Bermuda reinsurer RenaissanceRe Holdings Ltd.'s net income almost doubled year on year in the second quarter to $271.2 million, boosted by increased revenue.

The Class of 1993 reinsurer also benefited from $106 million in favourable prior years' development on reserves, which means the company set aside more than it thought it needed to meet claims from past events.

These reductions in estimated ultimate losses related to catastrophes including hurricanes Gustav and Ike (2008), the UK flooding (2007) and European windstorm Kyrill (2007).

Gross premiums written for the second quarter of 2009 increased $47.6 million, or 5.9 percent, to $855.2 million, compared to $807.6 million for the same period last year.

The increase was primarily due to a $67.8 million increase in gross premiums written in the company's reinsurance segment.

RenRe generated $213.6 million of underwriting income and achieved a combined ratio of 43.8 percent in the second quarter of 2009, compared to $175.2 million of underwriting income and a 53.5 percent combined ratio in the second quarter of 2008.

The company's underwriting results for the second quarter of 2009 were primarily driven by lower net claims and claim expenses incurred principally due to $106.2 million of favorable development on prior year reserves.

The net income broke down to $4.32 per share, compared to $135.7 million, or $2.13 per share for the same quarter of 2008. RenRe reported an annualised return on average common equity of 41.5 percent, compared to 19.9 percent in the second quarter of 2008.

Book value per common share increased to $44.17 at June 30, 2009, an 11.4 percent increase in the second quarter of 2009, compared to a 2.8 percent increase in the second quarter of 2008.

"I am pleased to report a strong quarter with an annualised operating ROE of 39 percent and over 11 percent growth in book value per share in the quarter.

"We generated strong underwriting profits and had a successful June 1 renewal season. We are pleased with our portfolio of risks, which reflects improving market conditions in our reinsurance segment, and our investment results benefited from spreads tightening and improving valuations during the quarter.

"With our strong balance sheet, liquidity and market position, we were able to increase capacity for our clients in Florida, both via organic growth of our already strong portfolio and by the successful execution of our newest joint venture, Timicuan Reinsurance II Ltd.

"We also launched our Lloyd's syndicate, RenaissanceRe Syndicate 1458, and announced an agreement to acquire Spectrum Partners Ltd, its managing agency."