Liberty Mutual’s net income for the first six months of 2012 more than doubled, despite more catastrophe losses.

The group’s net income rose 223% to $US598 million ($571 million), compared with the first six months of last year.

Net income for the June quarter rose to $US139 million ($133 million), compared with a loss of $US179 million ($171 million) in the corresponding period last year.

Catastrophe losses fell 48.5% to $US651 million ($622 million) this quarter and dropped 47.5% to $US972 million ($928 million) in the six months to June.

“Profitability improved significantly in the quarter despite catastrophe losses continuing to run at an elevated level,” CEO David Long said.

“Second-quarter premium growth of 8% was driven by continued momentum in US personal lines, rate increases in US commercial lines and robust international results despite significant strengthening of the dollar.”

The combined ratio fell 6.6 points to 105.9% in the quarter and decreased 4.1 points to 103.4% for the half-year.