Moody's Investors Service has downgraded the insurance financial strength rating (IFSR) of Stein Insurance Company to A3 from A2. The outlook on the rating is negative. Stein is a Guernsey-based core captive insurance subsidiary of Melbourne firm BHP Billiton, the multinational mining, metals and petroleum company. The rating concludes the review for downgrade initiated on December 24, 2015. The downgrade is driven by the recent downgrade of the issuer ratings of BHP Billiton and BHP Billiton to A3 from A1 on March 3, 2016 with a negative outlook, according to Moody's. The downgrade of BHP Billiton and BHP Billiton reflects the deterioration in the company's earnings and cash flow, which has led to significantly weaker credit metrics.