US-based insurer Liberty Mutual has reported an 85% increase in half-year net profit to $US535 million ($583 million), which the company attributes to the benefits of its global diversity.

Total revenue for the six months to June 30 was $US16.26 billion ($17.71 billion), a 7% increase on the previous corresponding period, while net written premium was 4% higher at $US14.49 billion ($15.79 billion).

Significant natural catastrophe activity had a clear impact on underwriting profitability, with the combined ratio deteriorating 3.6 percentage points to 103.5%.

“Our operating results reflect the benefits of our diversified and global operating model, and our commitment to disciplined underwriting and reserving in order to maintain balance sheet strength,” Liberty CEO Edmund Kelly said.