Amlin has reported a net loss after tax of £67m for 2001, compared to a loss of £19m in 2000.
The insurer's World Trade Centre loss is now estimated at £63.9m, which it described as "broadly in line with previous estimates".
The company said it expects to underwrite £1bn of premium income this year.
Chairman Roger Taylor said: "The operating loss of £53.9m for continuing operations, assuming a long term investment return, would have been an operating profit of £10m but for the terrorist atrocities of 11 September.
"Poor Stock Market performance during 2001 once again suppressed our overall investment returns.
"With the high levels of return anticipated from underwriting over the next few years, we have consciously decided to limit our investment risk, to ensure that we do not place in jeopardy the assets we need to support our underwriting in a hard market. It was for this reason that we divested our remaining equity portfolio in September 2001, and reinvested the proceeds in cash."
Taylor added that no dividend would be paid in respect of 2001.
