The Public Investment Corporation has increased its shareholding in mining giant Sibanye-Stillwater from 9.3% to 10%, it was announced on Thursday.
Sibanye, which is listed on the JSE and NYSE, is now the world's largest platinum producer, following its takeover of Lonmin.
The R5.17bn transaction concluded in June.
The company said in a statement it had "received formal notification" that the entity which is managing assets on behalf of public pension funds "has increased its shareholding from 9.397% to 10.031% of the total issued shares of the Company."
The state-owned asset manager, which manages over R2trn in assets, has wide portfolio of investments in listed and non-listed entities. However, some of its investments have come under public scrutiny. President Cyril Ramaphosa last year appointed a commission led by Judge Lex Mpati to look into allegations of misconduct at the PIC.
Sibanye shares were trading nearly 1% up in late afternoon trade JSE, exchanging hands at R26.04.