US media giant Viacom will split into two discrete entities earlier than planned. The demerger, originally intended for early 2006, is likely to be completed by the end of this year.

The two new companies, Viacom and CBS Corporation, will be headed respectively by Tom Freston and Leslie Moonves.

The media giant's veteran founder Sumner M Redstone (82) will continue as chairman and controlling shareholder of both entities, while daughter Shari will be installed as non-executive chairwoman.

The split was originally proposed by Redstone senior in the spring as a strategy to boost his empire's flagging share price, down 10% this year after an 18% plummet in 2004.

The company has given no reason for the fast-forwarding of its plans, but industry sources say it is partly due to the enthusiasm with which Freston and Moonves drove the split of their respective operations when they were named co-presidents and co-chief operating officers of Viacom last year.

Data sourced from Wall Street Journal Online; additional content by WARC staff