
David Steele, who joined CDMS in June from Dunnhumby, becomes chief executive of the merged business.
Chris Morris, the former managing director of Transactis who launched the company in 2004, will remain with the business as a non-executive director and advisor.
Data will be at the heart of the company's activities, although it will continue to extend its print and mail business as Transactis Document Solutions, a division of the new merged operation.
Retail transaction database Transactis sells data from the 160 home-shopping and online brands that make up its membership. CDMS handles 1.5% of all UK mail and 7% of all B2C mail.
Transactis clients include Nationwide, Betfair, HM Revenue and Customs, Damart and Shop Direct Group.
The new Transactis will be jointly based across two sites in London and Liverpool.
"The Transactis data pool and customer transactions coupled with their reputation and industry profile makes Transactis the logical identity to take us forward," Steele said.