The most damaging insight yesterday into the workings of the ACC bank came from its former chairwoman, Ms Gary Joyce, who described a culture of non-compliance with DIRT legislation and a general disregard for the bank's board of directors by management.
Ms Joyce resigned her position in April, shortly after she was omitted from the new board of directors charged with implementing the merger and flotation of ACC and TSB banks.
The former chairwoman said her three-year term of office was "a very difficult experience", and she described how certain information was deliberately withheld from her at various stages.
Yesterday she told the committee that she was in the job for 14 months before she be came aware of the bank's substantial shortcomings in the application of DIRT.
Ms Joyce also said it was quite well known that ACC's management team had never treated the board of directors as if it had a serious role to play.
She stressed that ACC was not alone when it came to expanding its non-resident deposit base and was operating in an environment where, if a branch refused to provide this facility for its customers, they would simply take their business elsewhere. Even so, as Mr Sean Ardagh TD put it, the Comptroller & Auditor General's report points to ACC as being one of the worst offenders when it came to providing a haven for hot money between 1986 and 1998.
The former chief executive, Mr John McCloskey, acknowledged that the bank had problems when it came to complying with the law on deducting DIRT but he stressed it also had much bigger problems around that time - staying solvent.
He reminded the committee of the bank's dire financial circumstances. "We were focused on making sure the bank didn't collapse, but that doesn't imply we turned a blind eye to compliance. We took steps to improve compliance," he explained.
Documents discovered by the committee show that the bank began to take some formal steps to ensure that all non-resident accounts were genuine in 1992, when branch managers were requested to provide written assurances that they held declarations from customers verifying their non-resident status.
Just half of the branch managers bothered to reply by the given deadline and an internal audit report the following year stated that the assurances given had been found to be "materially untrue" and were "indicative of an attitude to banking standards and to legal requirements which need to be sharply reversed".
A common theme was the general inertia of branch managers to demands to clean up their non-resident accounts. It was put to Mr McGing that the bank had encouraged its managers to operate "independent fiefdoms" in an attempt to boost the ailing fortunes of the bank.
An external auditor's report in 1992 estimated ACC had a potential liability for unpaid DIRT on bogus non-resident accounts of £17 million. ACC does not accept this position and only last year made a voluntary interim settlement to the Revenue of £1.4 million, following the reclassification of £7.7 million of non-resident deposits.
Like AIB, ACC believes it was granted an amnesty in relation to any DIRT arrears arising out of accounts opened before 1992. After a meeting with the Revenue, the bank understood that once it agreed to put its house in order it would face no further demands for unpaid DIRT.
Mr McCloskey described his "shock" last year to discover that the bank's view didn't coincide with the Revenue's on this and it handed over the £1.4 million subsequently. The Revenue is continuing its DIRT audit and is trying to establish ACC's total DIRT liability. At this stage that liability lies somewhere between £1.4 million and £17 million.
If the higher figure is the one demanded by the Revenue, this suggests the bank could have sheltered up to £170 million in hot money during the 12 years under investigation.
And judging by its evidence so far, the State-owned bank may also have handed management gurus a worst-case scenario of a breakdown in corporate governance.