MONTE CARLO (Bloomberg) — Reinsurance rates at companies such as Swiss Reinsurance and Munich Re are likely to drop unless a catastrophe causing more than $25 billion of losses occurs, said Aon Corporation, the world's second-largest insurance broker.

"Without a major catastrophe event in 2007, we are likely to witness reinsurance price decreases worldwide," Aon said in a report released at a reinsurance conference in Monte Carlo. "Pricing trends are indicating that July 2006 renewal pricing represented a peak."

Prices that doubled for some risks after storm-related losses of $58 billion in 2005 are beginning to decline amid increased competition and supply.

In the US, casualty reinsurance rates may retreat 20 percent in 2008, while European casualty reinsurance prices may drop 10 percent, Chicago-based Aon said.