Mitsui Sumitomo to invest $4b for 15% stake in W. R. Berkley

MSI expects to finalise the investment within the 2025.

Mitsui Sumitomo Insurance Co., Ltd. (MSI), a subsidiary of MS&AD Insurance Group Holdings, has announced an investment in W. R. Berkley Corporation (WRB). 

Under an Investment and Voting Agreement with WRB’s founding family, MSI will acquire 15% of WRB’s outstanding common stock.

The purchase will be made through open market or private block transactions, with no shares being acquired directly from WRB or its founding family.

The total investment is estimated at approximately $3.8b, based on WRB’s current market capitalisation of $25.1b. 

MSI's designee is expected to be nominated to the WRB Board of Directors by March 2026, contingent on MSI acquiring at least 12.5% of WRB’s outstanding shares and obtaining necessary approvals.

MSI sees this investment as an opportunity to leverage WRB’s position in the US specialty insurance market whilst diversifying its portfolio and increasing capital efficiency.

MSI expects to finalise the investment within the 2025 Japanese fiscal year, ending March 2026. The financial impact of the acquisition will be disclosed from March 2026 onward.