GigCapital9 Corp. 签署拟议业务合并的非约束性意向书

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 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): October 26, 2026

GigCapital9 Corp.

(Exact name of registrant as specified in its charter)

(650) 276-7040

(Registrant’s Telephone Number, Including Area Code)

Not Applicable

(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 of the registrant under any of the following provisions (see General Instructions 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. ☐

On October 26, 2026, GigCapital9 Corp. (the “Company”) issued a press release, which is attached as Exhibit 99.1 hereto, announcing that the Company has entered into a non-binding letter of intent (the “Letter of Intent”) for a business combination.

The completion of the proposed business combination is subject to the negotiation and execution of definitive documentation and satisfaction of customary closing conditions stated in the Letter of Intent, including (i) completion of any required stock exchange and regulatory review, (ii) approval of the transaction by the Company’s shareholders, and (iii) financing arrangements being secured. Accordingly, no assurances can be made that the parties will successfully negotiate and enter into a definitive agreement, or that the proposed transaction will be consummated on the terms or timeframe currently contemplated, or at all.

Additional Information and Where to Find It

If a definitive agreement is entered into in connection with the proposed business combination, a proxy statement/prospectus (the “GigCapital9 proxy statement/prospectus”) will be prepared and filed with the United States Securities and Exchange Commission (the “SEC”) and mailed to the Company’s shareholders. The Company urges investors and other interested persons to read, when available, the GigCapital9 proxy statement/prospectus, as well as other documents filed with the SEC, because these documents will contain important information about the proposed business combination. Such persons can also read the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025 (the “GigCapital9 Annual Report”), for a description of the security holdings of its officers and directors and their respective interests as security holders in the consummation of the transactions described herein. The GigCapital9 proxy statement/prospectus, once available, and the GigCapital9 Annual Report can be obtained, without charge, at the SEC’s website (http://www.sec.gov).

Participants in the Solicitation

The Company and its directors, executive officers, and certain other members of management and employees may be deemed participants in any solicitation of proxies from the Company’s shareholders in connection with the proposed transaction. Information regarding the Company’s directors and executive officers is contained in the Company’s filings with the SEC. Additional information regarding the interests of such participants in the proposed transaction, which may, in some cases, be different than those of the Company’s shareholders generally, will be included in any proxy statement, registration statement, prospectus, or other relevant documents filed with the SEC if and when such documents become available.

Forward-Looking Statements:

This Current Report on Form 8-K contains forward looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other applicable securities laws. Forward looking statements include, but are not limited to, statements regarding the proposed business combination contemplated by the Letter of Intent, the anticipated execution of definitive transaction agreements, the expected timing and completion of the proposed transaction, the potential future growth of the combined company, the anticipated benefits of the proposed transaction, and the future operating performance of the combined company. Forward looking statements generally may be identified by the use of words such as “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “forecast,” “intend,” “may,” “might,” “plan,” “potential,” “predict,” “project,” “seek,” “should,” “target,” “will,” “would,” and similar expressions, although not all forward looking statements contain such words. These forward‑looking statements are based on current expectations, estimates, forecasts, assumptions, and projections about future events and are subject to numerous risks and uncertainties, many of which are beyond the control of the Company. Actual results may differ materially from those expressed or implied by such forward looking statements as a result of a variety of factors, including, but not limited to: the risk that the parties may be unable to negotiate or execute definitive agreements relating to the proposed transaction; the risk that the proposed transaction may not be completed in a timely manner or at all; the failure to satisfy any conditions to closing; the failure to obtain required shareholder approvals, regulatory approvals, financing arrangements, exchange listing approvals, or other necessary consents; changes in applicable laws, regulations, governmental policies, or market conditions; the occurrence of any event, change, or circumstance that could delay, prevent, or otherwise adversely affect the proposed transaction; the ability to maintain the listing of securities on Nasdaq or another national securities exchange; redemptions by the

Company’s shareholders; the availability of financing; general economic, financial, political, and business conditions; inflation, interest rates, foreign exchange fluctuations, and geopolitical developments; cybersecurity incidents; intellectual property risks; litigation risks; competition; technological changes; the ability to realize anticipated benefits of the proposed transaction; and other risks and uncertainties that may be identified in any past or future filings made by the Company with the SEC. The proposed transaction is currently subject to a non-binding Letter of Intent. There can be no assurance that definitive agreements will be entered into, that the parties will successfully complete their due diligence, or that the proposed transaction will be completed on the terms currently contemplated, within the anticipated timeframe, or at all. Readers are cautioned not to place undue reliance on forward looking statements, which speak only as of the date of this Current Report on Form 8-K. The Company expressly disclaims any obligation or undertaking to update, revise, or publicly release any revisions to any forward-looking statements, whether as a result of new information, future events, changed circumstances, or otherwise, except as required by applicable law.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

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.