Lloyd's Syndicate 609 (UK), managed by Atrium Underwriters Ltd., owned by Bermuda company Ariel Holdings, has had its syndicate rating of A (excellent) and issuer credit rating (ICR) of A+ affirmed by AM Best Co.

The outlook on both ratings has been revised to stable from positive, reflecting the stable outlook on the rating of Lloyd's of London.

The ratings reflect AM Best's view that syndicate 609 is likely to benefit from financial flexibility provided by Ariel, which acquired Atrium Underwriting plc. in August 2007.

Meanwhile, the ratings agency has affirmed the Best's Syndicate Rating of A (excellent) and issuer credit rating (ICR) of a+ of Lloyd's Syndicate 570 (UK), which is also managed by Atrium Underwriters Ltd. The outlook on both ratings has been revised to stable from positive, reflecting the stable outlook on the rating of Lloyd's of London.

AM Best believes Ariel's expertise in certain lines of business, particularly property catastrophe business, is expected to assist both the AUL managed syndicates, while the ratings also reflect the syndicate's excellent expected open year performance and specialist business profile, in addition to the underlying strength of the Lloyd's market.

AM Best believes that syndicate 609's strong performance record is likely to be sustained in 2008 and further ahead, supported by a smooth transition in the syndicate's leadership following the 2007 decision of the active underwriter to step down from this role from January 2008.

Nevertheless, the syndicate's performance will continue to be exposed to major events through its underwriting in the marine, energy and aviation sectors, as well as from its property catastrophe account, it added.

The syndicate is likely to return an excellent profit on capacity of approximately 8.5 percent to 18.5 percent for the 2006 year of account, in line with its September 2007 quarterly return, reflecting a significant strengthening in rating conditions in catastrophe-exposed energy and property lines of business.

AM Best believes that the 2005 year of account is likely to close with an excellent return on capacity above the mid-point of the syndicate's published range of zero to five percent, taking into account its exposure to both US property catastrophe business and energy business written in the Gulf of Mexico.