Major W.R. Berkley (NYSE: WRB) holder buys more shares in Rule 10b5-1 plan

Rhea-AI Filing Summary

Mitsui Sumitomo Insurance Co., Ltd., a more than 10% owner of W.R. Berkley Corporation, reported multiple open-market purchases of W.R. Berkley common stock. On January 12, 2026, it bought 256,041 shares at a weighted average price of $68.7344 per share, followed by additional purchases on January 13 and 14, 2026 at weighted average prices between $67.8241 and $69.2333 per share. After these transactions, it directly held 52,726,504 shares of W.R. Berkley common stock. The filing notes that these trades were made under a Rule 10b5-1 purchase plan adopted on October 3, 2025, and that MS&AD Insurance Group Holdings, Inc. may be deemed to beneficially own the securities through its wholly owned subsidiary but disclaims beneficial ownership except for its pecuniary interest.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

MITSUI SUMITOMO INSURANCE CO LTD

(Last) (First) (Middle)

9, KANDA-SURUGADAI 3-CHOME, CHIYODA-KU

(Street)

TOKYO M0

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
BERKLEY W R CORP [ WRB ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
01/12/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	01/12/2026		P(1)		256,041	A	$68.7344(2)	52,171,504	D(3)
Common Stock	01/13/2026		P(1)		118,501	A	$67.8241(4)	52,290,005	D(3)
Common Stock	01/13/2026		P(1)		206,499	A	$68.1479(5)	52,496,504	D(3)
Common Stock	01/14/2026		P(1)		21,728	A	$68.8019(6)	52,518,232	D(3)
Common Stock	01/14/2026		P(1)		208,272	A	$69.2333(7)	52,726,504	D(3)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person^*

MITSUI SUMITOMO INSURANCE CO LTD

(Last) (First) (Middle)

9, KANDA-SURUGADAI 3-CHOME, CHIYODA-KU

(Street)

TOKYO M0

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

MS&AD Insurance Group Holdings, Inc.

(Last) (First) (Middle)

TOKYO SUMITOMO TWIN BUILDING WEST TOWER,

27-2, SHINKAWA 2-CHOME, CHUO-KU,

(Street)

TOKYO M0

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

Explanation of Responses:

1. The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

2. The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.42 to $69.30. The Reporting Persons undertake to provide to W.R. Berkley Corporation (the "Issuer"), any security holder of the Issuer, or the staff of the U.S. Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in this footnote and in footnotes 4, 5, 6 and 7.

3. The shares are held directly by Mitsui Sumitomo Insurance Co., Ltd. ("MSI"). Because MSI is a wholly-owned subsidiary of MS&AD Insurance Group Holdings, Inc. ("MS&AD"), MS&AD may be deemed to beneficially own the reported securities. MS&AD expressly disclaims beneficial ownership of the reported securities, except to the extent of its pecuniary interest therein.

4. The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $67.57 to $67.9993.

5. The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.00 to $68.965.

6. The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.245 to $68.9988.

7. The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $69.00 to $69.74.

Remarks:

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 with the U.S. Securities and Exchange Commission on December 11, 2025. 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.

	MITSUI SUMITOMO INSURANCE CO., LTD., By: /s/ Hironori Morimoto, Name: Hironori Morimoto, Title: Authorized Signatory	01/14/2026
	MS&AD INSURANCE GROUP HOLDINGS, INC., By: /s/ Hironori Morimoto, Name: Hironori Morimoto, Title: Authorized Signatory	01/14/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

Who reported insider transactions in WRB stock?

Mitsui Sumitomo Insurance Co., Ltd. reported the transactions in W.R. Berkley Corporation common stock, with MS&AD Insurance Group Holdings, Inc. listed as an additional reporting person through its ownership of MSI.

What type of WRB insider transactions were reported on this Form 4?

The Form 4 reports open-market purchases (code P) of W.R. Berkley common stock, not sales or option exercises.

How many W.R. Berkley (WRB) shares did the reporting holder own after these trades?

After the reported purchases, Mitsui Sumitomo Insurance Co., Ltd. directly held 52,726,504 shares of W.R. Berkley common stock.

On which dates did the WRB insider purchases occur and at what prices?

The purchases occurred on January 12, 13, and 14, 2026 at weighted average prices of $68.7344, $67.8241 and $68.1479, and $68.8019 and $69.2333 per share, as disclosed in the filing.

Were the WRB insider trades made under a Rule 10b5-1 plan?

Yes. The filing states that the purchases were effected pursuant to a Rule 10b5-1 purchase plan adopted on October 3, 2025.

How does MS&AD Insurance Group relate to the WRB shares on this Form 4?

The shares are held directly by Mitsui Sumitomo Insurance Co., Ltd.. Because MSI is a wholly owned subsidiary of MS&AD Insurance Group Holdings, Inc., MS&AD may be deemed to beneficially own the securities but expressly disclaims beneficial ownership except to the extent of its pecuniary interest.

What price detail is provided for the WRB insider purchases?

The reported prices are weighted average prices. The filing explains that each set of shares was bought in multiple transactions within specified price ranges and offers to provide full trade breakdowns upon request.