TDA, which was appointed without a pitch, has been asked to create ongoing direct marketing and CRM activity, including the launch of a member benefits in the first quarter of the year, to assist the brand in developing its remit as mutual finance provider.
The company said its new positioning would aim to enhance its reputation for providing a localised and in-depth range of products in the financial services sector.
Claire Bayliss, director of marketing at Derbyshire Building Society, said: "Our repositioning requires strategic insight and vision as well as in-depth understanding of financial services.
"With its proven track record in developing compelling propositions that resonate with target audiences, TDA was the natural choice."
In November, Derbyshire Building Society hired contract publishing firm Wardour to produce a new customer publication targeting 400,000 of its members.