US reinsurer earnings grew in the first half of this year thanks to fewer natural catastrophes and an improved investment environment, industry figures show.

Net income for the six months to June 30 totalled $US4.76 billion ($5.15 billion) for 18 companies featured in a report by the Reinsurance Association of America.

The figure compares with $US3.71 billion ($4.01 billion) for 19 companies in the corresponding period last year.

In the first half of last year reinsurers were affected by a large number of natural catastrophes, including floods and bushfires in Australia, while the investment environment was not as “robust”, the association says.

“In short, this has been a better year with respect to natural catastrophes and… investment returns for companies have also improved,” a spokesman told insuranceNEWS.com.au.

The combined ratio improved to 86% from 91.5%. Gross written premium was $US21.26 billion ($22.99 billion) in the first half, while net investment income totalled $US4.3 billion ($4.65 billion) and the net underwriting gain was $US1.71 billion ($1.85 billion).