Ace Ltd. posted year-to-date net income of $1.94 billion, a 141% increase over the $805 million in net income the Zurich-based insurer and reinsurer tallied for the first nine months of 2011.

Net written premium for the first nine months of 2012 was $12.42 billion, compared with $11.74 billion of net written premium during the same period a year ago, Ace reported Tuesday. The company’s combined ratio for the first nine months of 2012 was 90.2%, an improvement over the 95.3% combined ratio the company tallied in the same period during 2011.

On a quarterly basis, Ace posted third-quarter earnings of $640 million, compared to a net loss of $39 million in the same period in 2011.

The company’s net written premiums increased to $4.72 billion for the quarter, an 8.6% increase compared to the $4.34 billion in net premiums the company recorded in the same period a year ago. However, the Ace’s combined ratio for its property/casualty lines deteriorated slightly in the quarter to 92.0%, compared with a combined ratio of 90.2% in the third quarter last year.

The company said its overall underwriting performance was stung by losses in its crop insurance business as drought conditions in the U.S. led to a 114% combined ratio for its crop insurance line for the quarter.

“While the drought conditions in the U.S. severely impacted our crop insurance business and reduced operating income by 28 cents per share, as a total company we delivered outstanding underwriting results as demonstrated by a P&C combined ratio of 92% and produced an operating ROE of 11.5%,” Ace Chairman and CEO Evan G. Greenberg said in a statement. “We continue to benefit from the favorable P&C pricing trend in North America, where we recorded strong double-digit premium growth, and internationally, excluding the impact of foreign exchange, we also registered good growth across a broad spectrum of property and casualty, accident and health, and personal lines businesses, particularly in Asia and Latin America.”