XL Group reported a first-quarter profit nearly double that of a year ago on improved underwriting results and higher affiliate earnings.The company posted a profit of $350.8 million last night or $1.17 a share. That’s nearly double the $176.6 million net income it reported for the first quarter of 2012.Operating income was $279.9 million, or 93 cents a share, compared with a prior-year operating income of $165.2 million.Results were better than Wall Street expectations. The 17 analysts polled by Yahoo Finance predicted an operating income of 65 cents a share.XL CEO Mike McGavick said he’s very pleased with the company’s first quarter results."In the first quarter, XL once again delivered solid results — the kind of results we seek to routinely produce,” Mr McGavick said.“While none of us are ready to declare victory, particularly with the benefit of a quiet catastrophe and large loss quarter, such results make us all the more driven to deliver consistent, quality performance, even as catastrophes and losses normalise. We are pleased with our progress and are maintaining our diligent, grinding work."Gross premiums written increased 3.8 percent to $2.4 billion. The company says gross premiums written in the company’s insurance segment were up 12.1 percent from the year prior as a result of new business initiatives in North American programs and construction lines combined with increased policy retentions and moderate pricing improvements across most lines.Gross premiums written for the reinsurance segment however, fell 7.5 percent primarily, the company said, from International due to the non-renewal of certain Marine exposures as a result of the re-underwriting of this line.In the first quarter, XL’s combined ratio — the percentage of premiums paid out on losses and expenses — improved to 87.7 percent from 95.3 percent in Q1 2012.Net investment income fell in the first quarter to $246.5 million, from $265.2 million in the prior year quarter and $245.0 million in the fourth quarter of 2012. The decline against the prior year quarter was primarily due to lower yields as a result of lower reinvestment rates.Fully diluted tangible book value per ordinary share increased by 70 cents from the prior quarter driven by net income growth combined with the benefit of share buy-backs, partially offset by net unrealised losses on investments.During the quarter, XL purchased 8.0 million shares for $223.3 million at an average price of $27.89 per share. At March 31, 2013, $725.0 million of shares remained available for purchase under the company’s previously announced $850 million share buy-back programme.