NEW YORK (Bloomberg) - Ace Ltd, the Swiss insurer operating in more than 50 countries, gained the most since February after profit beat analysts’ estimates and the company boosted its earnings forecast for 2011.Ace advanced $2.08, or 3.2 percent, to $67.96 at 9.36am in New York Stock Exchange composite trading. The Zurich-based insurer climbed 5.8 percent this year through Tuesday, compared with a 1.4 percent drop in the 75-company Bloomberg World Insurance Index.Second-quarter operating profit was $2.01 a share, beating the $1.65 average estimate of 19 analysts surveyed by Bloomberg. Premium revenue advanced on gains in Asia life insurance and its crop-protection business, which the company bolstered through acquisitions. Ace reported lower second-quarter catastrophe losses than rivals Travelers Cos and Chubb Corp., which depend more on US home insurance.Ace is “well diversified, both geographically and by line of business,” said Alan Zimmermann, an analyst at Macquarie Group Ltd, in a note to investors on Tuesday.The insurer raised its forecast on operating profit for the year to a range of $6.00 to $6.20 a share from its projection of $5.40 to $5.70 a share at the end of the first quarter.Premium revenue climbed 16 percent from last year’s second quarter to about $3.76 billion. Excluding the effect of currency fluctuations, the figure increased 12 percent. Ace earned 7.4 cents for every dollar it collected in premiums for the quarter, compared with 10.3 cents a year earlier.“Given our second-quarter results and our momentum that is frankly exceeding both the industry and our own plans, we are quite bullish about the second half of the year,” Ace chairman and CEO Evan Greenberg said during a conference call with investors today.Second-quarter net income fell 10 percent to $607 million, or $1.77 a share. Natural disasters cost Ace $134 million in the quarter, compared with $81 million in the same period last year.