The former chief executive of the Manx Electricity Authority will give evidence today about the circumstances surrounding the taking out of unauthorised loans, totalling £120 million.
Mike Proffitt, who retired from the MEA in 2005, will go before the Tynwald Select Committee which is investigating the matter, at 10.30am.
When Treasury Minister Allan Bell gave evidence in March, he said the whole blame for the MEA's problems with government could be laid at the door of Mr Proffitt.
The authority's former finance director Clive Wilcox and former chairman John McCallion will give evidence this afternoon.
All the evidence will be taken in public.