The US has had the worst hurricane season since records began

The reinsurance giant said that Wilma and Rita would cost the industry a combined $20bn, after earlier putting a $40bn figure on Katrina.

Swiss Re said the hurricanes would cost it nearly $2bn, and it would miss its earnings growth target for 2005.

Fellow reinsurer Hannover Re also warned about its profits on Wednesday.

The German company said that as a result of Wilma it was cutting its 2005 profit forecast, adding that it would give a more detailed assessment when it reports its third-quarter results on 10 November.

Industry wide

Hannover Re, the world's third-largest reinsurer, has already said that Rita will cost it $180m and Katrina $300m.

The impact from these storms had initially been underestimated, and this is now the payback for that Zurich-based insurance trader

The largest company in the sector, Munich Re, has yet to give details on its Wilma impact, but has already said it faces a combined $782m bill for Katrina and Rita.

Munich Re has said it will only be able to stick to its 2005 profit target by selling its stake in German bank HVB.

Industry analysts said the profit warnings from both Swiss Re and Hannover Re showed that the industry had been worse hit by the hurricanes than previously thought.

"The impact from these storms had initially been underestimated, and this is now the payback for that," said a Zurich-based trader.

This year the southern states of the US have had to weather the worst hurricane season on record.

Katrina struck the US Gulf of Mexico coast in late August, Rita hit Texas and Louisiana in late September, and last month Wilma caused widespread damage in Florida.