The combined operating ratio of US reinsurers took a beating in the first half of 2011, jumping to 116.2% for the six months to June 30, according to a survey of 19 US reinsurers by the Reinsurance Association of America.

This compares to the group posting a collective combined operating ratio of 98.7% for the same period last year.

Total net written premium for the group increased 12% for the half to $US13.8 billion ($12.9 billion) up from $US12.3 billion ($11.5 billion) in the first half last year.

But due to the catastrophe losses, combined net income more than halved to $US1.7 billion ($1.6 billion), down from $US4.2 billion ($3.9 billion) in 2010.