The rating on Mitsui Sumitomo Insurance Co. Ltd. (MSI) reflects the company's excellent market position, and its solid financial profile characterized by its extremely strong capitalization and superior underwriting performance. Moderating factors include its lackluster investment income under persistent ultra-low interest rates, a weak domestic stock market, and the competitive environment in the Japanese non-life market with stagnant growth prospects. MSI was formed through a merger of Mitsui Marine&Fire Insurance Co. Ltd. and Sumitomo Marine&Fire Insurance Co. Ltd. on Oct. 1, 2001. Excellent business position. MSI currently enjoys a very strong market position as one of the largest non-life insurer in Japan with approximately 17.3% market share in net premiums written in fiscal 2001 (ended March