Sumitomo Marine & Fire Insurance Co. and Mitsui Marine & Fire Insurance Co. on Tuesday announced terms under which they will merge next October, creating Japan's largest non-life insurer with assets of 5.7 trillion yen ($51.6 billion). In a joint statement, the companies said 1.09 Mitsui Marine shares will be allocated for one Sumitomo Marine share. The merged entity will be named Mitsui Sumitomo Insurance Co. with Mitsui Marine president Takeo Iguchi and Sumitomo Marine president Hiroyuki Uemura serving as co-chief executive officers. Mitsui Marine, currently Japan's third-largest casualty insurer, and fourth-ranked Sumitomo Marine agreed to merge in March.