Rupert Murdoch

Rupert Murdoch's 21st Century Fox said on Wednesday it had offered to buy Time Warner, a move that would unite two of the world's most powerful media conglomerates, but Time Warner rebuffed its offer.

Time Warner's stock jumped nearly 20 percent on the New York Stock Exchange after news that Murdoch had his sights on Time Warner, the owner of the Warner Bros. movie studio and cable channels such as HBO and CNN, among other media properties.