is a Japanese insurance holding company headquartered in Tokyo, Japan. MSIG was formed in 2001 from the merger of Mitsui Marine & Fire Insurance Co. (itself descended from the Taishō Marine and Fire Insurance Co. founded in 1918) and The Sumitomo Marine & Fire Insurance. In 2010, April Aioi Insurance Co., Ltd., Nissay Dowa General Insurance Co., Ltd., merged into MSIG, making the group's name changed in to MS&AD Insurance Group Holdings, Inc.. According to this business integration, MS&AD has become the largest property insurance company in Japan, with market share of 33% in 2013. On 8 September 2015, it was announced that Mitsui Sumitomo had agreed to buy the UK insurance firm Amlin for £3.5bn. Group companies Non-life insurance Mitsui Sumitomo Insurance Co., Ltd. Life insurance Mitsui Sumitomo Kirameki Life Insurance Co., Ltd. Mitsui Sumitomo MetLife insurance Co., Ltd. Companies not based in Japan Amlin, plc Cholamandalam MS General Insurance MSIG Insurance Europe AG MSIG Insurance Vietnam Company Limited MS Frontier Reinsurance Ltd. Mitsui Sumitomo Reinsurance Ltd. Mitsui Sumitomo Insurance London Management Ltd. MSI GuaranteedWeather, LLC part, llc Mitsui Sumitomo Insurance – Oceania Financial services Sumitomo Mitsui Asset Management Co., Ltd. MITSUI SUMITOMO INSURANCE Venture Capital Co., Ltd. Risk-related businesses InterRisk Research Institute & Consulting, Inc. MITSUI SUMITOMO INSURANCE Care Network Co., Ltd. American Appraisal Japan Co., Ltd. Annual Reports MSIG Annual Report 2008 MSIG Annual Report 2014 References External links Mitsui Sumitomo Insurance Group Mitsui Sumitomo Insurance – Oceania Companies listed on the Tokyo Stock Exchange Companies listed on the Osaka Exchange Insurance companies based in Tokyo Mitsui Japanese brands Sumitomo Group Japanese companies established in 2001 Financial services companies established in 2001 Holding companies established in 2001 Holding companies based in Tokyo MS&AD Insurance Group