Ausdrill chief executive Ron Sayers should know his fate this week on a conspiracy charge arising from his secret interest in underground mining contractor Barminco.
A Supreme Court jury is set to head out as early as today to consider a verdict for Mr Sayers and his alleged co-conspirator, Barminco founder Peter Bartlett.
The retrial of the lifelong friends on charges of conspiring to swindle the Commonwealth started on August 4 and had been expected to last up to eight weeks.
But prosecution and defence lawyers got through evidence and submissions far quicker than expected, after a trial last year was extended by the inclusion of tax scheme promoter Greg Dunn.
Dunn was convicted of conspiring with former Barminco accountant and director Trevor Neil Thomson, a long-time adviser to Mr Bartlett and a director of Barminco. The jury acquitted Thomson's former protege Deborah Grace.
The jury could not reach verdicts on conspiracy charges against Mr Sayers and Mr Bart- lett over dealings allegedly designed to protect a $50 million tax minimisation scheme devised by Dunn.
Thomson has been the major prosecution witness in both cases, after pleading guilty to conspiracy in 2010 and agreeing to help Federal authorities.
Justice Eric Heenan told the jurors on Friday the accountant had behaved discreditably in concealing a secret commission he was receiving from Dunn related to the minimisation schemes.
In weighing up his evidence, the judge said it was up to the jury to decide whether Thomson should be given credit for owning up to his behaviour and helping authorities.
Prosecutors claim Mr Bartlett and Mr Sayers were involved in a conspiracy that included the falsification of minutes and shifting more than $7 million into the schemes.
However, the accused men have pointed the figure at Thomson and Dunn, claiming the advisers carried out fraudulent dealings to maximise their own cuts from the minimisation schemes.
Their dealings became caught up last decade in a major Australian Crime Commission investigation into people who had dealings with Swiss tax scheme operator Strachans.
The scheme that sits at the centre of the conspiracy charges was not devised by Strachans but was the brainchild of Mr Dunn, a self-styled developer of minimisation arrangements.
However, $32.4 million in promissory notes created as part of the minimisation scheme were transferred by Mr Sayers and Mr Bartlett in June, 2004, to Jersey trusts controlled by Strachans boss Philip Egglishaw.
Mr Sayers continues in his role as Ausdrill managing director while fighting the charges and has been backed by the Ausdrill board.
Ausdrill chairman Terry O'Connor was in court on Friday to hear Justice Heenan sum up the case to the jury panel of 12 men and four women. The panel will be cut down to 12 members by a ballot before Justice Heenan sends them out to try to reach a verdict.
The judge will continue his summation this morning.