Arch Capital Group Ltd. has had its financial strength rating raised to A from A- by Standard & Poor's Ratings Services.

The New York-based rating agency raised the ratings of Arch Reinsurance Ltd., Arch Reinsurance Co., Arch Insurance Co., Arch Specialty Insurance Co., Arch Excess & Surplus Insurance Co., and Arch Insurance Co. (Europe) Ltd.

"The upgrade reflects Arch's strong operating performance since inception in absolute and relative terms, its broad and well-diversified business platform, and its strong quantitative and qualitative risk management capabilities, which should help the group mitigate reserve risk associated with its casualty book of business and effectively implement cycle management strategies," said S&P credit analyst Laline Carvalho in a statement announcing the change, Business Insurance reported.