''How stupid could they be if they thought it was material and they continued doing what they did?'' asked Justice Lindsay Foster.

''There could be many answers to that, one of which is: very stupid,'' replied the shareholders' barrister, John Sheahan, SC.

Mr Sheahan was describing the risks to AWB's reputation and its ''single desk'' export monopoly of disclosure that its payments to a Jordanian trucking company, Alia, were being passed on to the Iraqi government which was under United Nations sanctions.

On the third and final day of his opening address, Mr Sheahan said Australia's continuous disclosure regime did not allow AWB's executives to think ''as they lie awake at night in bed worrying about it, wouldn't it be much better if we didn't say anything?''.

Trying to protect the business in this way was counter to ''the whole point'' of the continuous disclosure law, he said.

''The statute requires information of this kind to be disclosed even if, perhaps especially if, the disclosure is going to cause the share price to tank,'' he said.

''It's difficult to imagine that someone who was conscious of this material didn't think that disclosure would put the single desk at risk.''

When the nature of the payments was revealed at the 2006 commission of inquiry headed by Terence Cole, QC, stockmarket analysts focused on the likely effect on the single desk, he said.

Justice Foster asked whether the impact on the share price might have been different if AWB had released the information itself, perhaps saying ''we thought it was OK, it turns out it's not OK'', and promising to reform.

''If they had said that, as distinct from having, as it were, Special Agent Cole dragging it out of them daily in the press, isn't it a very different way of disclosure?'' the judge asked.

Mr Sheahan replied that there was a direct connection between AWB's breaches of the disclosure law and the impact on its share price ''of this having to be dragged out of AWB in a brutal fashion''.

AWB issued express denials, he said. ''When they should have been saying 'these things were happening' what they were saying was 'these things didn't happen','' he said.

''That conduct reinforces the consequences of the non-disclosure and is itself a contravention of the [law] because it is misleading or deceptive.''