Chubb has reported a third-quarter net profit of $US601 million ($830 million), up from $US594 million ($820.5 million) in the corresponding period last year.

The combined operating ratio for the quarter improved to 83.3%, from 85.8%.

Net written premium was $US3.2 billion ($4.4 billion), unchanged from the corresponding period last year.

For the first nine months of this year, net income fell 5% to $US1.5 billion ($2.1 billion).

The combined operating ratio for the nine months was 87.5%, compared with 89.6% in the corresponding period last year.

Net written premium for the nine months grew 1% to $US9.6 billion ($13.3 billion).

On July 1 Swiss insurer Ace announced it will acquire US-based Chubb for $US28.3 billion ($39.2 billion). The transaction is expected to close in the first quarter of next year.