Artius II Acquisition Inc.

Item 1.01. Entry into a Material Definitive Agreement. Working Capital Promissory Note On March 6, 2026, Artius II Acquisition Inc. (the “Company”) issued a convertible unsecured promissory note (the “Working Capital Promissory Note”) in the aggregate principal amount of up to $1,000,000.00 to Artius II Acquisition Partners LLC, a Delaware limited liability company (the “Sponsor”), in order to provide the Company with additional working capital. Pursuant to the terms of the Working Capital Promissory Note, the principal balance shall not accrue interest and will be payable by the Company upon the earlier of (i) the date on which the Company consummates its initial business combination, (ii) the date on which the Company is liquidated or (iii) the date on which an Event of Default (as defined in the Working Capital Promissory Note) occurs and will be convertible, at the Sponsor’s election, to Class A ordinary shares, par value $0.0001 (or the equivalent thereof) of the Company or the surviving company of the Company’s initial business combination (each, a “Private Placement Share”) upon the earlier of (i) the date on which the Company consummates its initial business combination, (ii) the date on which the Company is liquidated or (iii) the date on which an Event of Default (as defined in the Working Capital Promissory Note) occurs. The number of Private Placement Shares issued upon conversion will be equal to (x) the unpaid principal amount of the Working Capital Promissory Note, divided by (y) $10.00, multiplied by (z) 1.1, rounded up to the nearest whole number of shares. The foregoing description of the Working Capital Promissory Note does not purport to be complete and is qualified in its entirety by reference to the full text of the Working Capital Promissory Note, which is filed hereto as Exhibit 10.1 and which is incorporated herein by reference.

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information disclosed under Item 1.01 of this Current Report on Form 8-K is incorporated by reference into this Item 2.03.

Item 3.01 Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing. On March 4, 2026, the Company received a notice (the “Notice”) from The Nasdaq Stock Market LLC (“Nasdaq”) indicating that the Company was not in compliance with Nasdaq’s Listing Rule 5452(a)(2)(A) because the Company failed to maintain a minimum of 300 public holders of its units and Class A ordinary shares listed on The Nasdaq Global Market, as required under the Nasdaq continued listing standards for The Nasdaq Global Market. The Notice has no immediate effect on the listing of the Company’s securities on Nasdaq. Under Nasdaq Listing Rules, the Company has 45 calendar days to submit a plan to regain compliance with Listing Rule 5452(a) and may be granted up to 180 calendar days from the date of the Notice to regain compliance therewith. The Company plans to submit its plan of compliance to Nasdaq within the required timeframe.

Item 3.02. Unregistered Sales of Equity Securities. The information disclosed under Item 1.01 of this Current Report on Form 8-K is incorporated by reference into this Item 3.02. The Company has relied upon Section 4(a)(2) of the Securities Act of 1933, as amended, in connection with the issuance of the Working Capital Promissory Note.