The Lloyd's of London insurance market slipped into the red at the full year stage following the most severe hurricane season on record.
For the year to Dec 31 2005, pretax losses were £103m compared to profits a year earlier of £1.37bn.
Net claims were £3.309bn as a result of hurricanes Katrina, Rita and Wilma last year.
Lloyd's chairman Lord Levene, said: "2005 was the worst year on record for natural disasters, costing the insurance industry far more than the impact of the 9/11 attacks on New York."
"For Lloyd's to emerge from such a year with just a small loss represents an excellent performance by the market."
Lloyd's said it has the capacity to write £14.8bn of business this year, an increase of 7% on 2005.
