Andrew Forrest is $2.7 billion richer after the iron ore price rose to a seven-year high, while Chris Ellison's stake in Mineral Resources has grown by $53.4 million.
Iron ore reached about $US136 per tonne yesterday, its highest price since November 2013.
It comes after Brazilian iron ore major Vale revealed it would miss its production target of at least 310 million tonnes for the full calendar year, having estimated 300-305mt.
The announcement means more opportunity for Australian producers, which are already benefiting from strong demand for the steelmaking metal in China despite tension between the two countries.
Shares in Forrest-chaired Fortescue Metals Group surged on the news to a record high of $20.65 – closing up 13 per cent at 3:00pm AEDT.
It means Mr Forrest's stake in the company has grown to more than $23 billion.
MinRes managing director Mr Ellison's stake in the company has grown to nearly $760 million.
Fortescue, MinRes and Mount Gibson are WA’s biggest ASX-listed iron ore miners by revenue, according to Business News Data & Insights.
Fortescue generated $18.8 billion in revenue in the year to June 30, MinRes $3.4 billion and Mount Gibson $463 million.
Elizabeth Gaines-led Fortescue has had a solid start to the current financial year, having already shipped 44.3mt of iron ore – up 5 per cent on the first quarter of FY20.
The company expects to ship between 175mt and 180mt in FY21.
Meanwhile, Vale anticipates its 2021 output to be 315-335mt, less than what analysts have predicted.