Chubb puts its preliminary catastrophe loss estimate for the fourth quarter at $US249 million ($329 million) after tax, including $US215 million ($284 million) from the California wildfires.

Net insured loses from other natural catastrophes are about $US34 million ($45 million), the insurer says.

Chubb posted a $US70 million ($93 million) net loss in the third quarter to September 30.