Mineral Resources has admitted it has been investigating the tax evasion scheme devised by its billionaire managing director Chris Ellison for more than two years, but denied it needed to tell its investors because the board did not think it would affect the miner’s share price.

The Perth-headquartered diversified miner made that disclosure in response to questions from the ASX after the offshore tax racket was revealed by The Australian Financial Review. The scheme involved selling machinery to MinRes at inflated prices through a British Virgin Islands-incorporated vehicle, the profits of which were shared by Mr Ellison, former chairman Peter Wade and four other founding executives at the mining company.