If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).






SCHEDULE 13D




Comment for Type of Reporting Person:
The aggregate amount in row (11) does not reflect shares of common stock, par value $0.20 per share (the "Common Stock"), of W. R. Berkley Corporation (the "Issuer") held by MS&AD Insurance Group Holdings, Inc., a kabushiki kaisha (stock corporation) organized under the laws of Japan ("MS&AD Holdings"), and Mitsui Sumitomo Insurance Co., Ltd., a kabushiki kaisha (stock corporation) organized under the laws of Japan ("MSI" and together with MS&AD Holdings, the "MSI Entities"), as further described in Items 5(a) and 6. Percentages are based on 374,490,856 shares of Common Stock outstanding as of February 23, 2026, as reported in the Issuer's Form 10-K filed with the Securities and Exchange Commission on February 27, 2026.


SCHEDULE 13D




Comment for Type of Reporting Person:
The aggregate amount in row (11) does not reflect shares of Common Stock held by the MSI Entities, as further described in Items 5(a) and 6. Percentages are based on 374,490,856 shares of Common Stock outstanding as of February 23, 2026, as reported in the Issuer's Form 10-K filed with the Securities and Exchange Commission on February 27, 2026.


SCHEDULE 13D




Comment for Type of Reporting Person:
The aggregate amount in row (11) does not reflect shares of Common Stock held by the MSI Entities, as further described in Items 5(a) and 6. Percentages are based on 374,490,856 shares of Common Stock outstanding as of February 23, 2026, as reported in the Issuer's Form 10-K filed with the Securities and Exchange Commission on February 27, 2026.


SCHEDULE 13D




Comment for Type of Reporting Person:
The aggregate amount in row (11) does not reflect shares of Common Stock held by the MSI Entities, as further described in Items 5(a) and 6. Percentages are based on 374,490,856 shares of Common Stock outstanding as of February 23, 2026, as reported in the Issuer's Form 10-K filed with the Securities and Exchange Commission on February 27, 2026.


SCHEDULE 13D




Comment for Type of Reporting Person:
The aggregate amount in row (11) does not reflect shares of Common Stock held by the MSI Entities, as further described in Items 5(a) and 6. Percentages are based on 374,490,856 shares of Common Stock outstanding as of February 23, 2026, as reported in the Issuer's Form 10-K filed with the Securities and Exchange Commission on February 27, 2026.


SCHEDULE 13D




Comment for Type of Reporting Person:
The aggregate amount in row (11) does not reflect shares of Common Stock held by the MSI Entities, as further described in Items 5(a) and 6. Percentages are based on 374,490,856 shares of Common Stock outstanding as of February 23, 2026, as reported in the Issuer's Form 10-K filed with the Securities and Exchange Commission on February 27, 2026.


SCHEDULE 13D




Comment for Type of Reporting Person:
The aggregate amount in row (11) does not reflect shares of Common Stock held by the MSI Entities, as further described in Items 5(a) and 6. Percentages are based on 374,490,856 shares of Common Stock outstanding as of February 23, 2026, as reported in the Issuer's Form 10-K filed with the Securities and Exchange Commission on February 27, 2026.


SCHEDULE 13D




Comment for Type of Reporting Person:
The aggregate amount in row (11) does not reflect shares of Common Stock held by the MSI Entities, as further described in Items 5(a) and 6. Percentages are based on 374,490,856 shares of Common Stock outstanding as of February 23, 2026, as reported in the Issuer's Form 10-K filed with the Securities and Exchange Commission on February 27, 2026.


SCHEDULE 13D


 
WR Berkley & Others LLC
 
Signature:/s/ W. Robert Berkley, Jr.
Name/Title:W. Robert Berkley, Jr. /Manager
Date:03/05/2026
 
WR Berkley & Others 2 LLC
 
Signature:/s/ W. Robert Berkley, Jr.
Name/Title:W. Robert Berkley, Jr. / Manager
Date:03/05/2026
 
William R. Berkley
 
Signature:/s/ William R. Berkley
Name/Title:William R. Berkley
Date:03/05/2026
 
Marjorie J. Berkley
 
Signature:/s/ Marjorie J. Berkley
Name/Title:Marjorie J. Berkley
Date:03/05/2026
 
W. Robert Berkley, Jr.
 
Signature:/s/ W. Robert Berkley, Jr.
Name/Title:W. Robert Berkley, Jr.
Date:03/05/2026
 
The William R. Berkley 2011 GST Trust u/a dated December 20, 2011
 
Signature:/s/ W. Robert Berkley, Jr.
Name/Title:W. Robert Berkley, Jr. /Trustee
Date:03/05/2026
 
The William R. Berkley 2022 Family Trust f/b/o William R. Berkley, Jr. and His Issue
 
Signature:/s/ Marjorie J. Berkley
Name/Title:Marjorie J. Berkley/Trustee
Date:03/05/2026
 
The William R. Berkley 2022 Family Trust f/b/o Lauren Berkley and Her Issue
 
Signature:/s/ Marjorie J. Berkley
Name/Title:Marjorie J. Berkley/Trustee
Date:03/05/2026

ATTACHMENTS / EXHIBITS

ATTACHMENTS / EXHIBITS

EX-99.3