Bermudian-based XL Group beat analysts' estimates for second-quarter earnings, but profits were hit by catastrophe losses and expenses related to its integration with Catlin Group.The company, which this month completed its redomestication to the island from Ireland, said operating income from the April-through-June period totalled $106.4 million, or 37 cents per share, compared to the 23 cents per share consensus forecast of Wall Street analysts.This was down from $245.8 million in the same period last year. The company said the decrease was driven by $52.1 million in integration costs and $240.1 million in catastrophe losses.“XL Catlin's second-quarter results were significantly impacted by global catastrophes, reducing operating earnings per share by 84 cents,” XL's chief executive officer Mike McGavick said.“In the face of these events and challenging markets, we demonstrated progress in our underlying performance.“We generated gross premiums written of $3.6 billion, P&C underwriting profit of $102 million, and an accident-year, ex-catastrophe P&C combined ratio of 90.3 per cent. The benefits of our integration are emerging and we are committed to the hard work and execution required to succeed.”The company, which markets itself as XL Catlin, recorded a combined ratio - the proportion of premium dollars spent on claims and expenses - of 96 per cent in the second quarter compared to 89.9 per cent in the corresponding period of last year.Net income was $43.8 million. This includes the impact of the Greycastle Life retro arrangements.Annualised operating return on equity on a year-to-date basis was 3.6 per cent, when unrealised investment gains and losses are included, or 5.1 per cent when integration costs are excluded.The company wrote more business, with property and casualty gross premiums increasing 17.6 per cent compared to the prior year quarter as a result of the combination with Catlin.Net investment income for the quarter was $215.4 million, compared to $223.2 million in the prior-year quarter and $205.9 million in the first quarter of 2016.Share buybacks totalled 9.7 million shares, or $328.3 million, during the quarter, At June 30, 2016, $815.8 million of ordinary shares remained available for purchase under XL's share buyback programme.