Viacom Inc. executives are pressing ahead with plans to sell a stake in the Paramount Pictures movie studio despite resistance from controlling shareholder Sumner Redstone, potentially inflaming an already incendiary boardroom battle at the media giant.

China’s Dalian Wanda Group Co. is in talks with Viacom about buying 49% of the studio, according to people familiar with the discussions. Another, undisclosed, suitor is also on the hunt for Paramount, one of the people said.

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