AXT Inc

Item 1.01 Entry into a Material Definitive Agreement. Underwriting Agreement On April 21, 2026, AXT, Inc., a Delaware corporation (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with Northland Securities, Inc., as representative of the underwriters named therein (the “Underwriters”) related to the offer and sale of shares of the Company’s common stock (the “Offering”). The Underwriting Agreement provides for the offer and sale by the Company, and the purchase by the Underwriters, of 8,560,311 shares of the Company’s common stock (the “Base Shares”) at a price to the public of $64.25 per share. Pursuant to the Underwriting Agreement, the Company granted the Underwriters a 30-day option to purchase up to 1,284,046 additional shares of common stock (the “Option Shares” and, together with the Base Shares, the “Shares”) at the public offering price. The Offering is anticipated to close on April 22, 2026 (the “Closing Date”), subject to customary closing conditions. The gross proceeds to the Company from the Offering for the Base Shares are expected to be approximately $550 million, before deducting underwriting discounts and commissions and other offering expenses. If the Option Shares are fully exercised, the Company expects to receive aggregate gross proceeds of approximately $632.5 million, before deducting underwriting discounts and commissions and other offering expenses. Northland Securities, Inc. is acting as sole bookrunner for the Offering. Needham & Company, B. Riley Securities, Craig-Hallum Capital Group LLC and Wedbush Securities Inc. are acting as co-managers for the Offering. The Company intends to use the net proceeds from the Offering primarily to financially support its subsidiary Beijing Tongmei Xtal Technology Co., Ltd. in its efforts to increase its capacity to produce indium phosphide substrates for export worldwide, for research and development of new or improved products, and for working capital and general corporate purposes. The Underwriting Agreement contains representations, warranties and agreements by the Company, customary conditions to closing, indemnification obligations of the Company, including for liabilities arising under the Securities Act of 1933, as amended (the “Securities Act”), as well as other obligations of the parties and termination provisions. The representations, warranties and covenants contained in the Underwriting Agreement were made only for the purposes of such agreements and as of the specific dates, were solely for the benefit of the parties to such agreements and may be subject to limitations agreed upon by the contracting parties. The Shares are being sold pursuant to the Company’s automatic shelf registration statement on Form S-3 (Registration Statement No. 333-295188), which became effective on April 20, 2026, with the Securities and Exchange Commission pursuant to Rule 462(e) of the Securities Act, including the base prospectus contained therein, and the prospectus supplement dated April 21, 2026 to be filed with the Commission on April 21, 2026 (the “Prospectus Supplement”). Lock-Up Agreement Each of the Company’s executive officers and directors has entered into a lock-up agreement (the “Lock-Up Agreement”) pursuant to which each has agreed, subject to certain exceptions set forth therein, not to dispose of or hedge any shares of common stock of the Company or securities convertible into or exchangeable for shares of common stock during the period from the date of the Lock-Up Agreement continuing through the close of business sixty (60) days after the date of the Prospectus Supplement. The foregoing descriptions of the Underwriting Agreement and the Lock-Up Agreement do not purport to be complete and are qualified in their entirety by the full texts of the Underwriting Agreement and the form of the Lock-Up Agreement, copies of which are attached hereto as Exhibit 1.1 and Exhibit 10.1, respectively, and are incorporated by reference herein. A copy of the legal opinion issued by the Company’s legal counsel relating to certain legal matters in connection with the Offering and the validity of the securities offered by the Prospectus Supplement is filed as Exhibit 5.1 to this Current Report and incorporated by reference into the Prospectus Supplement. This Current Report on Form 8-K does not constitute an offer to sell any securities or a solicitation of an offer to buy any securities, nor shall there be any sale of any securities in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

Item 8.01 Other Events . Press Releases On April 20, 2026, the Company issued a press release announcing the launch of the Offering, a copy of which is furnished as Exhibit 99.1 to this Form 8-K. On April 21, 2026, the Company issued a press release announcing the pricing of the Offering, a copy of which is furnished as Exhibit 99.2 to this Form 8-K.