UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): September 23, 2026

Registrant’s telephone number, including area code: (203) 998-5540

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

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 Definitive Material Agreement.

The information included in Item 2.03 and Item 5.07 is incorporated by reference into this item to the extent required.

Item 2.03 Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

Effective as of September 23, 2026, Yawei Cao, the Chief Executive Officer of Cayson Acquisition Corp (the “Company”), loaned the Company an aggregate of $60,000. Such funds will be deposited into the trust account established by the Company in connection with its initial public offering pursuant to the Company’s Amended and Restated Memorandum and Articles of Association and trust agreement, as amended, governing the trust account in order to extend the time that the SPAC has to consummate an initial business combination (a “Business Combination”) as described below. The loan is evidenced by a promissory note (the “Note”) issued by the Company to Mr. Cao. The Note bears no interest and is repayable in full upon consummation of a Business Combination.

A copy of the Note is attached as Exhibit 10.1 to this Current Report on Form 8-K and is incorporated herein by reference. The disclosures set forth in this Item 2.03 are intended to be summaries only and are qualified in their entirety by reference to the Note.

Item 5.03. Amendments to Articles of Incorporation or Bylaws.

The information included in Item 5.07 is incorporated by reference into this item to the extent required.

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

On September 23, 2026, the Company held an extraordinary general meeting (the “Meeting”) to approve the following resolutions:

An aggregate of 4,216,565 ordinary shares of the Company, which represented a quorum of the outstanding ordinary shares entitled to vote as of the record date of September 1, 2026, were represented in person or by proxy at the Meeting.

The Company’s shareholders voted on the proposals at the Meeting, which were approved as follows:

Because quorum was obtained and the other proposals were approved, the Company did not hold a vote on the Adjournment Proposal.

The amendments to the Amended and Restated Memorandum and Articles of Association of the Company to be filed with the Cayman Islands Registrar of Companies to effectuate the foregoing are attached hereto as Exhibit 3.1. The Company will also amend that certain Investment Management Trust Agreement, dated September 19, 2024 and amended March 18, 2026, to effectuate the revised payment terms for the Extension adopted at the Meeting.

In connection with the Meeting, holders of an aggregate of 1,428,025 public shares of the Company exercised their right to have their shares redeemed for a pro rata amount held in the Company’s trust account.

The Company is continuing to seek to attempt to consummate an initial business combination.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

Cautionary Note Regarding Forward Looking Statements

Neither the Company nor any of its affiliates makes any representation or warranty as to the accuracy or completeness of the information contained in this Current Report on Form 8-K. This Current Report on Form 8-K is not intended to be all-inclusive and is not intended to form the basis of any investment decision or any other decision in respect of the Company or its proposed business combination.

This Current Report on Form 8-K include “forward-looking statements” made pursuant to the safe harbor provisions of the United States Private Securities Litigation Reform Act of 1995. Actual results may differ from expectations, estimates and projections and consequently, you should not rely on these forward-looking statements as predictions of future events. These forward-looking statements generally are identified by the words or phrases such as “aspire,” “expect,” “estimate,” “project,” “budget,” “forecast,” “anticipate,” “intend,” “plan,” “may,” “will,” “will be,” “will continue,” “will likely result,” “could,” “should,” “believe(s),” “predicts,” “potential,” “continue,” “future,” “opportunity,” seek,” “intend,” “strategy,” or the negative version of those words or phrases or similar expressions are intended to identify such forward-looking statements.

The Company cautions readers not to place undue reliance upon any forward-looking statements, which speak only as of the date made. The Company does not undertake or accept any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements to reflect any change in its expectations or any change in events, conditions or circumstances on which any such statement is based.

SIGNATURE

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.