Arch Capital Group says second-quarter profit grew 18% to $US202.5 million ($217.3 million), driven by lower catastrophes and gains in underwriting income from casualty, travel, accident and health specialty lines.

The Bermuda-based group’s gross written premium (GWP) increased 8% to $US1.25 billion ($1.34 billion) in the three months to June 30, and underwriting income nearly tripled to $US34.42 million ($36.93 million).

GWP from the insurance division grew 21.1% to $US852.23 million ($914.55 million), while GWP from reinsurance gained 9.7% to $349.84 million ($375.41 million).

The reinsurance division’s net written premium increased just 0.2% to $290.84 million ($312.1 million).

The group’s combined operating ratio was 86.2%, improving slightly from 87.4% in the corresponding period last year.