US-based Liberty Mutual Holding Company has reported net profit of $US530 million ($724 million) for the six months to June 30, down 19.2% on the corresponding period last year.

David Long, CEO of subsidiary Liberty Mutual Insurance, says earnings were hit by currency volatility, increased catastrophe losses and market pressure in the energy sector.

The holding company’s pre-tax operating profit for the half-year was even less encouraging, down 41% to $US724 million ($989 million).

Revenue totalled $US20.06 billion ($27.41 billion), up 2.3%.

Net written premium grew 6.4% to $US19.13 billion ($26.14 billion), reflecting “the continued strength of our underlying operations”, Mr Long says.

Catastrophe losses for the six months totalled $US1.3 billion ($1.8 billion), up 11.5%.

The combined operating ratio was 99.8%.