Media mogul Sumner Redstone had resigned as CBS executive chairman, a move that comes amid heightened questions about the 92-year-old billionaire’s physical and mental health.
CBS shares were up 3.6 percent in after-market trading, while those of Viacom Inc, where Redstone is also chairman, rose 6.3 percent.
Viacom did not issue a statement on Redstone on Wednesday and could not immediately be reached for comment.
CBS said Redstone would be replaced by Leslie Moonves, the president and chief executive officer of the company.
The Jewish powerbroker’s resignation as executive chairman was effective Feb. 2. But he will stay on as chairman emeritus at CBS.
Redstone’s health has been the subject of intense debate, partly due to his notable absence from the companies’ recent earnings calls. His former girlfriend, Manuela Herzer, had challenged his mental competency in a lawsuit in November.
Redstone controls about 80 percent of the voting shares in Viacom and CBS through a holding company.
CBS said that before electing Moonves, its board offered the position of non-executive chair to his daughter, Shari Redstone, but she had declined.
Viacom said last month it had cut Redstone’s total pay by 85 percent last year in light of his “reduced responsibilities,” without giving further details.