Form 4: 10% Owner Boosts WRB Stake via 10b5-1 Plan

Mitsui Sumitomo Insurance Co. Ltd. and MS&AD Insurance Group Holdings, Inc. acquired 40,000 shares of W.R. Berkley Corp. common stock through a Rule 10b5-1 plan.

Summary

• Mitsui Sumitomo Insurance Co. Ltd. (MSI) and MS&AD Insurance Group Holdings, Inc. (MS&AD), both 10% owners of W.R. Berkley Corp. (WRB), reported the acquisition of common stock.
• The purchases were executed pursuant to a Rule 10b5-1 purchase plan, which was adopted on October 3, 2025.
• On February 5, 2026, MSI acquired 6,528 shares at a weighted average price of $70.7889 per share (ranging from $70.4471 to $70.9964) and an additional 13,472 shares at a weighted average price of $71.2528 per share (ranging from $71.0009 to $71.60).
• On February 6, 2026, MSI acquired 15,694 shares at a weighted average price of $70.4608 per share (ranging from $70.1381 to $70.9994) and an additional 4,306 shares at a weighted average price of $71.3915 per share (ranging from $71.0012 to $71.8345).
• In total, 40,000 shares of common stock were acquired across these four transactions.
• Following these transactions, the total beneficial ownership of common stock by MSI is 56,458,656 shares.
• MS&AD, as the wholly-owned subsidiary of MSI, may be deemed to beneficially own the reported securities but expressly disclaims beneficial ownership except to the extent of its pecuniary interest.

Sentiment

Score: 7

Explanation: StockSavvy.ai views this as a moderately positive signal, as a significant institutional investor is increasing its stake, suggesting confidence in the company's valuation and future performance, particularly given the execution through a pre-planned 10b5-1 program.

Positives

• A significant 10% owner, Mitsui Sumitomo Insurance Co. Ltd., increased its stake in W.R. Berkley Corp. by acquiring 40,000 shares, signaling confidence in the company's future prospects.
• The purchases were made under a Rule 10b5-1 plan, indicating a pre-planned investment strategy rather than opportunistic trading based on immediate non-public information.

Risks

• 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' under Rule 13d-5(b)(1), which could imply potential regulatory scrutiny or differing interpretations of control or influence.

Future Outlook

No specific forward-looking statements or guidance are provided in this filing beyond the execution of a pre-planned stock purchase program.

Management Comments

• MS&AD expressly disclaims beneficial ownership of the reported securities, except to the extent of its pecuniary interest therein, as MSI is a wholly-owned subsidiary.
• The Reporting Persons disclaim beneficial ownership of the securities of the Issuer owned by WRBO and disclaim that the Reporting Persons and WRBO constitute a 'group' within the meaning of Rule 13d-5(b)(1) under the Securities Exchange Act of 1934, as amended.

Industry Context

StockSavvy.ai notes that significant purchases by a major institutional shareholder like Mitsui Sumitomo Insurance, a global insurance giant, can signal confidence in the issuer's long-term prospects within the insurance sector, especially when executed through a pre-planned 10b5-1 program. This activity suggests a strategic investment decision by a sophisticated player in the financial services industry.

Corporate Governance

Related Party Transactions

• MSI, the Issuer, and WR Berkley & Others LLC (WRBO) are party to certain agreements described in, and filed as exhibits to, the Reporting Persons' Schedule 13D filed on December 11, 2025. This indicates a pre-existing relationship that could involve related party dealings, though no new transactions beyond the stock purchases are detailed here.

Stakeholder Impact

• Shareholders: May view the increased stake by a major institutional investor as a positive indicator of confidence in the company's value and future prospects.
• Regulatory Authorities: The use of a 10b5-1 plan and the disclaimers regarding beneficial ownership and group formation demonstrate adherence to SEC regulations and transparency in reporting.

Key Dates

Recommendation

The acquisition of 40,000 shares by a significant 10% owner, Mitsui Sumitomo Insurance, through a pre-planned 10b5-1 program, signals strong conviction in W.R. Berkley Corp.'s valuation and future performance. This insider buying activity suggests that a well-informed institutional investor sees upside potential, making it a favorable indicator for other investors.

Keywords

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