Beazley, which provides risk insurance and reinsurance products, reported an 11 per cent increase in gross written premiums to 518m dollars in the first quarter.The company said the first three months were driven by a 24% jump in premiums in the marine division. The unit was supported by growth in the marine liability book and by the new aviation team that started writing business in the fourth quarter. Life, accident and health also rose 24% to $36m.Premiums in the reinsurance division grew 20% to $91m, largely thanks to the catastrophe book and investments in growing its team.In specialty lines an 8% increase to $185m was bolstered by improvements in management liability and in the technology and media business. Property remained unchanged at $84m as did political risk and contingency, which came to $29m..Rates increased by 2.0% across the portfolio. "We have made a positive start to 2013 with an 11% increase in premium and rates rising across most of our business," Chief Executive Officer, Andrew Horton, said.The level of claims notifications during the first quarter was in line with expectations. Investment income for the quarter came to $26.3m. The annualised investment return for the period was 2.6% compared to 1.9% the previous year.During the period, Beazley acquired £26m of its subordinated debt issued in 2006 through its offer in February, leaving £76m of this debt in issue. Shares climbed 1.28% to 229.40 at 09:52 Thursday.RD