The bank is thought to have hired the AAR to draw up a longlist of agencies to pitch for the business, held by Tequila\London. Abbey's purchasing department is also thought to be contacting shops.
Abbey has been gradually reviewing its agency relationships since it was taken over by Grupo Santander in November 2004. In March, Carat added the £8 million digital media account to the £26 million offline media account it won in November. The creative account was moved into WCRS in March last year.
WCRS created a red square branding device, which is expected to be carried into Abbey's direct marketing.
Tequila inherited Abbey's £11 million DM account when it merged with TBWA\GGT at the beginning of last year.
An Abbey spokeswoman would not confirm a review was taking place.