Mitsui Sumitomo buys W. R. Berkley stock under plan

Mitsui Sumitomo Insurance Co., Ltd., a 10% owner of W. R. Berkley Corporation, reported multiple open-market purchases of the issuer’s common stock on January 29–30, 2026 under a Rule 10b5-1 purchase plan adopted on October 3, 2025.

Rhea-AI Filing Summary

Mitsui Sumitomo Insurance Co., Ltd., a 10% owner of W. R. Berkley Corporation, reported multiple open-market purchases of the issuer’s common stock on January 29–30, 2026 under a Rule 10b5-1 purchase plan adopted on October 3, 2025.

On January 29, 2026, Mitsui Sumitomo purchased 262,282 shares at a weighted average price of $68.0816 and 27,718 shares at $68.5605. On January 30, 2026, it purchased 195,000 shares at $68.3611, bringing its directly held position to 56,103,435 common shares. The filing notes that MS&AD Insurance Group Holdings, Inc., Mitsui Sumitomo’s parent, may be deemed to beneficially own these securities but expressly disclaims beneficial ownership except to the extent of its pecuniary interest.

Insider Trade Summary

Net Buyer: 485,000 shares

Net Buy 3 txns

Insider MITSUI SUMITOMO INSURANCE CO LTD, MS&AD Insurance Group Holdings, Inc.

Role 10% Owner | 10% Owner

Bought 485,000 shs ($33.09M)

Type	Security	Shares	Price	Value
Purchase	Common Stock	195,000	$68.3611	$13.33M
Purchase	Common Stock	262,282	$68.0816	$17.86M
Purchase	Common Stock	27,718	$68.5605	$1.90M

Holdings After Transaction: Common Stock — 56,103,435 shares (Direct)

Footnotes (5)

1. F1. The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.
2. F2. The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $67.43 to $68.40. 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 and 5.
3. F3. 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. F4. The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.4004 to $69.015.
5. F5. The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $67.83 to $68.645.

FAQ

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Who bought W. R. Berkley (WRB) shares in this Form 4 filing?

Mitsui Sumitomo Insurance Co., Ltd., a 10% owner of W. R. Berkley, reported the purchases. The shares are held directly by Mitsui Sumitomo, while its parent, MS&AD Insurance Group Holdings, Inc., may be deemed to beneficially own them subject to its pecuniary interest.

How many W. R. Berkley (WRB) shares did Mitsui Sumitomo buy and at what prices?

Mitsui Sumitomo bought 262,282 shares at $68.0816, 27,718 shares at $68.5605, and 195,000 shares at $68.3611. Each reported price is a weighted average for multiple trades executed within stated intraday price ranges.

On what dates were the W. R. Berkley (WRB) share purchases executed?

The reported W. R. Berkley common stock purchases occurred on January 29, 2026 and January 30, 2026. Two transactions were dated January 29 and one transaction was dated January 30, all coded as open-market purchases under transaction code P.

What is the significance of the Rule 10b5-1 plan in this WRB Form 4?

The filing states the purchases were effected under a Rule 10b5-1 purchase plan adopted on October 3, 2025. Such plans pre-schedule trades, providing a structured framework for transactions and are designed to help insiders trade according to predetermined instructions.

How many W. R. Berkley (WRB) shares did Mitsui Sumitomo own after these transactions?

Following the final January 30, 2026 purchase, Mitsui Sumitomo reported 56,103,435 W. R. Berkley common shares beneficially owned. This figure reflects the direct holding after recording all reported open-market purchases in this Form 4 filing.

How does MS&AD Insurance Group relate to the WRB shares reported here?

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

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Accepted by SEC EDGAR 01/30/2026 - 07:30 PM Learn about SEC filing dates

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)
01/29/2026

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	01/29/2026		P(1)		262,282	A	$68.0816(2)	55,880,717	D(3)
Common Stock	01/29/2026		P(1)		27,718	A	$68.5605(4)	55,908,435	D(3)
Common Stock	01/30/2026		P(1)		195,000	A	$68.3611(5)	56,103,435	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 $67.43 to $68.40. 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 and 5.

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 $68.4004 to $69.015.

5. The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $67.83 to $68.645.

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	01/30/2026
	MS&AD INSURANCE GROUP HOLDINGS, INC., By: /s/ Hironori Morimoto, Name: Hironori Morimoto, Title: Authorized Signatory	01/30/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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