Viacom Inc. Vice Chairman Shari Redstone may leave the board over a falling out with her father, Chairman Sumner Redstone, a source familiar with the matter said on Thursday.

Viacom shares rose 3.5 percent as her possible departure revived questions over who might succeed the 84-year-old mogul, stoking speculation the company could be sold, one industry analyst said. Viacom owns the MTV Networks and Paramount movie studios.

Shari Redstone, 52, sits on the board of Viacom and CBS Corp. and was viewed as a potential successor to her father.

Shari is still an active and involved member of both the CBS and Viacom boards, Nancy Sterling, a spokeswoman for Shari Redstone said, declining to confirm any negotiations. She has no intention of resigning and has not been asked to resign.

Viacom and CBS representatives were not immediately reachable for comment.

She became vice chairman after her father pushed out then-CEO Mel Karmazin in 2005, a recurring theme in Viacom history. Another CEO, Frank Biondi, left after the chairman sought a more active role in the company he founded from a movie theater chain.

The latest feud comes after Shari Redstone had pushed for executive compensation to be more closely tied to performance, according to a Fortune magazine report published on the CNN Money Web site on Thursday, citing unnamed sources.

Representatives for both sides are negotiating a separation agreement that could include Shari Redstone buying out the family owned theater chain National Amusements to detach from family affairs, The Wall Street Journal reported, citing an unnamed source.

National Amusements controls about 80 percent of Viacom's voting stock.

Sumner Redstone is no stranger to family strife. He settled a messy lawsuit in February with estranged son Brent Redstone in a squabble over his share of the family fortune.

Viacom's class B shares rose $1.45, or 3.49 percent, to $42.68 on the New York Stock Exchange.

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