Reinsurance Co. Ltd. The agency has placed the "A'' (Excellent) ratings of Winterthur Reinsurance Corp. of American, Winterthur Life Reinsurance Co., and SAFR Reinsurance Corp. of the US under review "with developing implications''.

The news follows PartnerRe Ltd.'s announcement that it will acquire the reinsurance operations of the Winterthur Group for about $750 million.

"Following the transaction, A.M. Best believes Partner Reinsurance Co. Ltd.

will continue to maintain strong financial flexibility and superior capitalisation and will comfortably support its superior rating,'' the agency stated in a press release.

A.M. Best expects the purchase to strengthen PartnerRe's presence in the US and is "consistent with its diversification strategies''.

Earlier this week Standard & Poor's (S&P) affirmed its double "A'' financial strength and counterparty credit ratings on the PartnerRe.