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MS&AD Insurance Group Holdings, Inc.

Disclosed activity across 1 company

Tapewire entity
63840
SEC CIK
0001431048

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Reported relationships

Latest disclosed role at each company.

CompanyLast reported asReport datePublished
BERKLEY W R CORPWRB · Entity 318310% ownerMarch 02, 2026March 04, 2026

Disclosed balances

About these balances

Latest available filing per company, not a reconstructed current portfolio. Matching sequences show the last reported balance with all source rows expandable; grouping alone does not establish account ownership. Do not add unresolved positions together. Filings may omit unchanged positions, and amendments may correct only part of an older disclosure. Jointly reported shares are not necessarily this owner's personal holdings.

BERKLEY W R CORP

Report date March 02, 2026 · Filed March 04, 2026

Jointly reported with Mitsui Sumitomo Insurance Co Ltd

Security / awardOwnership accountDisclosed shares / unitsDisclosure context
Common StockSEC Table I · non-derivativeDirect58,780,450 Last balance in matching sequence After 2026-03-03 transaction · row 4 Source-order balances reconcile. Account continuity and personal attribution are not independently verified.
4 source rows

Row 1 · 2026-03-02 · Purchase · Acquired 45,103 · Balance 58,567,377

F1: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F2: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $71.72 to $72.69. 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 and 6.

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.

Row 2 · 2026-03-02 · Purchase · Acquired 100,897 · Balance 58,668,274

F1: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F4: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $72.71 to $73.415.

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.

Row 3 · 2026-03-03 · Purchase · Acquired 38,991 · Balance 58,707,265

F1: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F5: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $71.1095 to $71.9984.

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.

Row 4 · 2026-03-03 · Purchase · Acquired 73,185 · Balance 58,780,450

F1: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F6: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $72.00 to $72.725.

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.

Filing footnotes · ownership attribution and instrument terms

F1: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F2: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $71.72 to $72.69. 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 and 6.

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.

F4: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $72.71 to $73.415.

F5: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $71.1095 to $71.9984.

F6: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $72.00 to $72.725.

Transaction history

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Purchases/sales include open-market and private transactions. Plan disclosure applies to the filing; individual rows may differ. “Not disclosed” is not “unplanned.”

The cutoff filters transaction history only. Company summaries and owner relationships show the latest available disclosures. Parser corrections can improve historical records.

Transaction dateCompanyActivity / securityShares / unitsReported priceReported valueDetails
January 27, 2026 Filed Jan 29, 2026 01:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 800 $65.86 $52,689.44
Disclosure

SEC source: 0001193125-26-027858 · ownership.xml · nonDerivative · entry 3

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 54,960,304

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F5 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $65.77 to $65.975.

F3 · ownership.direct: 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.

Read SEC document
January 26, 2026 Filed Jan 29, 2026 01:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 76,389 $67.88 $5,185,056.15
Disclosure

SEC source: 0001193125-26-027858 · ownership.xml · nonDerivative · entry 2

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 54,959,504

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F4 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $67.4004 to $68.19.

F3 · ownership.direct: 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.

Read SEC document
January 26, 2026 Filed Jan 29, 2026 01:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 293,611 $66.86 $19,629,480.85
Disclosure

SEC source: 0001193125-26-027858 · ownership.xml · nonDerivative · entry 1

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 54,883,115

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F2 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $66.45 to $67.40. 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, 5, 6, 7, 8, 9, 10 and 11.

F3 · ownership.direct: 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.

Read SEC document
January 23, 2026 Filed Jan 24, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 166,919 $67.18 $11,213,668.50
Disclosure

SEC source: 0001193125-26-021399 · ownership.xml · nonDerivative · entry 3

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 54,589,504

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F5 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $67.00 to $67.9353.

F3 · ownership.direct: 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.

Read SEC document
January 23, 2026 Filed Jan 24, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 201,081 $66.77 $13,426,158.26
Disclosure

SEC source: 0001193125-26-021399 · ownership.xml · nonDerivative · entry 2

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 54,422,585

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F4 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $66.5195 to $66.9993.

F3 · ownership.direct: 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.

Read SEC document
January 22, 2026 Filed Jan 24, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 330,000 $67.45 $22,258,665.00
Disclosure

SEC source: 0001193125-26-021399 · ownership.xml · nonDerivative · entry 1

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 54,221,504

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F2 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $67.09 to $67.66. 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.

F3 · ownership.direct: 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.

Read SEC document
January 21, 2026 Filed Jan 22, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 260,998 $67.60 $17,644,299.99
Disclosure

SEC source: 0001193125-26-018358 · ownership.xml · nonDerivative · entry 4

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 53,891,504

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F6 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $67.41 to $68.13.

F3 · ownership.direct: 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.

Read SEC document
January 21, 2026 Filed Jan 22, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 59,002 $66.95 $3,950,337.31
Disclosure

SEC source: 0001193125-26-018358 · ownership.xml · nonDerivative · entry 3

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 53,630,506

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F5 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $66.5523 to $67.40.

F3 · ownership.direct: 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.

Read SEC document
January 20, 2026 Filed Jan 22, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 44,994 $68.08 $3,063,065.54
Disclosure

SEC source: 0001193125-26-018358 · ownership.xml · nonDerivative · entry 2

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 53,571,504

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F4 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.00 to $68.2013.

F3 · ownership.direct: 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.

Read SEC document
January 20, 2026 Filed Jan 22, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 265,006 $67.75 $17,954,315.50
Disclosure

SEC source: 0001193125-26-018358 · ownership.xml · nonDerivative · entry 1

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 53,526,510

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F2 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $67.00 to $67.9998. 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 and 6.

F3 · ownership.direct: 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.

Read SEC document
January 16, 2026 Filed Jan 17, 2026 00:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 58,691 $68.79 $4,037,101.52
Disclosure

SEC source: 0001193125-26-015569 · ownership.xml · nonDerivative · entry 4

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 53,261,504

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F6 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.6711 to $69.055.

F3 · ownership.direct: 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.

Read SEC document
January 16, 2026 Filed Jan 17, 2026 00:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 241,309 $68.03 $16,416,492.58
Disclosure

SEC source: 0001193125-26-015569 · ownership.xml · nonDerivative · entry 3

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 53,202,813

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F5 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $67.68 to $68.67.

F3 · ownership.direct: 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.

Read SEC document
January 15, 2026 Filed Jan 17, 2026 00:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 68,093 $69.45 $4,728,868.19
Disclosure

SEC source: 0001193125-26-015569 · ownership.xml · nonDerivative · entry 2

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 52,961,504

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F4 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $69.00 to $69.775.

F3 · ownership.direct: 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.

Read SEC document
January 15, 2026 Filed Jan 17, 2026 00:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 166,907 $68.68 $11,462,338.23
Disclosure

SEC source: 0001193125-26-015569 · ownership.xml · nonDerivative · entry 1

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 52,893,411

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F2 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.31 to $68.9978. 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 and 6.

F3 · ownership.direct: 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.

Read SEC document
January 14, 2026 Filed Jan 15, 2026 02:36 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 208,272 $69.23 $14,419,357.86
Disclosure

SEC source: 0001193125-26-013375 · ownership.xml · nonDerivative · entry 5

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 52,726,504

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F7 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $69.00 to $69.74.

F3 · ownership.direct: 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.

Read SEC document
January 14, 2026 Filed Jan 15, 2026 02:36 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 21,728 $68.80 $1,494,927.68
Disclosure

SEC source: 0001193125-26-013375 · ownership.xml · nonDerivative · entry 4

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 52,518,232

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F6 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.245 to $68.9988.

F3 · ownership.direct: 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.

Read SEC document
January 13, 2026 Filed Jan 15, 2026 02:36 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 206,499 $68.15 $14,072,473.20
Disclosure

SEC source: 0001193125-26-013375 · ownership.xml · nonDerivative · entry 3

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 52,496,504

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F5 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.00 to $68.965.

F3 · ownership.direct: 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.

Read SEC document
January 13, 2026 Filed Jan 15, 2026 02:36 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 118,501 $67.82 $8,037,223.67
Disclosure

SEC source: 0001193125-26-013375 · ownership.xml · nonDerivative · entry 2

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 52,290,005

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F4 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $67.57 to $67.9993.

F3 · ownership.direct: 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.

Read SEC document
January 12, 2026 Filed Jan 15, 2026 02:36 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 256,041 $68.73 $17,598,824.51
Disclosure

SEC source: 0001193125-26-013375 · ownership.xml · nonDerivative · entry 1

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 52,171,504

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F2 · price: 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.

F3 · ownership.direct: 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.

Read SEC document
January 09, 2026 Filed Jan 10, 2026 01:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 8,150 $70.12 $571,447.03
Disclosure

SEC source: 0001193125-26-009283 · ownership.xml · nonDerivative · entry 6

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 51,915,463

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F8 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.0011 to $70.4398.

F3 · ownership.direct: 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.

Read SEC document
January 09, 2026 Filed Jan 10, 2026 01:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 105,674 $69.56 $7,351,190.68
Disclosure

SEC source: 0001193125-26-009283 · ownership.xml · nonDerivative · entry 5

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 51,907,313

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F7 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $69.00 to $69.9974.

F3 · ownership.direct: 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.

Read SEC document
January 09, 2026 Filed Jan 10, 2026 01:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 161,176 $68.48 $11,037,590.36
Disclosure

SEC source: 0001193125-26-009283 · ownership.xml · nonDerivative · entry 4

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 51,801,639

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F6 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.36 to $68.9975.

F3 · ownership.direct: 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.

Read SEC document
January 08, 2026 Filed Jan 10, 2026 01:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 151,511 $70.32 $10,653,662.63
Disclosure

SEC source: 0001193125-26-009283 · ownership.xml · nonDerivative · entry 3

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 51,640,463

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F5 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.00 to $70.555.

F3 · ownership.direct: 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.

Read SEC document
January 08, 2026 Filed Jan 10, 2026 01:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 39,302 $69.69 $2,738,964.24
Disclosure

SEC source: 0001193125-26-009283 · ownership.xml · nonDerivative · entry 2

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 51,488,952

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F4 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $69.0527 to $69.995.

F3 · ownership.direct: 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.

Read SEC document
January 08, 2026 Filed Jan 10, 2026 01:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 4,187 $68.79 $288,029.17
Disclosure

SEC source: 0001193125-26-009283 · ownership.xml · nonDerivative · entry 1

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 51,449,650

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F2 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.445 to $68.995. 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, 7 and 8.

F3 · ownership.direct: 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.

Read SEC document
January 07, 2026 Filed Jan 8, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 10,378 $69.20 $718,202.23
Disclosure

SEC source: 0001193125-26-006715 · ownership.xml · nonDerivative · entry 7

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 51,445,463

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F9 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $69.00 to $69.445.

F3 · ownership.direct: 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.

Read SEC document
January 07, 2026 Filed Jan 8, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 254,622 $68.47 $17,433,382.71
Disclosure

SEC source: 0001193125-26-006715 · ownership.xml · nonDerivative · entry 6

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 51,435,085

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F8 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.07 to $68.9999.

F3 · ownership.direct: 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.

Read SEC document
January 06, 2026 Filed Jan 8, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 92,357 $70.21 $6,484,523.51
Disclosure

SEC source: 0001193125-26-006715 · ownership.xml · nonDerivative · entry 5

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 51,180,463

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F7 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.00 to $70.67.

F3 · ownership.direct: 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.

Read SEC document
January 06, 2026 Filed Jan 8, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 122,931 $69.93 $8,596,294.38
Disclosure

SEC source: 0001193125-26-006715 · ownership.xml · nonDerivative · entry 4

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 51,088,106

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F6 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $69.25 to $69.9999.

F3 · ownership.direct: 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.

Read SEC document
January 05, 2026 Filed Jan 8, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 153,686 $70.78 $10,877,510.87
Disclosure

SEC source: 0001193125-26-006715 · ownership.xml · nonDerivative · entry 3

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 50,965,175

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F5 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.60 to $71.0727.

F3 · ownership.direct: 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.

Read SEC document
January 05, 2026 Filed Jan 8, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 35,894 $70.23 $2,520,918.18
Disclosure

SEC source: 0001193125-26-006715 · ownership.xml · nonDerivative · entry 2

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 50,811,489

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F4 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $69.706 to $70.5996.

F3 · ownership.direct: 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.

Read SEC document
January 05, 2026 Filed Jan 8, 2026 00:30 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 11,350 $69.20 $785,415.46
Disclosure

SEC source: 0001193125-26-006715 · ownership.xml · nonDerivative · entry 1

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 50,775,595

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F2 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.7 to $69.6978. 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, 7, 8 and 9.

F3 · ownership.direct: 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.

Read SEC document
January 02, 2026 Filed Jan 3, 2026 00:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 237,734 $69.35 $16,486,306.11
Disclosure

SEC source: 0001193125-26-001178 · ownership.xml · nonDerivative · entry 3

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 50,764,245

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F5 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.92 to $69.77.

F3 · ownership.direct: 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.

Read SEC document
December 31, 2025 Filed Jan 3, 2026 00:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 230,000 $70.27 $16,160,996.00
Disclosure

SEC source: 0001193125-26-001178 · ownership.xml · nonDerivative · entry 2

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 50,526,511

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F4 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.08 to $70.785.

F3 · ownership.direct: 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.

Read SEC document
December 30, 2025 Filed Jan 3, 2026 00:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 205,000 $70.83 $14,519,822.00
Disclosure

SEC source: 0001193125-26-001178 · ownership.xml · nonDerivative · entry 1

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 50,296,511

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F2 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.6 to $71.145. 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.

F3 · ownership.direct: 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.

Read SEC document
December 29, 2025 Filed Dec 30, 2025 00:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 205,000 $70.77 $14,508,383.00
Disclosure

SEC source: 0001193125-25-335622 · ownership.xml · nonDerivative · entry 5

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 50,091,511

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F7 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.535 to $70.989.

F3 · ownership.direct: 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.

Read SEC document
December 26, 2025 Filed Dec 30, 2025 00:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 220,000 $70.56 $15,522,760.00
Disclosure

SEC source: 0001193125-25-335622 · ownership.xml · nonDerivative · entry 4

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 49,886,511

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F6 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.30 to $70.9844.

F3 · ownership.direct: 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.

Read SEC document
December 24, 2025 Filed Dec 30, 2025 00:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 220,000 $70.51 $15,512,046.00
Disclosure

SEC source: 0001193125-25-335622 · ownership.xml · nonDerivative · entry 3

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 49,666,511

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F5 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.13 to $70.64.

F3 · ownership.direct: 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.

Read SEC document
December 23, 2025 Filed Dec 30, 2025 00:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 2,027 $71.15 $144,228.14
Disclosure

SEC source: 0001193125-25-335622 · ownership.xml · nonDerivative · entry 2

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 49,446,511

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F4 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $71.06 to $71.18.

F3 · ownership.direct: 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.

Read SEC document
December 23, 2025 Filed Dec 30, 2025 00:00 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 232,546 $70.31 $16,350,448.79
Disclosure

SEC source: 0001193125-25-335622 · ownership.xml · nonDerivative · entry 1

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 49,444,484

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F2 · price: 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.

F3 · ownership.direct: 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.

Read SEC document
December 22, 2025 Filed Dec 23, 2025 01:45 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 162,060 $70.33 $11,396,982.94
Disclosure

SEC source: 0001193125-25-329220 · ownership.xml · nonDerivative · entry 4

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 49,211,938

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F6 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $70.20 to $70.64.

F3 · ownership.direct: 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.

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December 22, 2025 Filed Dec 23, 2025 01:45 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 39,940 $69.97 $2,794,665.70
Disclosure

SEC source: 0001193125-25-329220 · ownership.xml · nonDerivative · entry 3

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 49,049,878

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F5 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $69.23 to $70.1973.

F3 · ownership.direct: 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.

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December 19, 2025 Filed Dec 23, 2025 01:45 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 204,000 $69.50 $14,178,612.00
Disclosure

SEC source: 0001193125-25-329220 · ownership.xml · nonDerivative · entry 2

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 49,009,938

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F4 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $69.36 to $69.955.

F3 · ownership.direct: 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.

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December 18, 2025 Filed Dec 23, 2025 01:45 UTC BERKLEY W R CORP WRB · Entity 3183 PurchaseCommon Stock 204,350 $69.38 $14,178,109.53
Disclosure

SEC source: 0001193125-25-329220 · ownership.xml · nonDerivative · entry 1

MITSUI SUMITOMO INSURANCE CO LTD · CIK 0001142206 · 10% owner

MS&AD Insurance Group Holdings, Inc. · CIK 0001431048 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 48,805,938

F1 · kind: The purchases reported on this Form 4 were effected pursuant to a Rule 10b5-1 purchase plan, adopted October 3, 2025.

F2 · price: The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $68.82 to $69.60. 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 and 6.

F3 · ownership.direct: 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.

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Value uses the disclosed total when available, otherwise shares × reported transaction price. It is not an estimate of exercise cash cost or investment performance.