US-based insurer Chubb has reported third-quarter net income of $US533 million ($515 million), up 78% from $US298 million ($287.94 million) in the corresponding period last year.

The improvement was driven by lower catastrophe losses, down to $US17 million ($16.42 million) from $US420 million ($405.82 million). The combined loss and expense ratio was 86.3%, compared with 102.6%.

Net written premium rose 1% to $US2.9 billion ($2.8 billion) in the quarter. US premium income grew 4%, while the figure fell 6% outside the US.