Quartzsea Acquisition Corp (0002047455) (Filer)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 13, 2026

Quartzsea Acquisition Corporation

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (212) 574-4425

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation to the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 1.01 Entry into a Material Definitive Agreement

On October 15, 2026, following shareholder approval at the Extraordinary General Meeting, the Company entered into Amendment No. 2 (the “Trust Amendment”) to the Investment Management Trust Agreement, dated March 17, 2025, as previously amended, with Continental Stock Transfer & Trust Company, as trustee.

The Trust Amendment permits corresponding monthly extensions through February 19, 2027, as described in Item 5.03 above. For each one-month extension, the Company must deposit into the trust account the lesser of $100,000 and $0.033 for each then-outstanding public ordinary share. It also requires disclosure of each monthly contribution on Form 8-K, provides a 30-day cure period for missed contributions before liquidation of the trust account, and prohibits modification of the extension terms during the extension period.

The foregoing description is qualified in its entirety by the Trust Amendment, filed as Exhibit 10.1 hereto and incorporated herein by reference.

Item 5.03 Amendments to Articles of Incorporation or Bylaws; change in Fiscal Year.

On October 15, 2026, the Company’s Second Amended and Restated Memorandum of Association became effective following shareholder approval at the Extraordinary General Meeting. It permits the Company to extend its deadline to consummate an initial business combination from October 19, 2026, on a month-to-month basis for up to four one-month extensions, with a final extended deadline of February 19, 2027, or such earlier date as the Company’s board of directors may determine.

The foregoing description is qualified in its entirety by the Second Amended and Restated Memorandum of Association, filed as Exhibit 3.1 hereto and incorporated herein by reference.

Item 5.07 Submission of a Matter to a Vote of Security Holders.

On October 13, 2026, Quartzsea Acquisition Corporation (the “Company”) held an Extraordinary General Meeting of Shareholders (the “Extraordinary General Meeting”). The record date for shareholders entitled to notice of, and to vote at, the Extraordinary General Meeting was September 22, 2026. As of the record date, there were 10,134,518 ordinary shares issued and outstanding and entitled to vote at the Extraordinary General Meeting. Of these shares, 8,411,452 shares (representing approximately 83.00% of the outstanding ordinary shares), constituting a quorum, were present by virtual attendance or represented by proxy.

At the Extraordinary General Meeting, three proposals were submitted to the Company’s shareholders, each as described in more detail in the Company’s definitive proxy statement. The final voting results were as follows:

Proposal 1 – Extension Amendment

The Company’s shareholders approved an amendment to the Company’s Second Amended and Restated Memorandum of Association extending the deadline to consummate an initial business combination from October 19, 2026, to February 19, 2027, or such earlier date as the Board of Directors may determine, with the Company permitted to extend such date on a month-to-month basis for up to four additional one-month extensions.

1

Proposal 2 – Trust Agreement Amendment

The Company’s shareholders approved a corresponding amendment to the Company’s Investment Management Trust Agreement, dated March 17, 2025, with Continental Stock Transfer & Trust Company, extending the trust termination date from October 19, 2026, to February 19, 2027, on the same month-to-month basis described above. For each one-month extension, the Company will deposit into the trust account the lesser of (i) $100,000 or (ii) $0.033 per outstanding public share.

Proposal 3 – Adjournment Proposal

The Company’s shareholders approved a Proposal to authorize the chairman of the Extraordinary General Meeting to adjourn to a later date or dates, if necessary, to permit further solicitation and voting of proxies if there were insufficient votes to approve Proposal 1 or Proposal 2.

All three Proposals were approved. The Company intends to file an amendment to its Second Amended and Restated Memorandum of Association with the Registrar of Companies of the Cayman Islands promptly following the Extraordinary General Meeting.

In connection with the Extraordinary General Meeting, holders of 3,344,937 ordinary shares exercised their right to redeem such shares at a redemption price of approximately $10.71 per share for an aggregate redemption amount of approximately $35.8 million. Following the redemptions, 3,659,681 public ordinary shares remain outstanding.

Item 9.01. Financial Statements and Exhibits.

2

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

3