(Bloomberg) ? Aon Corp., the world?s second-biggest insurance broker, said losses from natural catastrophes in the US, Japan and the Caribbean last year slowed a decline in insurance premium rates.

The US storms will ?reduce the scale of the reductions that otherwise would have applied,? said Charlie Cantlay, deputy chairman of Chicago-based Aon?s reinsurance division, at a briefing in London. The tsunami that struck Asia on December 26 will have little effect on rates, he said.

Insurers face losses of as much as $42 billion from natural disasters, including four US hurricanes and ten typhoons in the Pacific Ocean last year, making the period one of the most costly on record, the Insurance Information Institute in New York said on December 27. Insured losses from the Asian tsunami may be as much as $5 billion, Cantlay said yesterday.