Global insurer Ace has more than doubled its annual net profit to $US2.55 billion ($2.9 billion) due to increased underwriting income and a big fall in net realised losses.

A strong fourth quarter contributed to the result, with net profit of $US953 million ($1.08 billion) compared with a slim $US20 million ($23 million) in the previous fourth quarter.

Net written property and casualty premium climbed 9% to $US3.3 billion ($3.7 billion) during the quarter, spurred on by favourable movements in foreign exchange.

Underwriting income for the year improved 17% to $US1.55 billion ($1.76 billion), while a massive reduction in net realised losses from $US1.6 billion ($1.8 billion) to $196 million ($223 million) was another boon for the company.

CEO Evan Greenberg described the property/casualty combined ratio of 88.3% as “a world class result”.

But consumer groups like to point out that 60% of people were properly insured, and say the real problem to emerge is the need for insurers to help their customers fully cover their risks.