The Bermudian captives of the world's largest offshore drilling company and a premier oilfield services provider have maintained excellent credit ratings with AM Best.

The ratings agency affirmed the financial strength rating of A (Excellent) and the long-term Issuer credit ratings of “a+” (Excellent) of Castle Harbour Insurance Ltd and Harrington Sound Insurance Ltd. The outlook of these ratings is stable.

These companies are captive insurance companies of SLB NV, a global technology company that provides services to the energy industry.

Formerly known as Schlumberger Ltd, the Houston, Texas headquartered company is incorporated in Curaçao and changed its legal name to SLB NV last month.

The multinational oilfield services company has a footprint in more than 100 countries and employs approximately 110,000 people. It is also the world's largest offshore drilling contractor by revenue.

The ratings of Castle Harbour and Harrington reflect the companies’ balance sheet strength, which AM Best assesses as strongest, as well as their strong operating performance, neutral business profile and appropriate enterprise risk management.

Castle Harbour and Harrington maintain the strongest level of risk-adjusted capitalisation, as measured by Best’s Capital Adequacy Ratio, in addition to displaying excellent liquidity measures.

The operating performance assessments of strong, reflect the companies’ favourable underwriting results driven by excellent loss history and benefiting from inherently low expense structures as single-parent captives. The ratings also take into consideration the captives’ strategic importance in providing tailored insurance coverages for the parent and its subsidiaries.

While each captive carries relatively large limits within its respective designated coverages for the parent in the general liability and property lines of business, each writes a broad scope of business and has considerable geographic diversification.

Each captive also maintains significant retentions within the offered limits, but they are readily manageable within their respective capital bases and organic surplus growth, offset by periodic sizeable dividends.

As captive insurers of SLB, the companies are an integral part of the parent’s ERM framework, which includes defined risk controls and optimisation of the captives’ capital.

AM Best also recognises the financial flexibility afforded by their parent company, and their strategic importance across SLB.