National Amusements The cornerstone of the empire, the family’s holding company comprises a 1,500-movie-theater chain and controlling voting shares in Viacom and CBS. Sumner owns 80 percent of National Amusements; his daughter, Shari, 20 percent. Redstone sold $233 million worth of stock in Viacom and CBS to help pay off National Amusements’ $1.6 billion in debt.

CBS The network has buoyed itself with the success of the CSI franchise and has broadcast rights to the Grammy Awards show for 2009. CBS, a National Amusements holding, has been vying for the No. 1 network spot. As of mid-November, CBS’s stock was down more than 70 percent for the year.

Midway Games Redstone sold his controlling stake in this videogame maker for $100,000 to a private investor in December. Redstone’s 87 percent stake in the company was an estimated $800 million investment whose market value had fallen 97 percent in the past three years. Midway was famous for creating the Mortal Kombat franchise.

WMS Industries Formerly the world’s largest manufacturer of pinball machines, WMS retooled 10 years ago and has become a leading seller of casino gaming machines. Some suspect that Redstone might sell his stake in the company for some quick cash, but in 2008, WMS saw a 38 percent jump in profit over 2007.

Viacom As of December, shares were down about 65 percent from the previous year, compared with a 46 percent decrease in the Standard & Poor’s media index during the same period. Viacom, controlled by ­National Amusements, includes MTV, Comedy Central, and Nickelodeon, as well as Paramount Pictures.