Tequila will work with the bank to develop and market partnerships with high-street retailers, and will create a range of mailings to be sent out throughout the year.
Morgan Stanley, which is one of the biggest spenders on direct marketing in the UK, previously worked with Tullo Marshall Warren, which repitched for the account against Tequila and an unnamed agency.
Tequila's appointment does not affect Morgan Stanley's corporate direct account, which is currently managed by integrated agency Joshua. Leo Burnett handles the bank's global advertising business.
Morgan Stanley and Tequila were both unavailable for comment.