W. R. Berkley reports 8.9% stake in Quartzsea

W. R. Berkley Corporation, through subsidiary Berkley Insurance Company, reports beneficial ownership of Class A ordinary shares of Quartzsea Acquisition Corp. The group holds 900,000 Class A ordinary shares, representing 8.9% of this class.

Rhea-AI Filing Summary

W. R. Berkley Corporation, through subsidiary Berkley Insurance Company, reports beneficial ownership of Class A ordinary shares of Quartzsea Acquisition Corp. The group holds 900,000 Class A ordinary shares, representing 8.9% of this class.

The filing states no sole voting or dispositive power over these shares and shared voting and shared dispositive power over all 900,000 shares. Quartzsea Acquisition Corp’s principal executive offices are listed in New York, and W. R. Berkley Corporation’s principal business office is listed in Greenwich, Connecticut.

Key Figures

Beneficial ownership: 900,000 shares Percent of class: 8.9% Shared voting power: 900,000 shares +2 more

5 metrics

Beneficial ownership 900,000 shares Class A ordinary shares beneficially owned by W. R. Berkley Corporation

Percent of class 8.9% Percentage of Quartzsea Acquisition Corp Class A ordinary shares

Shared voting power 900,000 shares Shares over which there is shared power to vote or direct the vote

Shared dispositive power 900,000 shares Shares over which there is shared power to dispose or direct disposition

Par value $0.0001 per share Par value of Class A ordinary share of Quartzsea Acquisition Corp

Key Terms

beneficially owned, shared voting power, shared dispositive power, parent holding company, +1 more

5 terms

beneficially owned financial

"Item 4. | Ownership (a) | Amount beneficially owned: 900,00"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

shared voting power financial

"Shared Voting Power 900,000.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

shared dispositive power financial

"Shared Dispositive Power 900,000.00"

parent holding company financial

"If a parent holding company has filed this schedule, pursuant to (ii)(G)"

Schedule 13G regulatory

""Identification and Classification of the Subsidiary Which Acquired the Security Being Reported""

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What ownership stake in QSEA does W. R. Berkley Corporation report?

W. R. Berkley Corporation reports beneficial ownership of 900,000 Class A shares of Quartzsea Acquisition Corp, representing 8.9% of that class, with shared voting and dispositive power over all of these shares.

Who holds the Quartzsea Acquisition Corp (QSEA) shares for W. R. Berkley?

The filing identifies Berkley Insurance Company, a Delaware entity, as the subsidiary through which the 900,000 Class A shares of Quartzsea Acquisition Corp, or 8.9% of the class, are beneficially owned.

Does W. R. Berkley have sole voting power over its QSEA shares?

No. The filing lists 0 shares with sole voting power and 900,000 shares with shared voting power, matching the 8.9% beneficial ownership position in Quartzsea Acquisition Corp’s Class A shares.

What dispositive power does W. R. Berkley have over QSEA shares?

The Schedule 13G reports 0 shares with sole dispositive power and 900,000 shares with shared dispositive power, corresponding to 8.9% of Quartzsea Acquisition Corp’s outstanding Class A ordinary shares.

Where are Quartzsea Acquisition Corp (QSEA) and W. R. Berkley based?

Quartzsea Acquisition Corp’s principal executive offices are at 1185 Avenue of the Americas, New York, NY 10036. W. R. Berkley Corporation’s principal business office is at 475 Steamboat Road, Greenwich, CT 06830.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/06/2026 - 04:56 PM Accepted by SEC EDGAR 08/06/2026 - 04:56 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Quartzsea Acquisition Corp

(Name of Issuer)

Class A ordinary share, par value $0.0001 per share

(Title of Class of Securities)

G7314B104

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): G7314B104

1

Names of Reporting Persons

W. R. Berkley Corporation

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 900,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 900,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

900,000.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

8.9 %

12

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13G

CUSIP Number(s): G7314B104

1

Names of Reporting Persons

Berkley Insurance Company

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 900,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 900,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

900,000.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

8.9 %

12

Type of Reporting Person (See Instructions)

CO, IC

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Quartzsea Acquisition Corp
(b)	Address of issuer's principal executive offices: 1185 Avenue of the Americas, Suite 304, New York, New York, 10036
Item 2.
(a)	Name of person filing: W. R. Berkley Corporation
(b)	Address or principal business office or, if none, residence: 475 Steamboat Road Greenwich, CT 06830
(c)	Citizenship: US
(d)	Title of class of securities: Class A ordinary share, par value $0.0001 per share
(e)	CUSIP Number(s): G7314B104
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 900,00
(b)	Percent of class: 8.9 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 900,000
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 900,000
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. See Exhibit 99.1
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

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.

W. R. Berkley Corporation

Signature:	/s/ Richard M. Baio
Name/Title:	Richard M. Baio/Executive Vice President and Chief Financial Officer
Date:	08/05/2026

Berkley Insurance Company

Signature:	/s/ Richard M. Baio
Name/Title:	Richard M. Baio/Executive Vice President and Treasurer
Date:	08/05/2026