Paul Troy, the Royal Mail's head of marketing, confirmed that the competing agencies Grey Worldwide London, M&C Saatchi and J. Walter Thompson London had not been taken into a second round of intensive research.
However, he said that AMV had not yet been officially appointed and would have to go through a three-week process of presenting more creative concepts and completing contract negotiations.
"We had four of the major groups pitching and envisaged a second stage taking two forward but, based on the presentations, we have decided to take just AMV forward," Troy announced. "The process is not a formality - AMV will develop further creative for us and we need to find a strong commercial agreement. We are working exclusively with it but it must deliver on two fronts to be appointed."
The contract, which Troy aims to have signed by the beginning of June, will initially be for a three-year period.
AMV, which presented with the direct agency Proximity London and the design agency Wolff Olins, fought off competition from: Grey and its below-the-line sister agency Joshua; M&C Saatchi, Saatchi Village and Lida; and JWT, OgilvyOne and Landor.
The incumbent, Bates UK, failed to make the agency shortlist to repitch for the business.
Royal Mail launched the review process in the last week of February this year, examining more than 30 of its agency contracts, with the intention of reducing the number of agencies on its roster by developing a more integrated marketing approach.
It has cut its overall advertising and marketing budget from £80 million in 2002 to between £50 million and £60 million this year.
The only part of the Royal Mail advertising and marketing business that will not be affected is the media planning and buying account, which is held by Carat.
The account excludes the contracts for the Post Office and Parcelforce Worldwide divisions.