W.R. Berkley Corporation announced that Mitsui Sumitomo Insurance Co., Ltd. $(MSI)$, a leading Japanese property and casualty insurer, has acquired beneficial ownership of at least 12.5% of the company's outstanding common stock. The shares were acquired pursuant to previously announced agreements with a company owned by members of the Berkley family and related trusts. Under the terms of the agreement, MSI's shares will be voted according to the recommendations of the Berkley family, except in certain cases where they will be voted proportionally to all non-MSI shares. MSI expects to complete its investment under these agreements in the first quarter of 2026. None of the shares were purchased from the Berkley family or W.R. Berkley Corporation itself.