Arch Capital Group has recorded a substantial increase in reinsurance income for the nine months to September 30.

Reinsurance gross written premium (GWP) grew 13% to $US1.17 billion ($1.23 billion) and underwriting income was up 18% to $US279.67 million ($294.74 million).

GWP from the insurance division increased 2% to $US2.08 billion ($2.19 billion), while its underwriting profit was $US43.75 million ($46.1 million), compared with a loss in the corresponding period last year.

The group’s net profit was $US531.79 million ($560.45 million), down 2% from the corresponding period last year, when the result was boosted by investment gains and a lower tax bill.

Overall GWP grew 6% to $US3.24 billion ($3.41 billion) for the nine months, and the combined ratio was 86%, an improvement from 89.2%.