Sumner Redstone, the chairman of Viacom, sold the majority of his Class B shares in the company, according to a regulatory filing on Monday.
Redstone sold 128,777 common Class B shares for about $7.5 million on February 7. He still controls Viacom through National Amusements and its 79 percent stake of Viacom Class A shares.
Viacom's Class B shares do not have voting rights.
Viacom owns the cable channels such as MTV and Nickelodeon along with the movie studio Paramount Pictures.
In January, Redstone, who is 89, donated $10 million to the University of Southern California's School of Cinematic Arts.
In the past year, Viacom has been struggling with declining cable ratings and is trying to gain a steadier foothold with its programming.
Viacom shares closed 3 cents higher at $59.31 on Monday.
(Reporting By Jennifer Saba in New York; Editing by Leslie Adler)