Standard & Poor’s has assigned Berkshire Hathaway Specialty Insurance Co. a “AA+” long-term counterparty credit and financial strength rating with a stable outlook.

S&P said it views BHSI as a key component of Berkshire Hathaway Inc.’s strategy to increase its market presence in the primary commercial-lines business and cited the unit’s experienced management team, low operating expenses, strong capitalization and the Berkshire brand as competitive advantages.

S&P said it would consider lowering the ratings if there is a deterioration in capital adequacy or earnings.

BHSI was created in 2013 to write specialty commercial lines on both an admitted and nonadmitted basis.