The move comes as its Japanese rival Tokio Marine & Nichido said it is considering selling its 35 percent stake in the Islamic insurer to Hong Leong to end its partnership over strategic differences. Tokio Marine & Nichido is a unit of Tokio Marine Holdings .
Japan's Nikkei newspaper had earlier reported that Tokio Marine was planning to exit its partnership in Hong Leong Tokio Marine due to differences in business strategy. While Tokio Marine wants to sell a broad lineup of life and non-life insurance, Hong Leong is keen to focus on savings-type policies, the paper said.
Mitsui Sumitomo has been looking to expand its overseas operations by forging tie-ups with peers in emerging markets as Japan's non-life insurance market shrinks.
Mitsui Sumitomo Insurance managing executive officer Masaaki Nishikata told Reuters in September that MS&AD Insurance was in talks to buy into several life insurers in Asia as it aims to tap the region's growing economies.
A unit of Tokio Marine halted talks with Malaysia's PacificMas to buy medical insurance provider Pacific Insurance Bhd last July.
The market for Islamic insurance, or takaful, is expected to grow in tandem with rising demand for ethical investments. Total takaful contributions could reach $7.7 billion a year by 2012, Ernst & Young has forecast. But global takaful contributions are less than 1 percent of the total insurance premium spend annually, industry lawyers Clyde & Co have said.