RenaissanceRe Holdings Ltd has reported a $24.8 million profit in the second quarter - an 88-percent drop over the same period in 2010.Net income was $210.2 million or $3.66 per share in the second quarter of last year.The Bermuda reinsurer said it suffered losses of $70.8 million related to the deadly US tornadoes this year.Book value per common share increased 29 cents, or 0.5 percent, in the second quarter of 2011 to $57.30, compared to a 5.8 percent increase in the second quarter of 2010.Renaissance Re CEO Neill Currie said: “Our results for the quarter were impacted by $70.8 million of net losses from the tornado activity in the US. As a result, we reported $24.8 million of net income, a $10.2 million operating loss and a 0.5 percent increase in book value per share in the quarter.”He continued: “At the same time, we had a successful June 1 renewal season and are pleased with our portfolio of risks, which reflects improving market conditions in our reinsurance segment. Our strong balance sheet, high ratings and leadership position in property catastrophe reinsurance allowed us to increase our catastrophe premiums by over 15 percent.”The reinsurer said gross preThe reinsurer said gross premiums written increased $135 million, or 26.7 percent, to $641.6 million, primarily driven by improving market conditions in its core markets experienced during the June 2011 renewals and $22.5 million of reinstatement premiums written from the large US tornadoes in the second quarter of 2011.Excluding the impact of $22.5 million of reinstatement premiums written in the second quarter of 2011, gross premiums written increased $112.5 million, or 22.2 percent.