Julian Wright was well aware the offer he accepted for his stake in his family's iron ore empire was considerably below its true value, the lawyer representing his estranged siblings has said.
Mr Wright, the youngest of three children of West Australian iron ore pioneer Peter Wright, is suing his sister, Angela Bennett, and the estate of his late brother, Michael Wright, over the infamous deal in which he sold his one-third stake in Wright Prospecting in 1987 for $6.8m.
Wright Prospecting, which holds lucrative royalties over iron ore mines in WA's Pilbara region, is today worth about $4bn.
But Kristina Stern SC, representing Mrs Bennett and her brother's estate, told the West Australian Supreme Court on Friday that Julian knew at the time he was accepting an offer well below the share's full worth.
Ms Stern tendered affidavits from earlier legal battles, in which Julian Wright swore that he estimated Wright Prospecting was worth between $75m and $120m at the time he sold his stake to his siblings.
Ms Stern said Julian Wright decided to accept the offer of $6.8m in part because of the existence of an option that could have seen him bought out for just $1m, as well as a recognition that his siblings were financially constrained to pay any more.
"The reason he went into the deal was the threat of the option hanging over him, and he knew there were limited resources that Michael Wright and Angela Bennett could devote," she said.
Ms Stern produced documents written by Julian at the time that showed he had been motivated to exit the business due to his difficult relationship with his siblings and his father.
"By reason of events that occurred during my father's lifetime I do not wish to have any involvement with his estate or the family's business interests," Julian wrote at the time.
In one affidavit, he said he believed in 1986 that Wright Prospecting held assets of $15m to $20m, royalties worth $40m to $60m, and iron ore reserves worth between $20m and $40m.
Julian Wright is expected to testify in the case next week.
Mrs Bennett is also expected to make a rare public appearance later in the matter.