Form 4: Mitsui Sumitomo Boosts WR Berkley Stake

Mitsui Sumitomo Insurance Co. Ltd., a 10% owner and director, increased its beneficial ownership in W.R. Berkley Corp. by acquiring 698,000 shares of common stock.

Summary

• Mitsui Sumitomo Insurance Co. Ltd. (MSI), a 10% owner and director of W.R. Berkley Corp. (WRB), acquired a total of 698,000 shares of WRB common stock.
• The purchases were executed pursuant to a Rule 10b5-1 purchase plan adopted on October 3, 2025.
• On January 22, 2026, MSI purchased 330,000 shares at a weighted average price of $67.4505 per share, with prices ranging from $67.09 to $67.66.
• On January 23, 2026, MSI purchased an additional 201,081 shares at a weighted average price of $66.7699 per share, with prices ranging from $66.5195 to $66.9993.
• Also on January 23, 2026, MSI acquired another 166,919 shares at a weighted average price of $67.1803 per share, with prices ranging from $67.00 to $67.9353.
• Following these transactions, MSI directly holds 54,589,504 shares of WRB common stock.
• MS&AD Insurance Group Holdings, Inc. (MS&AD), as the wholly-owned subsidiary of MSI, may be deemed to beneficially own these securities but expressly disclaims beneficial ownership except to the extent of its pecuniary interest.

Sentiment

Score: 8

Explanation: The acquisition of a substantial number of shares by a 10% owner and director, Mitsui Sumitomo Insurance Co. Ltd., indicates strong insider confidence in W.R. Berkley Corp.'s valuation and future performance. This is generally viewed as a very positive signal by the market.

Positives

• A significant 10% owner and director, Mitsui Sumitomo Insurance Co. Ltd., increased its stake in W.R. Berkley Corp. by acquiring 698,000 shares, signaling strong confidence in the company's future.
• The purchases were made under a pre-arranged Rule 10b5-1 plan, indicating a strategic and planned investment decision rather than a reactive one.

Risks

• MS&AD Insurance Group Holdings, Inc. disclaims beneficial ownership of the reported securities, except to the extent of its pecuniary interest, which could imply a nuanced relationship or limited control despite indirect ownership.
• The Reporting Persons disclaim beneficial ownership of securities of the Issuer owned by WR Berkley & Others LLC (WRBO) and disclaim that they and WRBO constitute a 'group' within the meaning of Rule 13d-5(b)(1), which might indicate efforts to avoid certain regulatory implications related to collective ownership.

Future Outlook

No specific forward-looking statements or guidance are provided in this insider transaction report.

Industry Context

This insider transaction reflects a major shareholder's continued investment in W.R. Berkley Corp., an established player in the insurance industry. Such a move by a significant institutional investor like Mitsui Sumitomo Insurance could be interpreted as a positive signal for the company's specific prospects within the broader financial services and insurance sectors.

Related Party Transactions

• Mitsui Sumitomo Insurance Co. Ltd. (MSI), W.R. Berkley Corporation (the 'Issuer'), and WR Berkley & Others LLC ('WRBO') are parties to certain agreements described in, and filed as exhibits to, the Reporting Persons' Schedule 13D filed on December 11, 2025.

Stakeholder Impact

• Shareholders may perceive the significant insider buying by a major institutional investor as a strong vote of confidence in the company's management and future performance, potentially leading to increased investor interest and positive sentiment.
• The transactions reinforce the strategic alignment and commitment of a key 10% owner and director, Mitsui Sumitomo Insurance Co. Ltd., with W.R. Berkley Corp.'s long-term objectives.

Key Dates

Recommendation

The significant acquisition of 698,000 shares by Mitsui Sumitomo Insurance Co. Ltd., a 10% owner and director, indicates strong insider confidence in W.R. Berkley Corp.'s valuation and future performance. This substantial investment, executed under a Rule 10b5-1 plan, suggests a strategic and planned belief in the company's prospects, making it a compelling 'buy' signal for investors.

Keywords

W.R. Berkley Corp., WRB, Mitsui Sumitomo Insurance, MS&AD Insurance Group Holdings, Insider Buying, Form 4, Stock Purchase, 10b5-1 Plan, Insurance, Financial Services, Equity Acquisition