Mitsui Sumitomo, MS&AD boost W. R. Berkley (NYSE: WRB) position in 13D/A

Rhea-AI Filing Summary

Mitsui Sumitomo Insurance has filed Amendment No. 2 to its Schedule 13D for W. R. Berkley Corporation. Mitsui Sumitomo Insurance Co., Ltd. now beneficially owns 56,458,656 shares of common stock, representing 14.9% of the 380,021,174 shares outstanding as of October 28, 2025.

Between January 15, 2026 and February 6, 2026, Mitsui Sumitomo bought 3,732,152 shares in open-market transactions under a previously disclosed Rule 10b5-1 purchase plan with Jefferies LLC, for a total of $252,827,490.60 paid in cash. Parent company MS&AD Insurance Group Holdings, Inc. may be deemed to indirectly beneficially own these shares through its wholly owned subsidiary but disclaims beneficial ownership.

The filing notes that, under a Framework Agreement and LLC Agreement, the reporting persons may be deemed to share voting power over 67,069,033 additional shares (about 17.6%) held by WR Berkley & Others LLC (Family Holdings), while stating this is not an admission that they form a group with Family Holdings.

Insights

Equity ownership and governance analyst

Mitsui Sumitomo increases its W. R. Berkley stake to 14.9% via planned open‑market purchases.

The amendment shows Mitsui Sumitomo Insurance lifting its beneficial ownership in W. R. Berkley to 56,458,656 shares, or 14.9% of shares outstanding as of October 28, 2025. The purchases, totaling 3,732,152 shares, were executed in the open market under a pre‑established Rule 10b5‑1 plan with Jefferies LLC.

Funding came from cash on hand, and the plan structure suggests an orderly accumulation rather than opportunistic trading, based on the disclosed aggregate purchase price of $252,827,490.60. MS&AD Insurance Group Holdings, Inc. is treated as an indirect beneficial owner under SEC rules because Mitsui Sumitomo is its wholly owned subsidiary, although MS&AD formally disclaims beneficial ownership.

The filing also notes that, through a Framework Agreement and an LLC Agreement, the reporting persons may be deemed to share voting power over 67,069,033 shares (about 17.6%) held by Family Holdings, while explicitly stating this is not an admission they form a Rule 13d-5 group. Future company disclosures may clarify how these aligned stakes influence voting outcomes at shareholder meetings.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 2)

W. R. Berkley Corporation

(Name of Issuer)

Common stock, par value $0.20 per share

(Title of Class of Securities)

084423102

(CUSIP Number)

Mitsui Sumitomo Insurance Co.
Ltd., Attn: Kunihisa Kawasaki, 9, Kanda-Surugadai, 3-chome, Chiyoda-Ku
Tokyo, M0, 101-8011
81-3-3259-1462

Debevoise & Plimpton LLP
Attn: Eric T. Juergens, Esq, 66 Hudson Boulevard
New York, NY, 10001
(212) 909-6000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

02/05/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. 084423102

1

Name of reporting person

Mitsui Sumitomo Insurance Co., Ltd.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

JAPAN

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 56,458,656.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 56,458,656.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

56,458,656.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

14.9 %

14

Type of Reporting Person (See Instructions)

IC

Comment for Type of Reporting Person:

The aggregate amount in row (11) does not reflect shares of common stock, par value $0.20 per share (the "Common Stock"), of W. R. Berkley Corporation (the "Issuer") held by WR Berkley & Others LLC ("Family Holdings"), as further described in Items 5(a) and 6. Percentages are based on 380,021,174 shares of Common Stock outstanding as of October 28, 2025, as reported in the Issuer's Form 10-Q filed with the Securities and Exchange Commission on November 3, 2025.

SCHEDULE 13D

CUSIP No. 084423102

1

Name of reporting person

MS&AD Insurance Group Holdings, Inc.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

JAPAN

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 56,458,656.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 56,458,656.00

11

Aggregate amount beneficially owned by each reporting person

56,458,656.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

14.9 %

14

Type of Reporting Person (See Instructions)

HC

Comment for Type of Reporting Person:

The aggregate amount in row (11) does not reflect shares of Common Stock held by Family Holdings, as further described in Items 5(a) and 6. Percentages are based on 380,021,174 shares of Common Stock outstanding as of October 28, 2025, as reported in the Issuer's Form 10-Q filed with the Securities and Exchange Commission on November 3, 2025.

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common stock, par value $0.20 per share
(b)	Name of Issuer: W. R. Berkley Corporation
(c)	Address of Issuer's Principal Executive Offices: 475 Steamboat Road, Greenwich, CONNECTICUT , 06830.
Item 1 Comment: This Amendment No. 2 amends the Statement on Schedule 13D initially filed on December 11, 2025 with the Securities and Exchange Commission, and amended on January 14, 2026 (as amended, the "Statement") by MS&AD Insurance Group Holdings, Inc., a kabushiki kaisha (stock corporation) organized under the laws of Japan ("MS&AD Holdings"), and Mitsui Sumitomo Insurance Co., Ltd., a kabushiki kaisha (stock corporation) organized under the laws of Japan ("MSI" and together with MS&AD Holdings, the "Reporting Persons").
Item 3.	Source and Amount of Funds or Other Consideration
	Item 3 is hereby amended and supplemented by adding the following paragraph at the end of Item 3: Between January 15, 2026 and February 6, 2026, MSI purchased an aggregate of 3,732,152 shares of Common Stock in the open market at average prices per share as set forth in Schedule I to this Statement for an aggregate purchase price of $252,827,490.60, all of which was paid using cash on hand. The shares of Common Stock were purchased in the open market pursuant to the previously disclosed 10b5-1 purchase plan entered into with Jefferies LLC on October 3, 2025.
Item 5.	Interest in Securities of the Issuer
(a)	Item 5 is hereby amended and restated in its entirety to read as follows: MSI beneficially owns 56,458,656 shares of Common Stock, representing fourteen and nine-tenths percent (14.9%) of the shares of Common Stock outstanding. Because MSI is its wholly-owned subsidiary, MS&AD Holdings may, in accordance with the rules of the Securities and Exchange Commission, be deemed to be an indirect beneficial owner of the shares of Common Stock beneficially owned by MSI. MS&AD Holdings disclaims beneficial ownership of such shares. The percentage beneficial ownership of the Reporting Persons has been determined based on 380,021,174 shares of Common Stock outstanding as of October 28, 2025, as reported in the Issuer's Form 10-Q filed with the Securities and Exchange Commission on November 3, 2025. The beneficial ownership information set forth above does not include any securities of the Issuer beneficially owned by Family Holdings. As a result of the Framework Agreement and LLC Agreement described in Item 6 of this Statement, the Reporting Persons may be deemed to beneficially own and share voting power over the shares of Common Stock beneficially owned by Family Holdings. As of the date hereof, Family Holdings beneficially owns an aggregate of 67,069,033 shares of Common Stock (approximately seventeen and six-tenths percent (17.6%) of the total number of shares of Common Stock outstanding). This Statement is not an admission or acknowledgment that the Reporting Persons constitute a "group" within the meaning of Rule 13d-5(b)(1) under the Act with Family Holdings.
(b)	In addition to the description set forth above in Item 5(a), see the cover pages of this Statement for indications of the respective voting powers and disposition powers of the Reporting Persons.
(c)	Schedule I sets forth the purchases of shares of Common Stock by MSI in the open market between January 15, 2026 and February 6, 2026 and is incorporated herein by reference. Except for the foregoing or as otherwise set forth herein, each of the Reporting Persons reports that neither it, nor to its knowledge, any other person named in Item 2 of this Statement, has effected any transactions in Common Stock during the past 60 days.
(d)	Except as set forth herein, no one other than the Reporting Persons has the right to receive, or the power to direct the receipt of, dividends from, or the proceeds from the sale of, any of the securities of the Issuer beneficially owned by the Reporting Persons as described in this Item 5.
(e)	Not applicable.
Item 7.	Material to be Filed as Exhibits.
	99.8 Schedule I, dated February 6, 2026 99.9 Joint Filing Agreement, dated December 11, 2025, by and between Mitsui Sumitomo Insurance Co., Ltd. and MS&AD Insurance Group Holdings, Inc. (incorporated by reference to Exhibit 99.1 to the Schedule 13D filed by the Reporting Persons with the SEC on December 11, 2025)

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Mitsui Sumitomo Insurance Co., Ltd.

Signature:	/s/ Hironori Morimoto
Name/Title:	Hironori Morimoto/Authorized Signatory
Date:	02/06/2026

MS&AD Insurance Group Holdings, Inc.

Signature:	/s/ Hironori Morimoto
Name/Title:	Hironori Morimoto/Authorized Signatory
Date:	02/06/2026

FAQ

How many W. R. Berkley (WRB) shares does Mitsui Sumitomo now own?

Mitsui Sumitomo Insurance Co., Ltd. now beneficially owns 56,458,656 W. R. Berkley common shares, equal to 14.9% of the 380,021,174 shares outstanding as of October 28, 2025, according to the amended Schedule 13D filing.

What recent share purchases did Mitsui Sumitomo make in W. R. Berkley (WRB)?

Between January 15, 2026 and February 6, 2026, Mitsui Sumitomo purchased 3,732,152 W. R. Berkley shares in open-market trades. The aggregate purchase price was $252,827,490.60, funded entirely with cash on hand under a previously disclosed Rule 10b5-1 plan with Jefferies LLC.

What percentage of W. R. Berkley (WRB) does MS&AD Insurance Group potentially control?

MS&AD’s subsidiary Mitsui Sumitomo owns 14.9% directly, and agreements mean they may be deemed to share voting power over 67,069,033 additional shares (about 17.6%) held by Family Holdings. The filing states this is not an admission they form a regulatory group.

How was the 14.9% ownership figure for W. R. Berkley (WRB) calculated?

The 14.9% ownership is based on 56,458,656 shares beneficially owned by Mitsui Sumitomo divided by 380,021,174 W. R. Berkley common shares outstanding as of October 28, 2025, a figure taken from the company’s Form 10-Q filed November 3, 2025.

Does MS&AD Insurance Group Holdings claim direct ownership of W. R. Berkley (WRB) shares?

MS&AD Insurance Group Holdings may be deemed an indirect beneficial owner of 56,458,656 W. R. Berkley shares owned by Mitsui Sumitomo under SEC rules, because Mitsui Sumitomo is its wholly owned subsidiary. However, MS&AD explicitly disclaims beneficial ownership of these shares in the filing.

What is WR Berkley & Others LLC (Family Holdings) in relation to W. R. Berkley (WRB) stock?

WR Berkley & Others LLC, referred to as Family Holdings, beneficially owns 67,069,033 W. R. Berkley shares, about 17.6% of outstanding stock. Agreements described in the filing mean the reporting persons may be deemed to share voting power over these shares, while disputing that they form a statutory group.