Could CBS, Viacom merge again?

The firms’ contrasting trajectories prompt speculation about Redstone’s plans.

Sumner Redstone had his reasons when he split his media empire into two separate corporations a decade ago: He had two strong top executives whom he wanted to keep happy, and more than enough successful businesses to go around.

Since then, network chief Leslie Moonves has been running the stalwart CBS Corp., which boasts the nation’s most watched TV network. Viacom, meanwhile, has seen its stock plummet more than 45% in the last two years, and its chairman and chief executive, Philippe Dauman, is on increasingly shaky ground.

The contrasting trajectories of the two companies, and Dauman’s precarious position, has prompted speculation about whether the Redstone family might eventually put CBS and Viacom back together again. That would allow them to hand the combined entity to Moonves, 66, who has long wanted to run a major movie studio.

“It’s clear that Les Moonves knows what he is doing while the people running Viacom are stumbling around in the dark,” said Jonathan Taplin, a USC Annenberg School communications professor.

The pitched battle between Viacom and the Redstone family — which controls 80% of the voting shares of Viacom and CBS — intensified Friday amid speculation about Dauman’s uncertain future.

Last week, Redstone ousted Dauman and another Viacom board member from the trust that will eventually oversee his controlling shares in the companies. On Monday, Dauman and George Abrams sued, claiming that Redstone is being manipulated by his daughter, Shari Redstone. That put