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Implats said Abax Investments, Allan Gray Ltd., Coronation Asset Management Ltd., MandG Investment Managers and Ninety One SA Ltd. have already sold their shares to the company. RBPlat surged 14% to 138.33 rand as of 1:28 p.m. in Johannesburg.

Implats said its offer — a 24% premium to RBPlat’s closing price on Nov. 26 — provided “compelling value” for shareholders. The offer will open in mid-January for 30 days, and could be extended for another 15 days, said Kirthanya Pillay, the company’s group executive for corporate development.

Muller said Northam was unlikely to follow up with a general offer immediately, following its purchase of the stake owned by Royal Bafokeng Holdings — the investment arm of the Bafokeng nation that’s led by King Kgosi Leruo Molotlegi and his advisers.

“There is a clear indication 180 rand a share it offered to RBH is probably not repeatable,” said Muller, adding that he doesn’t expect Northam to sell its stake. The CEO said having Northam as a shareholder in RBPlat is an advantage because of the company’s “strong operational track record.”

Leon Van Schalkwyk, a spokesman for Northam, didn’t immediately respond to calls seeking comment. Northam’s audacious bid for the RBH shares reflected the growth ambitions of CEO Paul Dunne. Northam has an option to raise its stake in RBPlat to 36%, and earlier this month said that holding could provide a platform for a possible combination of the two miners in the medium term.

RBPlat said in a separate statement it has appointed PSG Capital Ltd. as an independent expert to assess the Implats offer.