Cow pitched against Fishburn Hedges, Armadillo PR and Haslimann Taylor to run the campaign, which has a marcoms budget of £1.5m over two years.
Liz Male Consulting founder Liz Male, who has handled trade PR for TrustMark's debut, said the campaign would be PR-led with a focus on local media.
TrustMark follows the collapse of Quality Mark, which attracted just 500 member firms.
Have you registered with us yet?
Register now to enjoy more articles and free email bulletinsRegister