It was not immediately clear if Moonves would stay on for the duration of the investigation.
The board is split between those loyal to Moonves, who has run the company for more than a decade, and Shari Redstone, whose family owns a controlling stake in CBS.
The sources told CNNMoney that the Monday meeting was scheduled before a bombshell report in the New Yorker Friday detailed allegations against the CEO. "I will stand by that statement today, tomorrow, forever".
Corporate governance experts said there could be several reasons why CBS's board may not want to fire Moonves, including its fiduciary duty to shareholders to minimize the company's legal liabilities. The board on Friday said it would initiate an investigation into the allegations made about Moonves and the culture of CBS...
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On the agenda, sources said, was whether to suspend Moonves, one of the most powerful executives in Hollywood, pending the outcome of the probe. Chen's The Talk co-star Sharon Osbourne questioned "the timing" of the allegations against Moonves as she offered support to the high-profile CBS couple. "I couldn't get him off me", she said.
The revelations come amid a legal battle for control of the USA television giant - between the Redstone family, which controls CBS, and the board, chaired by Moonves.
Early trading shows CBS's shares are down almost 4 percent at around $52.00 at 7:10 am PST after tumbling 6 percent Friday following the release of Ronan Farrow's bombshell expose, in which six women accused Moonves of sexual harassment dating back more than two decades. Viacom shares, conversely, have risen 3 percent during that time on investor expectations that the chances of a merger with CBS have increased.
The board also postponed CBS's annual shareholder meeting, which was previously scheduled to be held August 10.
The directors now plan to use the meeting at least in part to select a special committee that will oversee the investigation.
A CBS move to weaken the Redstone family grip on the company was countered by National Amusements Inc., the Redstone holding firm - and the issue is now before a DE judge. The trial in a DE court is expected to start in October.