Bermuda-based Catlin Group Ltd. said it wrote nine percent more re/insurance business through the first nine months of this year.

Catlin's Bermuda underwriting platform made a significantly increased contribution, as its gross premiums written climbed 23 percent to $484 million, compared to $392 million in the same period of 2009.

In its interim management statement, released on Friday, Catlin said the group's total gross written premiums were $3.28 billion in the nine months to September 30, compared with $3.01 billion a year earlier.

Although Catlin is domiciled in Bermuda, its roots and its main sales unit are in the Lloyd's of London market, where it is the third largest insurer by market value.

The latest results show the increasing importance of units based outside London.

Premiums written in North America, Bermuda, Premiums written in North America, Bermuda,Asia and Europe climbed 29 percent to $1.4 billion in the first nine months, compared with a two percent decline in London.

"Our Bermuda, US and international underwriting hubs continue to report meaningful and profitable premium growth, with the non-London hubs now accounting for 43 percent of the group's total gross premiums written," chief executive officer Stephen Catlin said in the statement.

Catlin's biggest increase in business was in property lines, in which premium grew 26 percent, while reinsurance grew 14 percent.

Catlin's international expansion includes the opening of a reinsurance division in Switzerland in an attempt to increase sales in Europe.

Catlin's premium rates dropped 0.5 percent across the group in the nine months, it said. That compared with a six percent increase in the same period a year earlier.

US property and casualty rates this year fell to their lowest in 10 years, according to the Council of Insurance Agents and Brokers. Insurers' excess capital reserves, built up after 2009's rally in equity markets and two years of relatively few costly natural catastrophes, are prompting more competition among firms, causing premium rates to fall.

A prolonged period of low interest rates is also making it more difficult for insurers to generate returns from investments. Catlin said it had managed a 2.9 percent return from its investment portfolio for the first nine months of the year.

Catlin said its estimate for combined losses from the Deepwater Horizon oil rig explosion and the Chile earthquake remained unchanged at $180 million.

Mr. Catlin added: "Investment performance has been satisfactory in an uncertain economic environment.

"While the rating environment is also challenging, we believe there are still good margins available for many classes of business.

"We look forward with confidence, especially with regard to the continued profitable growth of our underwriting hubs outside London, including the development of Catlin Re Switzerland."