Onconetix, Inc.

false 0001782107 0001782107 2026-04-30 2026-04-30 iso4217:USD xbrli:shares iso4217:USD xbrli:shares 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): April 30, 2026 Onconetix, Inc. (Exact name of registrant as specified in its charter) Delaware 001-41294 83-2262816 (State or other jurisdiction of incorporation) (Commission File Number) (IRS Employer Identification No.) 201 E. Fifth Street , Suite 1900 Cincinnati , Ohio 45202 (Address of principal executive offices) (Zip Code) Registrant’s telephone number, including area code: ( 513 ) 620-4101 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: ¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act: Title of each class Trading Symbol(s) Name of each exchange on which registered Common Stock, par value $0.00001 per share ONCO The Nasdaq Stock Market LLC 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 5.07 Submission of Matters to a Vote of Security Holders. On April 30, 2026, Onconetix, Inc. (the “ Compan y”) held a special meeting of stockholders (the “ Special Meeting ”). The matters voted on at the Special Meeting were: (1) the approval of an amendment to the Company’s Amended and Restated Certificate of Incorporation to effect one or more reverse stock splits of all of the outstanding shares of the Company’s common stock, par value $0.00001 per share (“ Common Stock ”), at a ratio in the range of 1-for-2 to 1-for-10, at any time prior to the one-year anniversary date of the special meeting, with such ratio to be determined by the Board of Directors without further approval or authorization of our stockholders, provided that the Company shall not effect reverse stock splits that, in the aggregate, exceed 1-for-100 (the “ Reverse Stock Split Proposal ”) (2) the approval the adjournment of the Special Meeting, if necessary or appropriate, to solicit additional proxies if there are insufficient votes at the time of the Special Meeting to approve the Reverse Stock Split Proposal. (the “ Adjournment Proposal ”) At the Special Meeting, all of the matters voted on were approved, based upon an aggregate of 3,464,686 shares of Common Stock outstanding as of March 13, 2026, the record date for the Special Meeting. The final voting results were as follows: 1. Reverse Stock Split Proposal The votes were cast for this matter as follows: Votes For Votes Against Abstentions 1,301,918 253,378 1,393 2. The Adjournment Proposal. The votes were cast for this matter as follows: Votes For Votes Against Abstentions 1,332,088 223,071 1,530 Item 9.01 Financial Statements and Exhibits. (d) Exhibits The following exhibits are being filed or furnished, as applicable, with this Current Report on Form 8-K: Exhibit No. Description 104 Cover Page Interactive Data File (embedded within the Inline XBRL document). 1 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. Onconetix, Inc. May 4, 2026 By: /s/ David Allan White Name: David Allan White Title: Chief Executive Officer 2