Zurich Financial Services (ZFS) is expecting to report a net loss of between $200m (£138m) and $400m (£276.9m) for 2001, when it releases full year results on 21 March 2002.
The Swiss company said its performance had been affected by the 11 September attacks, asset impairment charges, lower investment income, higher than expected non-life insurance claims and a deterioration in the results of discontinued operations.
Normalized net income for 2001 is now expected to be between $700m (£483.7m) and $900m (£620.8m).
The company added, barring unforeseeable circumstances, it expected 2002 earnings growth to return to the medium term average of 10% to 15%.
ZFS said it suffered direct insurance losses of $760m (£525.2m) after tax from the September attacks. The attacks also had the indirect impact of lowering life insurance results, asset management fees and interest income by between $200m (£138m) and $250m (£172.5m) after tax.
Realised capital gains are expected to be approximately $2.3bn (£1.6bn) lower than in 2000.