Bermuda insurer Ironshore's A- (excellent) financial strength rating has been affirmed by ratings agency AM Best.

The company's issuer credit rating was also affirmed at a-. The ratings apply to both Ironshore Insurance and Ironshore Reinsurance.

Best said the ratings reflected Ironshore's solid operating results and excellent capitalisation.

The Bermuda outfit, whose holding company Ironshore Inc. is based in the Cayman Islands, was set up early last year with $1 billion of capital.

It has already expanded into the professional liability, specialty construction and healthcare liability markets, with the creation of its IronPro, IronBuilt and Iron Health divisions.

Best affirmed the ICR of bbb- of Ironshore Inc. The outlook for all ratings is stable.

Best also has assigned an FSR of A- and ICRs of a- to Ironshore Indemnity Inc. (III) (Minneapolis, MN) and Ironshore Specialty Insurance Company (ISIC) (Phoenix, AZ). The outlook assigned to these ratings is stable.

Best stated: "Management continues to enhance infrastructure along with systems and controls to accommodate current and future growth. During its first year, Ironshore focused on property coverage and expanded into professional liability lines as included in its original plan.

"The company, however, was challenged by less than anticipated premium volume due to the current soft market along with some unexpected losses in segments of its investment portfolio.

"Furthermore, Ironshore is still establishing a formal enterprise risk management framework that will address all aspects of its risk exposures."

Best added: "III will provide Ironshore with a US presence in the D&O, E&O and professional indemnity markets, while ISIC was established as an excess and surplus lines writer focusing on contractor, artisan, hospital and long-term care professional liability through its IronBuilt and IronHealth business segments."

Ironshore was susceptible to low frequency high severity eventsand would continue to be challenged by increased competition from both established companies and start-ups seeking market opportunities, Best added.