On 31 March 2003, PT Asuransi Sumitomo Marine and Pool transferred its business portfolio including its employees to PT Asuransi Mitsui Marine Indonesia.

On 1 April 2003, the company's name was changed from PT Asuransi Mitsui Marine Indonesia to PT Asuransi Mitsui Sumitomo Indonesia, following the parent company's new name of Mitsui Sumitomo Insurance Co., Ltd., Japan and also by the transfer of business portfolio of PT Asuransi Sumitomo Marine and Pool to PT Asuransi Mitsui Marine Indonesia.

As of 22 November 2002, composition of shares was changed to become 100% owned by Mitsui Sumitomo Insurance Co., Ltd., Japan.

On 1 October 2001, the name of the parent company in Japan was changed to Mitsui Sumitomo Insurance Co., Ltd as a result of a merger between Mitsui Marine and Fire Insurance Co., Ltd and Sumitomo Marine and Fire Insurance Co., Ltd.

Since then, the majority shareholder became Mitsui Sumitomo Insurance Co., Ltd. with the composition remaining the same.

As of 21 December 2001, shareholding composition of PT Asuransi Mitsui Marine Indonesia became 80% held by the Japanese party and 20% held by the Indonesian party.

Subsequently, on 16 December 1999, the paid-up capital was increased to IDR 40 billion with no change in the share composition.

On 1 April 1996, the company's name was changed from PT Asuransi Insindo Taisho to PT Asuransi Mitsui Marine Indonesia, following the change of parent company's name from Taisho Marine and Fire Insurance Co., Ltd. to become Mitsui Marine and Fire Insurance Co., Ltd.

Since December 1990, as the paid-up capital was increased to IDR 15 billion, the share composition became 79.60% held by the Japanese party, with the remaining 20.40% by the Indonesian party.

Due to the changes in government regulations, in 1983 the composition of shares of the Company was altered to become 51% held by the Indonesian party and 49% by the Japanese party.

On 22 October 1975, PT Asuransi Insido Taisho with business license in general insurance industry No. Kep-588/MD/1987 on 2 February1987 was officially established as a joint venture company between Taisho Marine and Fire Insurance Co., Ltd., Japan (70% shares) and PT Maskapai Asuransi Indonesia (30% shares), with a statutory capital of IDR 750 million.