Not so. State ownership is not necessary under SA law.
Since the 1920s legislation permits the establishment of public utilities that are not for profit, do not have shares, and are not State-owned or owned by anyone but themselves. Their surpluses ("profits") are only used internally to improve their utility and never distributed externally.
This was the status of Escom/Evkom (before it was renamed Eskom in 1987). Many a blustery interventionist Nat minister had to be told in blunt terms (often by a senior relative of mine, on the Escom board) that the state did not own Escom and to butt out and quit reckless prattle - Escom owned itself in terms of the public utility act, and did not have a shareholder or owner such as the state. Though the president appointed the GM, always as proposed by the General Board, Escom/Evkom ab initio and for decades raised its own finance on local and intl capital markets, was self-funding and never took a cent of taxpayer money until it was nationalised.
Rather laughably and embarrassingly, the ANC didn't fully appreciate this fact for several years, which is why their 1994-9 plans to split Eskom into 9 REDs (regional leccy distis) and REGs (regional leccy generators) came to nought. Eskom was finally nationalised by the ANC through the Eskom Conversion Act 13 of 2001, which converted it from a public utility without shares (and hence no owner) to a company with shares, with all shares owned by the state.