Bermuda-based PartnerRe’s financial strength rating has been placed under review with negative implications by insurance ratings firm A.M. Best.According to a statement issued today, A.M. Best has placed PartnerRe’s financial strength rating (FSR) of A+ (Superior) and issuer credit ratings (ICR) of “aa-” under review. The ratings firms has also placed under review with negative implications the ICR of “a-” and debt ratings of its parent, PartnerRe Ltd.This rating action follows PartnerRe’s recent pre-earnings release, which provided estimates of losses related to Thailand flooding and its outlook on fourth quarter 2011 financial results.The under review status reflects A.M. Best’s concern with the aggregation of catastrophe losses that PartnerRe has experienced on an absolute and relative basis. The accumulation of catastrophe losses experienced by PartnerRe in 2011 has strained average historical measures.PartnerRe will remain under review pending the completion of A.M. Best’s analysis of the company’s final 2011 earnings release and catastrophe losses as well as market analysis of PartnerRe’s 2011 results relative to its peers. The analysis also will include a review of the company’s capital position, risk appetite and risk management capabilities.