, the Co-op is conducting a review of its creative account to promote its membership programme, which incorporates its financial services and funeral and insurance brands.
The Haystack Group, which is overseeing the process, has shortlisted McCann Erickson, Farm, Rapier, WCRS and St Luke's to pitch for the business.
This coincides with plans to relaunch the Co-op's dividend scheme to members, which is currently under consideration.
The company, which was launched in 1844, has so far struggled to shake-off it image of being unadventurous, compared with its competitors.
The Co-operative Group operates more than 3,000 retail outlets, 1,600 food stores and 500 funeral branches nationwide.