An AIB foreign exchange official has has told the Mahon Tribunal that money lodged on behalf of Taoiseach Bertie Ahern in the O'Connell St branch was probably $45,000.
However, Rosemary Murtagh also agreed with counsel for Mr Ahern that it could have been sterling.
Mr Ahern says he was given Stg£30,000 by a Manchester businessman to spend on a Dublin rental property in December 1994.
Ms Murtagh was shown a spreadsheet of 1,000 different permutations of exchange rates at which her currency services division would have purchased the sum equivalent to over IR£28,000 lodged by Celia Larkin.
None would allow for a conversion of Stg£30,000 but one special remit rate would allow for $45,000.
Ms Murtagh agreed with tribunal counsel that it was therefore probably a dollar transaction.
But she also agreed with counsel for Mr Ahern that based on money collected from branches throughout Dublin it could have been sterling.
Manchester businessman Micheál Wall told the tribunal he gave Stg£30,000 to Bertie Ahern to be spent on a Dublin house that Mr Ahern was to rent from him.
Celia Larkin said he lodged the money given to her in a briefcase at AIB.
Earlier, Judge Alan Mahon described as offensive an accusation by counsel for the Taoiseach that the inquiry was 'pushing an agenda' in its examination of his accounts.
During angry exchanges, Judge Mahon warned Mr Ahern's counsel about his language.
The exchange occurred after Des O'Neill SC attempted to re-examine an AIB official about a tribunal letter to Mr Ahern last March.
When the question was put to AIB official Jim McNamara, he confirmed that Mr Ahern had asked last March about evidence of foreign exchange transactions in his lodgements even though the tribunal has not asked about this in their letter to Mr Ahern.
