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): December 18, 2025 (December 16, 2025)

IRON HORSE ACQUISITION II CORP.

(Exact name of registrant as specified in its charter)

851 Broken Sound Parkway Nw

Boca Raton, FL 33487

(Address of principal executive offices, including zip code)

(310) 290-5383

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:

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 December 16, 2025, the registration statement (File No. 333-284331), as amended (the “Registration Statement”), relating to the initial public offering (“IPO”) of Iron Horse Acquisition II Corp. (the “Company”) was declared effective by the Securities and Exchange Commission (the “Commission”).

On December 18, 2025, the Company consummated the IPO, which consisted of 23,000,000 units (the “Units”), including the exercise in full by the underwriters of an option to purchase up to 3,000,000 Units at the offering price to cover over-allotments. Each Unit consists of one ordinary share of the Company, par value $0.0001 per share (“Shares”), and one right (each, a “right”). Each right entitles the holder thereof to receive one-tenth (1/10) of a Share upon the consummation of an initial business combination. The Units were sold at a price of $10.00 per Unit, generating gross proceeds to the Company of $230,000,000.

In connection with the IPO, the Company entered into the following agreements, forms of which were previously filed as exhibits to the Company’s Registration Statement on Form S-1 (File No. 333-284331) related to the IPO:

Item 3.02. Unregistered Sales of Equity Securities.

Simultaneously with the closing of the IPO, the Company completed the private sale of an aggregate of 570,000 private placement units (the “Private Units”), at a purchase price of $10.00 per Private Unit, of which 370,000 Private Units were sold to the Sponsor and 200,000 Private Units were sold to Cantor, generating gross proceeds to the Company of $5,700,000. The Private Units are identical to the public Units sold in the IPO, except as otherwise disclosed in the Registration Statement. No underwriting discounts or commissions were paid with respect to such sale. The issuance of the Private Units was made pursuant to the exemption from registration contained in Section 4(a)(2) of the Securities Act of 1933, as amended.

Item 5.03. Amendments to Certificate of Incorporation or Bylaws; Change in Fiscal Year.

On December 16, 2025, in connection with the IPO, the Company filed its Amended and Restated Memorandum and Articles of Association. A copy of the Amended and Restated Memorandum and Articles of Association is attached as Exhibit 3.1 hereto and incorporated herein by reference.

Item 8.01. Other Events.

A total of $230,000,000 was placed in a U.S.-based trust account maintained by Continental Stock Transfer & Trust Company, acting as trustee. Except with respect to interest earned on the funds held in the trust account that may be released to the Company to pay its taxes, the funds held in the trust account will not be released from the trust account until the earliest of (i) the completion of the Company’s initial business combination, (ii) the redemption of any of the Company’s public shares properly submitted in connection with a shareholder vote to amend the Company’s second amended and restated certificate of incorporation (a) to modify the substance or timing of its obligation to redeem 100% of the Company’s public shares if it does not complete its initial business combination within 24 months (the “Combination Period”) from the closing of the IPO or (b) with respect to any other provision relating to stockholders’ rights or pre-initial business combination activity and (iii) the redemption of the Company’s public shares if it is unable to complete its initial business combination within the Combination Period, subject to applicable law.

On December 16, 2025, the Company issued a press release announcing the pricing of the IPO, a copy of which is attached as Exhibit 99.1 to this Current Report on Form 8-K.

On December 18, 2025, the Company issued a press release announcing the closing of the IPO, a copy of which is attached as Exhibit 99.2 to this Current Report on Form 8-K.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

The following exhibits are being filed herewith:

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.

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