Bermuda-based insurer and reinsurer Arch Capital has reported third-quarter net income of $US223.19 million ($253.76 million) – more than double the $US109.34 million ($124.32 million) it made in the corresponding period last year.

The rise was partly due to foreign exchange gains of $US57.49 million ($65.36 million), compared with foreign exchange losses of $US41.36 million ($47.03 million) in the September quarter last year.

Gross written premium for the quarter was $US1.14 billion ($1.3 billion), up 9.8%, while the combined operating ratio deteriorated to 88.5% from 86.1%.

Investment income gained 9.3% to $US72.24 million ($82.13 million).

In the nine months to September 30, Arch’s net income grew 13.3% to $US602.74 million ($685.3 million).