Beazley's gross premiums written increased by 6% to $1,762m in the nine months to the end of September but premium rates on renewal business decreased by 1%.
The group also reported a year to date investment return of 2.4%.
Chief executive Andrew Horton said: '"The third quarter of 2017 was defined by the high frequency and severity of natural catastrophes.
'Beazley is in the catastrophe insurance business and paying natural catastrophe claims is part of what we do.
'Our focus is currently on providing the support and resources necessary to help our policyholders recover as quickly as possible.
'These events will naturally affect our full year results but our diverse underwriting portfolio continues to serve us well.
'We also expect to see rate increases across some lines of business in the coming months.'