The judge in the trial of former Anglo Irish Bank Chief Executive David Drumm has told the jurors the Financial Regulator could not condone criminal behaviour.
Judge Karen O'Connor has begun her charge to the jury at Dublin Circuit Criminal Court.
Mr Drumm denies being involved in a conspiracy to dishonestly engage in transactions between Anglo, Irish Life and Permanent and Irish Life Assurance, between March and September 2008, to make Anglo's balance sheet look better by €7.2bn.
He also denies knowingly presenting the false figures to the market in December 2008.
Judge O'Connor told the ten men and four women on the jury that 2008 was undoubtedly a time of unprecedented financial crisis.
But she said what the Central Bank and Financial Regulator knew about what was going on in Anglo and Irish Life was irrelevant to the issues in this trial.
The judge said the Financial Regulator could not condone criminal behaviour.
Those engaged in banking may have frantically been trying to keep the bank going and to keep its doors open, she said, but necessity did not provide any defence to the charges the jury had to consider.
Judge O'Connor said that if a person stole food from a shop to feed a hungry child, this would still constitute theft, even if the person told a garda what they were about to do.
She told the jurors to concentrate on whether or not there had been a conspiracy to engage in transactions dishonestly to create a false and misleading impression with the intention of causing loss or the risk of loss to another.
The judge reminded the jurors that they had been told not to serve if they had strong views.
She asked them to put aside any sympathies or strong views and consider the evidence in a cold, dispassionate way, based solely on the evidence they had heard and seen in the courtroom.
The judge said the presumption of innocence was the cornerstone of the criminal justice system.
Mr Drumm had pleaded not guilty and was presumed to be innocent unless the jurors decided the evidence was strong enough to convict him.
She warned them that Mr Drumm did not have to prove anything, had the right not to give evidence and they could not draw any inferences from the fact that he had not given evidence.
Judge O'Connor said it was up to the jury to decide whether or not the transactions at the centre of this case were real or not and whether or not they were entered into dishonestly with an intention to mislead.
She told them dishonesty was an essential ingredient of the offence.
It was not necessary, she said, for the prosecution to show that the plan had succeeded or that any party had suffered actual economic loss.
It was simply necessary to show an intention to mislead, causing a risk of loss.
She said that in relation to the offence of false accounting, it was up to the jury to decide if Mr Drumm knew the account was false, misleading or deceptive.
If they found he did not know or if they had a reasonable doubt about this, then they must acquit, she said.
The judge also told the jury of ten men and four women that "unfortunately" only 12 of them would eventually be allowed to deliberate and consider a verdict in this case, despite the time and effort they had all put into the case so far.
The jurors are likely to begin their deliberations tomorrow.