Form 4 Filing for W.R. Berkley Corporation

MS&AD Insurance Group Holdings, Inc. and Mitsui Sumitomo Insurance Co., Ltd. reported a series of stock purchases of W.R. Berkley Corporation (WRB) common stock between December 18 and December 22, 2025. These transactions were executed under a Rule 10b5-1 purchase plan. Mitsui Sumitomo Insurance Co., Ltd. directly acquired shares, while MS&AD Insurance Group Holdings, Inc., as the parent company, may be deemed to beneficially own these shares. The total number of shares acquired across these transactions was 405,940, with weighted average prices ranging from $69.3815 to $70.3257 per share. Following these purchases, the post-transaction share ownership for the reporting entities increased significantly. The filing also includes a disclaimer of beneficial ownership for securities held by WR Berkley & Others LLC (WRBO) and denies the formation of a "group" with WRBO under SEC regulations.