The Lloyd's of London insurance market has boosted its estimated losses due to September 11 to £1.9bn.
Lloyd's, which had previously estimated it would lose £1.3bn from the disaster, said it had increased its estimate by 45% after new property claims came to light.
It added that its exposure to the disaster through reinsurance contracts had also risen as insurers that had taken out cover with Lloyd's had increased their estimated exposure to the strike.
But the market said it could still cover the revised figure, and added that its total exposure, before reinsurance claims were taken into account, had risen by just 6% to £5.7bn.
Chairman Sax Riley said: "Anyone searching these figures for signs of Lloyd's demise will be disappointed."
He added: "The 40% increase in premium income written for this year, and the steep rate rises that have been seen since September, mean our financial performance is turning the corner rapidly."
Lloyd's said it had written £1.2bn more in total premiums during the first 10 months of this year compared with 2000.
The market, which uses a three-year accounting system in which the financial year does not close until two years after the calendar year ends, now estimates it will make a loss of £1.67bn for 1999, up from its previous projection of a £1.39bn loss.
For 2000 it is expecting losses to be £1.49bn, compared to its previous prediction of a £700m loss.
The 2000 figure includes £650m of World Trade Centre losses, as losses are accounted for in the year in which the policies were issued.