Radio, outdoor biz take major write-down.

Stock in Viacom fell 2.5% to $35.28 Thursday following news that the company is taking an $18 billion write-down on the value of its slumping radio and outdoor advertising businesses to comply with new accounting rules.

Viacom posted a fourth-quarter 2004 net loss of $18.4 billion, or $10.99 per share, reflecting the charge. It reported a net loss of $385 million in the same quarter a year ago.

Revenues for the quarter increased 6% to $6.3 billion. Operating loss was $16.7 billion, compared with operating income of $1.1 billion last year.

Revenues for the cable networks business -- home to MTV Networks -- rose 15% to 1.9 billion. Operating income grew 9% to $691 million.

Radio revenues were flat at $550 million, while operating income for the segment swung from a profit of $252 million a year ago to a loss of $10.7 billion in 2004. The radio business incurred a $10.9 billion impairment charge as part of the write-down. Excluding the charge, radio's operating income decreased 9% to $231 million.