US-based mutual FM Global is to give clients about $US435 million ($427 million) in premium reductions – the biggest such payout by the company.

The reductions will also apply to some Australian clients.

The “membership credit” acknowledges the mutual insurer’s continued success, which it says is partly thanks to policyholders’ “diligent property-loss prevention efforts”.

About 1900 clients globally qualify, with longer-term customers benefitting the most.

The reductions, ranging from 5-15%, will apply when policies are renewed between June 30 this year and June 29 next year.

The scheme was introduced in 2001. The latest payment will bring total membership credits since then to $US2.1 billion ($2.06 billion).

The payment is unique and “testament to the work we put in with clients to reduce losses”, FM Global’s Australian Operations Manager Ian Berg told insuranceNEWS.com.au.

“We had a fantastic year in 2012, despite Superstorm Sandy, and the year to date is looking very good as well,” he said.

“Even though in Australia we are a branch, we still afford the same benefits to our clients as if they were in the US. We are delighted to share our good results with customers.”