Clark left the Merseyside-based company earlier this month and is understood to be on gardening leave.
A new chief executive, David Steele, is already in place and the business is expected to announce further details about the appointment shortly.
Six months ago, CDMS expanded its offering through the acquisition of London-based data services business Transactis.
CDMS chief exec leaves company
Stephen Clark has left print, mail and data group CDMS after three-and-a-half years as chief executive.
