South African billionaire Patrice Motsepe’s net worth has fallen below $3.5 billion after shares of his mining company, African Rainbow Minerals (ARM), dropped sharply on the Johannesburg Stock Exchange (JSE). Investors sold down the stock after the company approved nearly $1 billion in new investments to expand two South African mining operations, pushing the shares to their lowest level in more than a year.

According to Forbes, Motsepe’s fortune declined to about $3.4 billion at the time of publication. The drop reflects the weaker market value of his 43.66 percent stake in ARM, equivalent to 91,133,393 shares. As the company’s share price retreated, ARM’s market capitalization slipped below $2 billion, reducing the value of Motsepe’s holding to roughly $850 million.

Shares tumble after investment announcement

The selloff followed ARM’s announcement on Thursday that it will invest R15.2 billion ($925 million) over the next seven years to expand its Bokoni platinum-group metals (PGM) mine and spend a further R753 million to restart the Nkomati nickel operation. ARM shares fell as much as 9.7 percent during trading before closing 8.07 percent lower on the JSE.

The investment plan marks a major commitment to two assets that have faced operational challenges. ARM placed Bokoni on care and maintenance last year as weak platinum-group metal prices weighed on profitability, recording a R2.2 billion ($131 million) impairment. Under its revised development plan, the company expects to restart the mine in 2028 before increasing processing capacity from 2030.

EV transition reshapes metal demand

Demand for platinum-group metals remains closely tied to the global automotive industry, where the metals are widely used in catalytic converters that reduce emissions from gasoline and diesel vehicles. The faster adoption of electric vehicles, which do not require catalytic converters, has raised questions about long-term demand, although producers continue to point to supply constraints as a supporting factor.

Despite those concerns, ARM said it remains confident about the long-term outlook for platinum-group metals. The company said years of limited investment, declining ore reserves at South African mines and falling production in other key mining regions are expected to tighten global supply over time. Once the Bokoni expansion is completed, ARM expects the operation to add as much as 400,000 ounces of annual platinum-group metals production.

The company is also moving ahead with plans to revive the Nkomati nickel mine. In April, ARM announced a conditional agreement to supply nickel from the operation to a Finnish smelter owned by Boliden AB. While the board has now approved the restart of mining and production at Nkomati, the offtake agreement with Boliden has yet to become unconditional.