AIB could owe the Revenue between £25 million (€38 million) and £35 million in DIRT tax arising out of bogus non-resident accounts held between 1986 and 1991.
As part of its "look-back" exercise this year, the Republic's biggest bank suggests any outstanding DIRT liabilities are well below the £100 million initially alleged in a newspaper report.
The look-back does not extend to the non-resident accounts held at AIB Capital Markets, many of which are held by multinational corporations.
The bank's estimates are based on the premise that all non-resident accounts which were reclassified as eligible to pay DIRT were bogus for the entire period before 1991. Within this category, some reclassifications would have been genuine, for example, in the case of returning emigrants, according to the report.
AIB began to reclassify bogus non-resident accounts as liable for DIRT tax in 1991. It had initially estimated the total amount held in bogus non-resident accounts at up to £600 million, later estimated at £500 million.
AIB informed the Central Bank that it had "misclassified" up to £500 million of its deposits as non-resident accounts. These accounts were in fact held by Irish residents, it said.
Central Bank records show that AIB's group financial director, Mr Kevin Kelly, outlined the problem of the misreporting of accounts for DIRT purposes to the bank in April 1991. At the meeting the AIB was told to get its "house in order" by June of that year.