WRB

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

SEC source: 0001236251-25-000006 · form4.xml · nonDerivative · entry 1

SHIEL JAMES G · CIK 0001236251 · EVP - Investments

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 797,197

F1 · shares: On December 18, 2025, the reporting person donated 1,250 directly owned shares of common stock to a donor-advisor fund, which will use the gifted shares for charitable purposes.

F2 · balance_after: Includes 647,032 shares of common stock underlying restricted stock units ("RSUs"), all of which have vested (the receipt of which has been deferred) and does not include unvested shares of common stock underlying performance-based RSUs.

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.

SEC source: 0001062993-25-014721 · form4.xml · nonDerivative · entry 2

SHIEL JAMES G · CIK 0001236251 · EVP - Investments

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 798,447

F2 · shares: Represents payment of tax liability by withholding securities incident to the vesting of RSUs.

F3 · balance_after: Includes 647,032 shares of common stock underlying RSUs, all of which have vested (the receipt of which has been deferred) and does not include unvested shares of common stock underlying performance-based RSUs.

SEC source: 0001062993-25-014721 · form4.xml · nonDerivative · entry 1

SHIEL JAMES G · CIK 0001236251 · EVP - Investments

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 799,191

F1 · shares: Represents the vesting of tranches of performance-based restricted stock units ("RSUs") granted in 2020, 2021 and 2022 under the W. R. Berkley Corporation 2018 Stock Incentive Plan for the three-year performance period ending June 30, 2025 (consisting of 6,396 shares; 5,549 shares; and 4,181 shares, respectively).

SEC source: 0001062993-25-014720 · form4.xml · nonDerivative · entry 2

Sgaglione Lucille T · CIK 0001491845 · EVP

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 241,036

F2 · shares: Represents payment of tax liability by withholding securities incident to the vesting of RSUs.

F3 · balance_after: Represents shares of common stock underlying RSUs, all of which have vested (the receipt of which has been deferred) and does not include unvested shares of common stock underlying performance-based RSUs.

SEC source: 0001062993-25-014720 · form4.xml · nonDerivative · entry 1

Sgaglione Lucille T · CIK 0001491845 · EVP

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 241,753

F1 · shares: Represents the vesting of tranches of performance-based restricted stock units ("RSUs") granted in 2020, 2021 and 2022 under the W. R. Berkley Corporation 2018 Stock Incentive Plan for the three-year performance period ending June 30, 2025 (consisting of 6,396 shares; 5,549 shares; and 4,181 shares, respectively).

SEC source: 0001062993-25-014719 · form4.xml · nonDerivative · entry 2

Welt Philip S · CIK 0001764818 · EVP & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 200,539

F2 · shares: Represents payment of tax liability by withholding securities incident to the vesting of RSUs.

F3 · balance_after: Includes 126,256 shares of common stock underlying RSUs, all of which have vested (the receipt of which has been deferred) and does not include unvested shares of common stock underlying performance-based RSUs.

SEC source: 0001062993-25-014719 · form4.xml · nonDerivative · entry 1

Welt Philip S · CIK 0001764818 · EVP & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 201,217

F1 · shares: Represents the vesting of tranches of performance-based restricted stock units ("RSUs") granted in 2020, 2021 and 2022 under the W. R. Berkley Corporation 2018 Stock Incentive Plan for the three-year performance period ending June 30, 2025 (consisting of 6,396 shares; 5,549 shares; and 4,181 shares, respectively).

SEC source: 0001062993-25-014716 · form4.xml · nonDerivative · entry 2

BERKLEY WILLIAM R · CIK 0000918186 · Director · Executive Chairman · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,363,285

F2 · shares: Represents payment of tax liability by withholding securities incident to the vesting of RSUs.

F3 · balance_after: Includes 7,618,901 shares of common stock underlying RSUs, all of which have vested (the receipt of which has been deferred) and does not include unvested shares of common stock underlying performance-based RSUs.

SEC source: 0001062993-25-014716 · form4.xml · nonDerivative · entry 1

BERKLEY WILLIAM R · CIK 0000918186 · Director · Executive Chairman · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,367,562

F1 · shares: Represents the vesting of tranches of performance-based restricted stock units ("RSUs") granted in 2020, 2021 and 2022 under the W. R. Berkley Corporation 2018 Stock Incentive Plan for the three-year performance period ending June 30, 2025 (consisting of 43,765 shares; 38,840 shares; and 29,264 shares, respectively).

SEC source: 0001062993-25-014717 · form4.xml · nonDerivative · entry 2

BERKLEY WILLIAM R JR · CIK 0001236253 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,552,770

F2 · shares: Represents payment of tax liability by withholding securities incident to the vesting of RSUs.

F3 · balance_after: Includes 3,181,240 shares of common stock underlying RSUs, all of which have vested (the receipt of which has been deferred) and does not include unvested shares of common stock underlying performance-based RSUs.

SEC source: 0001062993-25-014717 · form4.xml · nonDerivative · entry 1

BERKLEY WILLIAM R JR · CIK 0001236253 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,557,466

F1 · shares: Represents the vesting of tranches of performance-based restricted stock units ("RSUs") granted in 2020, 2021 and 2022 under the W. R. Berkley Corporation 2018 Stock Incentive Plan for the three-year performance period ending June 30, 2025 (consisting of 43,765 shares; 38,840 shares; and 29,264 shares, respectively).

SEC source: 0001062993-25-014718 · form4.xml · nonDerivative · entry 2

Baio Richard Mark · CIK 0001463038 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 214,175

F2 · shares: Represents payment of tax liability by withholding securities incident to the vesting of RSUs.

F3 · balance_after: Includes 211,550 shares of common stock underlying RSUs, all of which have vested (the receipt of which has been deferred) and does not include unvested shares of common stock underlying performance-based RSUs.

SEC source: 0001062993-25-014718 · form4.xml · nonDerivative · entry 1

Baio Richard Mark · CIK 0001463038 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 214,919

F1 · shares: Represents the vesting of tranches of performance-based restricted stock units ("RSUs") granted in 2020, 2021 and 2022 under the W. R. Berkley Corporation 2018 Stock Incentive Plan for the three-year performance period ending June 30, 2025 (consisting of 6,396 shares; 5,549 shares; and 4,181 shares, respectively).

SEC source: 0001062993-25-011687 · form4.xml · nonDerivative · entry 1

BERKLEY WILLIAM R · CIK 0000918186 · Director · Executive Chairman · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,255,693

F1 · shares: Represents award granted pursuant to the terms of the W. R. Berkley Corporation 2009 Directors Stock Plan, as amended and restated.

F2 · balance_after: Includes 7,511,309 shares of common stock underlying vested Restricted Stock Units ("RSUs") (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-25-011686 · form4.xml · nonDerivative · entry 1

Mosley Daniel Lynn · CIK 0001961594 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 11,795

F1 · shares: Represents award granted pursuant to the terms of the W. R. Berkley Corporation 2009 Directors Stock Plan, as amended and restated.

F2 · balance_after: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F3 · balance_after: Includes an increase of 3,006 shares of common stock beneficially owned by the reporting person resulting from the Stock Split.

SEC source: 0001062993-25-011684 · form4.xml · nonDerivative · entry 1

Mattson Marie Angela · CIK 0002026387 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 6,577

F1 · shares: Represents award granted pursuant to the terms of the W. R. Berkley Corporation 2009 Directors Stock Plan, as amended and restated.

F2 · balance_after: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F3 · balance_after: Includes an increase of 1,267 shares of common stock beneficially owned by the reporting person resulting from the Stock Split.

SEC source: 0001062993-25-011682 · form4.xml · nonDerivative · entry 1

Ferre Maria Luisa · CIK 0001289698 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 56,144

F1 · shares: Represents award granted pursuant to the terms of the W. R. Berkley Corporation 2009 Directors Stock Plan, as amended and restated.

F2 · balance_after: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F3 · balance_after: Includes an increase of 17,789 shares of common stock beneficially owned by the reporting person resulting from the Stock Split.

SEC source: 0001062993-25-011681 · form4.xml · nonDerivative · entry 1

Talisman Jonathan · CIK 0001794251 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,090

F1 · shares: Represents award granted pursuant to the terms of the W. R. Berkley Corporation 2009 Directors Stock Plan, as amended and restated.

F2 · balance_after: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F3 · balance_after: Includes an increase of 9,104 shares of common stock beneficially owned by the reporting person resulting from the Stock Split.

SEC source: 0001062993-25-011680 · form4.xml · nonDerivative · entry 1

Farrell Mary C · CIK 0001355414 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 16,288

F1 · shares: Represents award granted pursuant to the terms of the W. R. Berkley Corporation 2009 Directors Stock Plan, as amended and restated.

F2 · balance_after: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F3 · balance_after: Includes an increase of 4,504 shares of common stock beneficially owned by the reporting person resulting from the Stock Split.

SEC source: 0001062993-25-011678 · form4.xml · nonDerivative · entry 1

BLAYLOCK RONALD E · CIK 0001214686 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 118,900

F1 · shares: Represents award granted pursuant to the terms of the W. R. Berkley Corporation 2009 Directors Stock Plan, as amended and restated.

F2 · balance_after: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F3 · balance_after: Includes an increase of 38,708 shares of common stock beneficially owned by the reporting person resulting from the Stock Split.

SEC source: 0001062993-25-011679 · form4.xml · nonDerivative · entry 1

BERKLEY WILLIAM R JR · CIK 0001236253 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,445,597

F1 · shares: Represents award granted pursuant to the terms of the W. R. Berkley Corporation 2009 Directors Stock Plan, as amended and restated.

F2 · balance_after: Includes 3,074,067 shares of common stock underlying vested Restricted Stock Units ("RSUs") (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-25-011677 · form4.xml · nonDerivative · entry 1

Augostini Christopher L · CIK 0001550828 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 106,769

F1 · shares: Represents award granted pursuant to the terms of the W. R. Berkley Corporation 2009 Directors Stock Plan, as amended and restated.

F2 · balance_after: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F3 · balance_after: Includes an increase of 34,664 shares of common stock beneficially owned by the reporting person resulting from the Stock Split.

SEC source: 0001062993-25-011676 · form4.xml · nonDerivative · entry 1

Rusbuldt Robert Alan · CIK 0002071104 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,776

F1 · shares: Represents award granted pursuant to the terms of the W. R. Berkley Corporation 2009 Directors Stock Plan, as amended and restated.

SEC source: 0001062993-25-000666 · form4.xml · nonDerivative · entry 1

SHIEL JAMES G · CIK 0001236251 · EVP - Investments

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 783,065

F1 · shares: On January 8, 2025, the reporting person gifted 208,000 directly owned shares of common stock to his spouse, who subsequently gifted them to the 2022 SLAT, of which the reporting person is a co-trustee and beneficiary.

F2 · balance_after: Includes 631,650 shares of common stock underlying vested restricted stock units ("RSUs") (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-021226 · form4.xml · nonDerivative · entry 1

SHIEL JAMES G · CIK 0001236251 · EVP - Investments

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 991,065

F1 · shares: On December 26, 2024, the reporting person donated 1,500 directly owned shares of common stock to a donor-advisor fund, which will use the gifted shares for charitable purposes.

F2 · balance_after: Includes 631,650 shares of common stock underlying vested restricted stock units ("RSUs") (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-015399 · form4.xml · nonDerivative · entry 2

SHIEL JAMES G · CIK 0001236251 · EVP - Investments

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 992,565

F4 · shares: Represents payment of tax liability by withholding securities incident to the vesting of RSUs.

F5 · balance_after: Includes 631,650 shares of common stock underlying vested RSUs (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-015399 · form4.xml · nonDerivative · entry 1

SHIEL JAMES G · CIK 0001236251 · EVP - Investments

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 993,371

F1 · shares: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F2 · shares: Represents the vesting of tranches of shares of common stock underlying performance-based restricted stock units ("RSUs") granted in 2019, 2020 and 2021 under the W. R. Berkley Corporation 2018 Stock Incentive Plan for the three-year performance period ending June 30, 2024 (consisting of 5,529 shares; 6,397 shares; and 5,547 shares, respectively).

F3 · balance_after: Includes an increase of 325,300 shares of common stock beneficially owned by the reporting person resulting from the Stock Split, including 204,995 shares of common stock underlying vested RSUs (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-015398 · form4.xml · nonDerivative · entry 2

Sgaglione Lucille T · CIK 0001491845 · EVP

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 225,627

F4 · shares: Represents payment of tax liability by withholding securities incident to the vesting of RSUs.

F5 · balance_after: Represents shares of common stock underlying vested RSUs (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-015398 · form4.xml · nonDerivative · entry 1

Sgaglione Lucille T · CIK 0001491845 · EVP

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 226,403

F1 · shares: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F2 · shares: Represents the vesting of tranches of shares of common stock underlying performance-based restricted stock units ("RSUs") granted in 2019, 2020 and 2021 under the W. R. Berkley Corporation 2018 Stock Incentive Plan for the three-year performance period ending June 30, 2024 (consisting of 5,529 shares; 6,397 shares; and 5,547 shares, respectively).

F3 · balance_after: Includes an increase of 69,644 shares of common stock underlying vested RSUs (the receipt of which has been deferred) beneficially owned by the reporting person resulting from the Stock Split, and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-015396 · form4.xml · nonDerivative · entry 2

Welt Philip S · CIK 0001764818 · EVP & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 185,091

F4 · shares: Represents payment of tax liability by withholding securities incident to the vesting of RSUs.

F5 · balance_after: Includes 110,808 shares of common stock underlying vested RSUs (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-015396 · form4.xml · nonDerivative · entry 1

Welt Philip S · CIK 0001764818 · EVP & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 185,826

F1 · shares: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F2 · shares: Represents the vesting of tranches of shares of common stock underlying performance-based restricted stock units ("RSUs") granted in 2019, 2020 and 2021 under the W. R. Berkley Corporation 2018 Stock Incentive Plan for the three-year performance period ending June 30, 2024 (consisting of 5,529 shares; 6,397 shares; and 5,547 shares, respectively).

F3 · balance_after: Includes an increase of 56,118 shares of common stock beneficially owned by the reporting person resulting from the Stock Split, including 31,357 shares of common stock underlying vested RSUs (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-015397 · form4.xml · nonDerivative · entry 2

Baio Richard Mark · CIK 0001463038 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 198,793

F4 · shares: Represents payment of tax liability by withholding securities incident to the vesting of RSUs.

F5 · balance_after: Includes 196,168 shares of common stock underlying vested RSUs (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-015397 · form4.xml · nonDerivative · entry 1

Baio Richard Mark · CIK 0001463038 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 199,599

F1 · shares: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F2 · shares: Represents the vesting of tranches of shares of common stock underlying performance-based restricted stock units ("RSUs") granted in 2019, 2020 and 2021 under the W. R. Berkley Corporation 2018 Stock Incentive Plan for the three-year performance period ending June 30, 2024 (consisting of 5,529 shares; 6,397 shares; and 5,547 shares, respectively).

F3 · balance_after: Includes an increase of 60,710 shares of common stock beneficially owned by the reporting person resulting from the Stock Split, including 59,835 shares of common stock underlying vested RSUs (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-015395 · form4.xml · nonDerivative · entry 2

BERKLEY WILLIAM R JR · CIK 0001236253 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,442,821

F4 · shares: Represents payment of tax liability by withholding securities incident to the vesting of RSUs.

F5 · balance_after: Includes 3,074,067 shares of common stock underlying vested RSUs (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-015395 · form4.xml · nonDerivative · entry 1

BERKLEY WILLIAM R JR · CIK 0001236253 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,447,876

F1 · shares: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F2 · shares: Represents the vesting of tranches of shares of common stock underlying performance-based restricted stock units ("RSUs") granted in 2019, 2020 and 2021 under the W. R. Berkley Corporation 2018 Stock Incentive Plan for the three-year performance period ending June 30, 2024 (consisting of 37,826 shares; 43,766 shares; and 38,838 shares, respectively).

F3 · balance_after: Includes an increase of 1,442,482 shares of common stock beneficially owned by the reporting person resulting from the Stock Split, including 986,231 shares of common stock underlying vested RSUs (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-015394 · form4.xml · nonDerivative · entry 2

BERKLEY WILLIAM R · CIK 0000918186 · Director · Executive Chairman · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,252,917

F4 · shares: Represents payment of tax liability by withholding securities incident to the vesting of RSUs.

F5 · balance_after: Includes 7,511,309 shares of common stock underlying vested RSUs (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-015394 · form4.xml · nonDerivative · entry 1

BERKLEY WILLIAM R · CIK 0000918186 · Director · Executive Chairman · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,257,521

F1 · shares: On July 10, 2024, the Company's common stock split on a 3-for-2 basis (the "Stock Split"). The number of securities acquired, disposed of, or beneficially owned reported on this Form reflect such Stock Split.

F2 · shares: Represents the vesting of tranches of shares of common stock underlying performance-based restricted stock units ("RSUs") granted in 2019, 2020 and 2021 under the W. R. Berkley Corporation 2018 Stock Incentive Plan for the three-year performance period ending June 30, 2024 (consisting of 37,826 shares; 43,766 shares; and 38,838 shares, respectively).

F3 · balance_after: Includes an increase of 5,712,363 shares of common stock beneficially owned by the reporting person resulting from the Stock Split, including 2,465,161 shares of common stock underlying vested RSUs (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.

SEC source: 0001062993-24-012478 · form4.xml · nonDerivative · entry 1

BERKLEY WILLIAM R · CIK 0000918186 · Director · Executive Chairman · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 11,424,727

F1 · shares: Represents award granted pursuant to the terms of the W. R. Berkley Corporation 2009 Directors Stock Plan, as amended and restated.

F2 · balance_after: Includes 4,930,321 shares of common stock underlying vested Restricted Stock Units ("RSUs") (the receipt of which has been deferred) and does not include shares of common stock underlying unvested performance-based RSUs.