The company's advertising business is split between CHI and M&C Saatchi with the former handling the Mint credit card, as well as loans and mortgages, and the latter handling the NatWest business.
M&C will continue to work on the RBS Corporate account, which features activity backing the brand's sponsorships.
CHI has already launched its first retail work for RBS with a New Year campaign featuring Sally Phillips, star of 'Smack the Pony'.