Sompo Japan Nipponkoa Holdings, Inc. (Sompo Japan Nipponkoa Holdings, Inc.) is one of the largest financial insurance companies in Japan, formed by the merger of Sompo Japan and Nipponkoa in 2010 and headquarters in Tokyo. Sompo Japan Nipponkoa Holdings, Inc. is one of the largest financial insurance companies in Japan, formed by the merger of Sompo Japan and Nipponkoa in 2010 and headquarters in Tokyo.