AIB has one last chance today to persuade the committee that it had a deal with the Revenue Commissioners in 1991, but it must be in little doubt that it is fighting an uphill battle.
The bank is now relying on its senior counsel, Mr Dermot Glee son, to establish sufficient proof of the existence of an understanding or agreement with the Revenue in relation to its DIRT liabilities between 1986 and 1991 from his examination of Revenue officials.
Today he will question three senior Revenue officials attached to its investigation branch, Mr Tony Mac Carthaigh, Mr Paddy O Donghaile and Mr Christopher Clayton, about the disputed amnesty the bank claims to have secured almost 10 years ago.
After seven days before the committee, AIB's case has virtually collapsed. Without a written assurance from the Revenue of its understanding, the bank is finding it difficult to back up its claim.
At this stage AIB is relying on contemporaneous notes taken by its tax officials following meetings with the Revenue to support its case. But after much close examination of those notes, the fact still remains that whatever AIB's negotiators took from those meetings, the Revenue tells a different story.
Over the weekend, much was made of a note recorded by a PricewaterhouseCoopers' tax partner, Ms Mary Walsh, which initially seemed to provide for the first time some proof of the existence of a tacit understanding between the bank and the former chairman of the Revenue Commissioners, Mr Cathal Mac Domhnaill. This has now been dismissed.
But it has been established that the bank did have easy access to the highest ranking officers in the Revenue, principally through its former head of taxation, Dr Donal de Buitleir, who had previously worked there.
In her note, Ms Walsh recorded that shortly after the Sunday Independent article last year and a subsequent visit from the Revenue, the bank felt it didn't have too much to worry about. Ms Walsh reported that the bank had conveyed to her that the matter of the arrangement had been "satisfactorily resolved".
AIB's current head of taxation, Mr Philip Brennan - the person most likely to have conveyed that sentiment to Ms Walsh - told the committee these comments would suggest he believed the Revenue had accepted the existence of its earlier deal. He formed this view primarily because the Revenue failed to come back to the bank with a tax demand in the following months, he said.
He was also influenced by Dr de Buitleir's assurances to him following a meeting he had with his long-time friend, the former Inspector of Taxes, Mr Sean Mori arty. Dr de Buitleir told the committee that over lunch sometime about last June or July, Mr Mori arty said he thought AIB was probably "OK" and that its claim of a deal would hold. Mr Moriarty has, however, rejected suggestions that he had ever given any such comfort to the bank.
Contrary to the bank's assertion that the Revenue never followed up on its initial meeting, which was prompted by the Sunday Independent report, the chairman of the Revenue Commissioners, Mr Dermot Quigley, has detailed a series of correspondence and meetings between the investigation branch and AIB.
Mr Quigley has also emphatically stated that it couldn't have been expected to submit a tax demand to the bank at that stage because it is still assessing its liability.
AIB claims it was offered an amnesty on DIRT as part of an industry -wide initiative by the Revenue to stamp out the abuse of non-resident accounts. So far, the only bank to admit any knowledge of Revenue efforts at that time to encourage the banks to regularise non-resident accounts was ACCBank, although it does not contend it agreed an amnesty.
From the evidence given to the committee during the course of the hearings, it is also clear that if AIB did indeed reach an understanding with the Revenue in 1991, the basis for granting such an agreement would have been unique.
Only last year, Ms Walsh told the bank the firm was not aware of the Revenue ever having granted an amnesty to an industry group.
Meanwhile, Mr Quigley has told the committee it would have been impossible for the Revenue to have sanctioned such a massive write-off of taxes in an organisation that clearly had the ability to pay its debts.
The bank itself has demonstrated that at no stage was the disputed deal based on a full disclosure of the extent of its tax liabilities in relation to DIRT - something which is normally required in any settlement with the Revenue.
The Revenue's great weakness is that, after its discussions with AIB in 1991, it never followed through and sought a payment for DIRT arrears. Mr Quigley admits this shortcoming, blaming a lack of resources and limited powers to investigate the financial sector. However, the chairman of the Revenue reminded the committee that DIRT was a self-assessment tax and that it was up to the bank to comply with the law.