LONDON (Bloomberg) — Bermuda-based Seadrill Ltd., the Norwegian oil-rig company started by billionaire John Fredriksen, said it had a fourth-quarter net loss after investments slumped.

The loss was $739 million, or $1.86 a share, compared with a profit of $259 million, or 58 cents, a year earlier, the Hamilton, Bermuda-based company said in a statement distributed by Hugin yesterday. It booked a $615 million loss on its investments.

Sales rose to $518 million from $381 million a year earlier, helped by rising rig rates last year as oil prices surged to a record. The price of crude has fallen more than $100 a barrel since peaking at $147 a barrel in July.

"The Board is convinced that the market for offshore drilling units will be strong in the longer term, in particular for the ultra deepwater segment," Seadrill said. "The remaining reserve-life for oil and gas has for the oil companies over the last 10 years been reduced significantly."

Seadrill wrote down the value of holdings in Pride International Inc., Scorpion Offshore Ltd. and SapuraCrest Petroleum Bhd. The company didn't propose a dividend for the fourth quarter.