(ShareCast News) - Lloyd's of London insurer Hiscox posted a jump in gross written premiums for the first nine months of the year on the back of a strong performance in insurance lines, particularly in its US and London markets.For the nine months to the end of September, gross written premiums rose 12.9% to £1.54bn. The company said it also benefited from good risk selection and a lack of storms, floods and hurricanes.Hiscox USA saw gross written premiums up 17.1% to $321.4m, while Hiscox London Market increased gross written premiums by 16.9% £453.4m, driven by a good performance in specialty and casualty.Chief executive Bronek Masojada said: "Our strategy is working. A long-term investment in the brand has helped us attract new business and talent and we see plenty of opportunities for growth."Hiscox said a combination of good underwriting and the wind season ending without incident has resulted in another benign period for the group.Although considerable uncertainty exists around the explosion in the Port of Tianjin, based on early estimates, Hiscox expects net claims of $10m.For the Californian wildfires in September and the more recent South Carolina floods, the company said it has limited exposure.Hiscox UK and Europe has reserved a net €5m for the October floods in the south of France.At 0825 GMT, shares were up 0.3% at 992.00p.