SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 1)

W. R. BERKLEY CORPORATION

(Name of Issuer)

Common Stock, par value $0.20 per share

(Title of Class of Securities)

Attn: Kelly F. O'Donnell
WR Berkley & Others LLC, 475 Steamboat Road
Greenwich, CT, 06830
(203) 629-4800

Wachtell, Lipton, Rosen & Katz
Attention: David A. Katz, Esq., 51 West 52nd Street
New York, NY, 10019
(212) 403-1309

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

03/04/2026

(Date of Event Which Requires Filing of This Statement)

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. Checkbox not checked

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

CUSIP Number(s):

Name of reporting person

WR Berkley & Others LLC

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 63,515,547.00
8	Shared Voting Power 32,035,597.00
9	Sole Dispositive Power 63,515,547.00
10	Shared Dispositive Power 32,035,597.00

Aggregate amount beneficially owned by each reporting person

95,551,144.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox checked

Percent of class represented by amount in Row (11)

25.51 %

Type of Reporting Person (See Instructions)

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

CUSIP Number(s):

Name of reporting person

WR Berkley & Others 2 LLC

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 3,553,486.00
8	Shared Voting Power 91,997,658.00
9	Sole Dispositive Power 3,553,486.00
10	Shared Dispositive Power 91,997,658.00

Aggregate amount beneficially owned by each reporting person

95,551,144.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox checked

Percent of class represented by amount in Row (11)

25.51 %

Type of Reporting Person (See Instructions)

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

CUSIP Number(s):

Name of reporting person

William R. Berkley

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 17,363,285.00
8	Shared Voting Power 78,187,859.00
9	Sole Dispositive Power 17,363,285.00
10	Shared Dispositive Power 78,187,859.00

Aggregate amount beneficially owned by each reporting person

95,551,144.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox checked

Percent of class represented by amount in Row (11)

25.51 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

SCHEDULE 13D

CUSIP Number(s):

Name of reporting person

Marjorie J. Berkley

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 204,364.00
8	Shared Voting Power 95,346,780.00
9	Sole Dispositive Power 204,364.00
10	Shared Dispositive Power 95,346,780.00

Aggregate amount beneficially owned by each reporting person

95,551,144.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox checked

Percent of class represented by amount in Row (11)

25.51 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

SCHEDULE 13D

CUSIP Number(s):

Name of reporting person

W. Robert Berkley, Jr.

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 4,552,770.00
8	Shared Voting Power 90,998,374.00
9	Sole Dispositive Power 4,552,770.00
10	Shared Dispositive Power 90,998,374.00

Aggregate amount beneficially owned by each reporting person

95,551,144.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox checked

Percent of class represented by amount in Row (11)

25.51 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

SCHEDULE 13D

CUSIP Number(s):

Name of reporting person

The William R. Berkley 2011 GST Trust u/a dated December 20, 2011

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 1,350,000.00
8	Shared Voting Power 94,201,144.00
9	Sole Dispositive Power 1,350,000.00
10	Shared Dispositive Power 94,201,144.00

Aggregate amount beneficially owned by each reporting person

95,551,144.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox checked

Percent of class represented by amount in Row (11)

25.51 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

SCHEDULE 13D

CUSIP Number(s):

Name of reporting person

The William R. Berkley 2022 Family Trust f/b/o William R. Berkley, Jr. and His Issue

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 4,287,201.00
8	Shared Voting Power 91,263,943.00
9	Sole Dispositive Power 4,287,201.00
10	Shared Dispositive Power 91,263,943.00

Aggregate amount beneficially owned by each reporting person

95,551,144.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox checked

Percent of class represented by amount in Row (11)

25.51 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

SCHEDULE 13D

CUSIP Number(s):

Name of reporting person

The William R. Berkley 2022 Family Trust f/b/o Lauren Berkley and Her Issue

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 724,491.00
8	Shared Voting Power 94,826,653.00
9	Sole Dispositive Power 724,491.00
10	Shared Dispositive Power 94,826,653.00

Aggregate amount beneficially owned by each reporting person

95,551,144.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox checked

Percent of class represented by amount in Row (11)

25.51 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

SCHEDULE 13D

Item 1.

Security and Issuer

(a)

Title of Class of Securities:

Common Stock, par value $0.20 per share

(b)

Name of Issuer:

W. R. BERKLEY CORPORATION

(c)

Address of Issuer's Principal Executive Offices:

475 Steamboat Road, Greenwich, CONNECTICUT , 06830.

Item 1 Comment:

This Amendment No. 1 (this "Amendment No. 1") to Schedule 13D amends and supplements the statement on Schedule 13D filed with the United States Securities and Exchange Commission on December 5, 2025 (as it may be amended from time to time, collectively, the "Schedule 13D"), relating to W.R. Berkeley Corporation (the "Issuer"). Except as set forth herein, the Schedule 13D is unmodified. All capitalized terms contained herein but not otherwise defined shall have the meanings ascribed to such terms in the Schedule 13D. Information given in response to each item shall be deemed incorporated by reference in all other items, as applicable.

Item 2.

Identity and Background

(a)

The persons filing this Statement on Schedule 13D (this "Statement") are WR Berkley & Others LLC, a Delaware limited liability company ("Family Holdings"), WR Berkley & Others 2 LLC, a Delaware limited liability company ("Family Holdings 2"), William R. Berkley, Marjorie J. Berkley, W. Robert Berkley, Jr., The William R. Berkley 2011 GST Trust u/a dated December 20, 2011, The William R. Berkley 2022 Family Trust f/b/o William R. Berkley, Jr. and His Issue and The William R. Berkley 2022 Family Trust f/b/o Lauren Berkley and Her Issue (collectively, the "Reporting Persons"). Family Holdings is a Delaware limited liability company. The members of Family Holdings and Family Holdings 2 are William R. Berkley (direct owner of 16.7732% of each of the limited liability company interests thereof), WRB 2018 Irrevocable Family Trust dated as of September 4, 2018 (direct owner of each of 43.2268% of the limited liability company interests thereof) and WRB 2024 GRAT No. 1 dated as of November 19, 2024 (direct owner of 40.000% of the each of limited liability interest thereof). William R. Berkley is the trustee of WRB 2018 Irrevocable Family Trust dated as of September 4, 2018, and Marjorie J. Berkley is the trustee of WRB 2024 GRAT No. 1. The aggregate number of shares held by these three entities is expected to remain constant although there may be fluctuations in the holdings among the individual entities. William R. Berkley is the chairman of the Issuer's board of directors, is the spouse of Marjorie J. Berkley, and is the father of W. Robert Berkley, Jr (the chief executive officer of the Issuer). Marjorie J. Berkley is the spouse of William R. Berkley, and the mother of W. Robert Berkley, Jr.

(b)

The principal business address of each of the Reporting Persons is 475 Steamboat Road, Greenwich CT 06830.

(c)

Schedule A to this Statement includes the name, business address, present principal occupation or employment and citizenship of the managers of each of the Reporting Persons and is incorporated herein by reference.

(d)

During the last five years, none of the Reporting Persons nor any of their respective managers identified in Schedule A to this Statement has been convicted in a criminal proceeding (excluding traffic violations and similar misdemeanors).

(e)

During the last five years, none of the Reporting Persons nor any of their respective managers identified in Schedule A to this Statement was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

(f)

* WR Berkley & Others LLC is a Delaware limited liability company * WR Berkley & Others 2 LLC is a Delaware limited liability company * William R. Berkley, Marjorie J. Berkley and W. Robert Berkley, Jr are United States Citizens * The William R. Berkley 2011 GST Trust u/a dated December 20, 2011 is a trust organized under the laws of the state of Delaware * The William R. Berkley 2022 Family Trust f/b/o William R. Berkley, Jr. and His Issue The William R. Berkley 2022 Family Trust f/b/o Lauren Berkley and Her Issu are each trusts organized under the laws of the state of Florida.

Item 3.

Source and Amount of Funds or Other Consideration

The shares of Common Stock reported as beneficially owned by the Reporting Persons were acquired in or before the initial public offering of the Issuer, through open market purchases using personal funds, by means of gift, inheritance or other gratuitous transfer, or through their service as an officer, director or employee of the Issuer.

Item 4.

Purpose of Transaction

Item 4 is hereby amended by replacing the first paragraph with the following: Calculations of the Reporting Persons' beneficial ownership on the cover pages and in Item 5(a) of this Statement 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. However, when calculating MSI's percentage ownership for certain purposes under the Framework Agreement and LLC Agreement, MSI uses as its denominator 391,869,666 shares of Common Stock, which comprises such number of shares of Common Stock outstanding as of February 23, 2026 and 17,378,810 shares of Common Stock held in a grantor trust as of December 31, 2025, each as reported in the Issuer's Form 10-K filed with the Securities and Exchange Commission on February 27, 2026. We refer to that aggregate number as the "Outstanding Agreement Shares." Item 4 is hereby amended and supplemented by adding the following paragraph as the second to last paragraph of Item 4: In connection with MSI's acquisition of fifteen percent (15%) of the Outstanding Agreement Shares, MSI designated Andrew Carrier, an executive officer of MSI, to serve as a director of the Issuer. Mr. Carrier was nominated to the slate of directors up for election to the Issuer's Board at the Issuer's 2026 annual meeting by the Issuer's Board following the recommendation of the Issuer's Nominating and Corporate Governance Committee to the Board. Mr. Carrier is anticipated to be elected to the Board at the annual meeting of stockholders of the Issuer scheduled to be held in June 2026. Mr. Carrier was designated by MSI pursuant to the terms of the Framework Agreement.

Item 5.

Interest in Securities of the Issuer

(a)

Item 5(a) is amended and restated in its entirety as follows: The Reporting Persons beneficially own 95,551,144 shares of Common Stock, representing approximately 25.51% of the shares of Common Stock outstanding. The percentage beneficial ownership of the Reporting Persons has been determined based on 380,021,174 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. The beneficial ownership information set forth above does not include any securities of the Issuer beneficially owned by MSI. As a result of the Framework Agreement and LLC Agreement described in Item 6 of this Statement, the Reporting Persons may be deemed to beneficially own and share voting power over the shares of Common Stock beneficially owned by MSI. As of the date hereof, MSI beneficially owns an aggregate of 58,780,450 shares of Common Stock (representing approximately fifteen and seven-tenths percent 15.7% of the total number of shares of Common Stock outstanding). This Statement is not an admission or acknowledgment that the Reporting Persons constitute a "group" within the meaning of Rule 13d-5(b)(1) under the Act with MSI.

(b)

In addition to the description set forth above in Item 5(a), see the cover pages of this Statement for indications of the respective voting powers and disposition powers of the Reporting Persons.

(c)

None

(d)

Except as set forth herein, no one other than the Reporting Persons has the right to receive, or the power to direct the receipt of, dividends from, or the proceeds from the sale of, any of the securities of the Issuer beneficially owned by the Reporting Persons as described in this Item 5.

(e)

Not applicable.

Item 6.

Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer

Item 6 is hereby amended and supplemented by adding the following at the end of the second paragraph of the subsection entitled "Framework Agreement" in Item 6: The Closing Date is March 4, 2026. Item 6 is hereby amended and supplemented by adding the following paragraphs at the end of the subsection entitled "Limited Liability Company Agreement" in Item 6: The foregoing description of the LLC Agreement does not purport to be complete and is subject to, and qualified in its entirety by, the text of such agreement, which is attached hereto as Exhibit 99.3 and incorporated herein by reference.

Item 7.

Material to be Filed as Exhibits.

99.1 Joint Filing Agreement, dated December 11, 2025 (filed previously) 99.2 Framework Agreement (incorporated by reference to Exhibit 10.1 of the Current Report on Form 8-K filed by the Issuer on March 28, 2025) 99.3 Amended and Restated Limited Liability Company Agreement, dated March 4, 2026, by and among, Symphony Partners, LLC, Mitsui Sumitomo Insurance Co., Ltd. and WR Berkley & Others LLC

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

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

Amendment: SEC Form SCHEDULE 13D/A filed by W.R. Berkley Corporation