NEW YORK (Bloomberg) — XL Group climbed the most in almost a year in New York trading after the insurer’s second-quarter profit beat analysts’ estimates as premium revenue increased.XL jumped $1.41, or 6.6 percent, to close at $22.78, the biggest gain since last August. The Dublin-based insurer has gained 15 percent since December 31 and is up sixfold from the end of 2008, the year the stock plunged on losses tied to mortgage-market bets.Operating profit in the three months ended June 30 was 71 cents a share, the company said late yesterday in a statement, beating by 16 cents the average estimate of 20 analysts surveyed by Bloomberg. Premium revenue increased 7.3 percent to $1.4 billion. The insurer earned 9.2 cents of underwriting profit for every premium dollar, up from 5.1 cents a year earlier.“We view XL’s second-quarter results as strong, reflecting the company’s ongoing efforts at turning its business around,” Arun Kumar and Brett Gibson, credit analysts at JPMorgan Chase & Co, said in a note yesterday. “Highlights include notably improved underlying underwriting results.”