[Form 4] BERKLEY W R CORP Insider Trading Activity

Rhea-AI Filing Summary

Mitsui Sumitomo Insurance Co., Ltd., a 10% owner of W. R. Berkley, reported automatic open-market purchases of the company’s common stock under a Rule 10b5-1 trading plan adopted on October 3, 2025. The transactions on February 19-20, 2026 totaled 505,582 shares at weighted average prices around $70–$71 per share. After these trades, Mitsui Sumitomo held 57,668,620 W. R. Berkley shares directly. MS&AD Insurance Group Holdings, Inc., Mitsui Sumitomo’s parent, may be deemed a beneficial owner but expressly disclaims beneficial ownership beyond its economic interest.

Insights

Equity ownership analyst

Large 10% holder increased its W. R. Berkley stake via pre-planned open-market purchases.

Mitsui Sumitomo Insurance Co., Ltd. executed three open-market purchases of W. R. Berkley common stock on February 19-20, 2026, totaling 505,582 shares at weighted average prices between about $70 and $72. These trades occurred under a pre-established Rule 10b5-1 plan adopted on October 3, 2025.

The filing shows total direct holdings rising to 57,668,620 shares after the latest transaction. As a result, a major existing shareholder has modestly increased its position through scheduled purchases, while parent company MS&AD Insurance Group Holdings, Inc. notes it may be deemed a beneficial owner but disclaims beneficial ownership except for its pecuniary interest.

Because these transactions follow a Rule 10b5-1 plan rather than discretionary trading, they typically indicate a structured accumulation strategy rather than short-term sentiment. Future company filings may provide additional context on any broader capital or strategic relationship between W. R. Berkley and these affiliated insurance groups.

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
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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)
02/20/2026

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	02/19/2026		P(1)		300,986	A	$70.5273(2)	57,464,024	D(3)
Common Stock	02/19/2026		P(1)		44,014	A	$71.4951(4)	57,508,038	D(3)
Common Stock	02/20/2026		P(1)		160,582	A	$70.8046(5)	57,668,620	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 $70.0699 to $70.9988. 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 $71.0014 to $72.026.

5. The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.357 to $71.115.

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	02/20/2026
	MS&AD INSURANCE GROUP HOLDINGS, INC., By: /s/ Hironori Morimoto, Name: Hironori Morimoto, Title: Authorized Signatory	02/20/2026
	** Signature of Reporting Person	Date
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FAQ

What did Mitsui Sumitomo Insurance Co., Ltd. buy in W. R. Berkley (WRB)?

Mitsui Sumitomo Insurance Co., Ltd. bought 505,582 shares of W. R. Berkley common stock in open-market transactions. Purchases occurred on February 19-20, 2026 at weighted average prices around $70–$71 per share under a pre-arranged Rule 10b5-1 trading plan.

On what dates did the WRB insider purchases by Mitsui Sumitomo occur?

The reported W. R. Berkley share purchases occurred on February 19 and February 20, 2026. Three open-market transactions were executed under a Rule 10b5-1 plan, with individual weighted average prices reported for each trade in the Form 4 filing’s transaction details and footnotes.

How many WRB shares does Mitsui Sumitomo hold after these transactions?

After the latest open-market purchases, Mitsui Sumitomo Insurance Co., Ltd. directly holds 57,668,620 shares of W. R. Berkley common stock. This updated ownership figure reflects the additional 505,582 shares acquired in the Form 4 transactions on February 19-20, 2026 at weighted average prices near $70–$71.

Were the WRB insider purchases by Mitsui Sumitomo discretionary or pre-planned?

The W. R. Berkley share purchases were made under a pre-planned Rule 10b5-1 trading plan. The footnotes state the plan was adopted on October 3, 2025, indicating trades were scheduled in advance rather than timed at management’s discretion around short-term market movements.

How is MS&AD Insurance Group Holdings, Inc. related to the WRB insider trades?

MS&AD Insurance Group Holdings, Inc. is the parent of Mitsui Sumitomo Insurance Co., Ltd., which directly holds the W. R. Berkley shares. Because Mitsui Sumitomo is wholly owned, MS&AD may be deemed a beneficial owner but expressly disclaims beneficial ownership except for its pecuniary interest.

What price ranges were paid in the recent WRB insider share purchases?

Weighted average prices reported were $70.5273, $71.4951, and $70.8046 per share. Footnotes explain each average reflects multiple trades, with individual transaction prices ranging from $70.0699 to $72.026, and the reporting persons will provide detailed breakdowns upon request.