Arch Capital Group recorded a 34.2% increase in net income to $US233.24 million ($315 million) in the second quarter, driven by gains in its insurance and reinsurance businesses.

Overall gross written premium (GWP) grew 5.4% to $US1.7 billion ($2.3 billion) and the combined operating ratio improved to 82.7% from 84.6%.

Insurance GWP increased 3.4% to $US769.37 million ($1.04 billion) and the business returned to the black with an underwriting profit of $US5.63 million ($7.63 million), after a $US4.5 million ($6.1 million) deficit in the corresponding period last year. The combined operating ratio strengthened to 99% from 100.8%.

Reinsurance GWP increased 8.2% to $US490.33 million ($661.4 million) and underwriting profit gained 28.8% to $US24.41 million ($32.9 million). The combined operating ratio improved to 92.8% from 94%.