# EDGAR Filing Document

**Accession Number:** 0000011544
**File Stem:** 0001193125-25-335622
**Filing Date:** 2025-12
**Character Count:** 10504
**Document Hash:** cb0ca6be8ee93f507546da635b2b408e
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-335622.hdr.sgml**: 20251229

**ACCESSION NUMBER**: 0001193125-25-335622

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20251223

**FILED AS OF DATE**: 20251229

**DATE AS OF CHANGE**: 20251229

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** MITSUI SUMITOMO INSURANCE CO LTD
- **CENTRAL INDEX KEY:** 0001142206
- **STANDARD INDUSTRIAL CLASSIFICATION:** FIRE, MARINE & CASUALTY INSURANCE [6331]
- **ORGANIZATION NAME:** 02 Finance
- **STATE OF INCORPORATION:** M0
- **FISCAL YEAR END:** 0331

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-15202
- **FILM NUMBER:** 251610743

**BUSINESS ADDRESS:**
- **STREET 1:** 9, KANDA SURUGADAI 3-CHOME
- **STREET 2:** CHIYODA-KU
- **CITY:** TOKYO
- **STATE:** M0
- **ZIP:** 101-8011
- **BUSINESS PHONE:** 81332593111

**MAIL ADDRESS:**
- **STREET 1:** 9, KANDA SURUGADAI 3-CHOME
- **STREET 2:** CHIYODA-KU
- **CITY:** TOKYO
- **STATE:** M0
- **ZIP:** 101-8011
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** MS&AD Insurance Group Holdings, Inc.
- **CENTRAL INDEX KEY:** 0001431048
- **STANDARD INDUSTRIAL CLASSIFICATION:** FIRE, MARINE & CASUALTY INSURANCE [6331]
- **ORGANIZATION NAME:** 02 Finance
- **STATE OF INCORPORATION:** M0
- **FISCAL YEAR END:** 0331

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-15202
- **FILM NUMBER:** 251610742

**BUSINESS ADDRESS:**
- **STREET 1:** 3-7, YAESU 1-CHOME, CHUO-KU
- **CITY:** TOKYO
- **STATE:** M0
- **ZIP:** 103-0028
- **BUSINESS PHONE:** 81-3-6202-5270

**MAIL ADDRESS:**
- **STREET 1:** 3-7, YAESU 1-CHOME, CHUO-KU
- **CITY:** TOKYO
- **STATE:** M0
- **ZIP:** 103-0028

**FORMER NAME:**
- **FORMER CONFORMED NAME:** Mitsui Sumitomo Insurance Group Holdings, Inc.
- **DATE OF NAME CHANGE:** 20080328
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** BERKLEY W R CORP
- **CENTRAL INDEX KEY:** 0000011544
- **STANDARD INDUSTRIAL CLASSIFICATION:** FIRE, MARINE & CASUALTY INSURANCE [6331]
- **ORGANIZATION NAME:** 02 Finance
- **EIN:** 221867895
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 475 STEAMBOAT ROAD
- **STREET 2:** .
- **CITY:** GREENWICH
- **STATE:** CT
- **ZIP:** 06830
- **BUSINESS PHONE:** 2036293000

**MAIL ADDRESS:**
- **STREET 1:** 475 STEAMBOAT ROAD
- **STREET 2:** .
- **CITY:** GREENWICH
- **STATE:** CT
- **ZIP:** 06830

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

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] 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**<sup>*</sup><br>MITSUI SUMITOMO INSURANCE CO LTD<br><sub>(Last) (First) (Middle)</sub><br>9, KANDA-SURUGADAI 3-CHOME, CHIYODA-KU<br><sub>(Street)</sub><br>TOKYO, M0 <br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2025-12-23 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>BERKLEY W R CORP [ WRB ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>MS&AD Insurance Group Holdings, Inc.<br><sub>(Last) (First) (Middle)</sub><br>TOKYO SUMITOMO TWIN BUILDING WEST TOWER,<br>27-2, SHINKAWA 2-CHOME, CHUO-KU,<br><sub>(Street)</sub><br>TOKYO, M0 <br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2025-12-23 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>BERKLEY W R CORP [ WRB ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2025-12-23 |  | P<sup>(1)</sup> |  | 232546 | A | 70.3106<sup>(2)</sup> | 49444484 | D<sup>(3)</sup> |  |
| Common Stock | 2025-12-23 |  | P<sup>(1)</sup> |  | 2027 | A | 71.1535<sup>(4)</sup> | 49446511 | D<sup>(3)</sup> |  |
| Common Stock | 2025-12-24 |  | P<sup>(1)</sup> |  | 220000 | A | 70.5093<sup>(5)</sup> | 49666511 | D<sup>(3)</sup> |  |
| Common Stock | 2025-12-26 |  | P<sup>(1)</sup> |  | 220000 | A | 70.5580<sup>(6)</sup> | 49886511 | D<sup>(3)</sup> |  |
| Common Stock | 2025-12-29 |  | P<sup>(1)</sup> |  | 205000 | A | 70.7726<sup>(7)</sup> | 50091511 | D<sup>(3)</sup> |  |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

---

### Footnotes:

(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 $70.1731 to $70.99. 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 $71.06 to $71.18.

(5) The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.13 to $70.64.

(6) The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.30 to $70.9844.

(7) The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.535 to $70.989.

**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.

**Signature:** MITSUI SUMITOMO INSURANCE CO., LTD., By: /s/ Hironori Morimoto, Name: Hironori Morimoto,  Title: Authorized Signatory  
**Date:** 2025-12-29

**Signature:** MS&AD INSURANCE GROUP HOLDINGS, INC., By: /s/ Hironori Morimoto, Name: Hironori Morimoto, Title: Authorized Signatory  
**Date:** 2025-12-29

### Remarks:

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.**