AIS is understood to be the only agency left in the running after a pitch conducted by the AAR. Rapier was involved in a final shoot-out, while FCBi and Publicis Dialog were both eliminated at an earlier stage.
The decision to relaunch Abbey's four credit cards was forced by the Abbey owner, Grupo Santander, which is moving the back-office operations of the cards in-house. The cards were previously outsourced to MBNA, which was bought last year by Bank of America - a competitor of the Abbey parent.
An Abbey spokeswoman denied a decision had been made, saying all four agencies were still involved and a decision would be made by 10 July.
Tequila\London will continue to handle the remainder of Abbey's DM business.
The agency was invited to pitch for the relaunch brief, but was eliminated at an earlier stage.
WCRS, which handles the Abbey advertising account, is not affected by the review.