# EDGAR Filing Document

**Accession Number:** 0001782107
**File Stem:** 0001213900-26-058997
**Filing Date:** 2026-5
**Character Count:** 17989
**Document Hash:** ce842f1d02b79033e1e117266e973ec1
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001213900-26-058997.hdr.sgml**: 20260519

**ACCESSION NUMBER**: 0001213900-26-058997

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 14

**CONFORMED PERIOD OF REPORT**: 20260519

**ITEM INFORMATION**: Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20260519

**DATE AS OF CHANGE**: 20260519

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Onconetix, Inc.
- **CENTRAL INDEX KEY:** 0001782107
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-41294
- **FILM NUMBER:** 26998603

**BUSINESS ADDRESS:**
- **STREET 1:** 201 E. FIFTH STREET
- **STREET 2:** SUITE 1900
- **CITY:** CINCINNATI
- **STATE:** OH
- **ZIP:** 45202
- **BUSINESS PHONE:** 513-620-4101

**MAIL ADDRESS:**
- **STREET 1:** 201 E. FIFTH STREET
- **STREET 2:** SUITE 1900
- **CITY:** CINCINNATI
- **STATE:** OH
- **ZIP:** 45202

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Blue Water Biotech, Inc.
- **DATE OF NAME CHANGE:** 20230424

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Blue Water Vaccines Inc.
- **DATE OF NAME CHANGE:** 20190710

?xml version='1.0' encoding='ASCII'?

**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): May 19, 2026**

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| |
|:---|
| **Onconetix, Inc.** |
| **(Exact name of registrant as specified in its charter)** |

---

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| | | |
|:---|:---|:---|
| **Delaware** | **001-41294** | **83-2262816** |
| (State or other jurisdiction<br> of incorporation) | (Commission File Number) | (IRS Employer <br> Identification No.) |

---

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| | |
|:---|:---|
| **201 E. Fifth Street** **, Suite 1900**<br> **Cincinnati** **, Ohio** | **45202** |
| **(Address of principal executive offices)** | **(Zip Code)** |

---

**Registrant's telephone number, including area code: (513) 620-4101**

**<u>Not Applicable</u>**

(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:

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| | | |
|:---|:---|:---|
| 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 |

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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 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.**

As previously reported on a Current Report on Form 8-K filed on May 4, 2026, Onconetix, Inc. (the "Company") held a special meeting of stockholders (the "Special Meeting") on April 30, 2026. At the Special Meeting, the Company's stockholders approved the proposal to grant discretionary authority to the Company's Board of Directors (the "Board") to amend the Company's Amended and Restated Certificate of Incorporation, as amended to date (the "Charter"), in order to effect reverse stock splits of all of the outstanding shares of its issued and outstanding common stock, par value $0.00001 (the "Common Stock"), at a ratio in the range of one-for-two (1:2) to one-for-ten (1:10) at any time prior to the one-year anniversary date of the Special Meeting, with such ratio to be determined by the Board, provided that the Company shall not effect reverse stock splits that, in the aggregate, exceed 1-for-100 (the "Reverse Stock Split Proposal").

On May 8, 2026, the Board determined to fix a reverse stock split ratio of its Common Stock of 1-for-10 (the "Reverse Stock Split"). On May 20, 2026, the Company expects to file an amendment to its Charter with the Secretary of State of the State of Delaware (the "Amendment") to effect the Reverse Stock Split. The Reverse Stock Split will become effective in accordance with the terms of the Amendment at 12:01 a.m. Eastern Time on May 21, 2026 (the "Effective Time"). The Company's Common Stock will begin trading on a split-adjusted basis when the Nasdaq Stock Market opens on May 21, 2026 under the symbol ONCO, under a new CUSIP number, 68237Q 401. The Reverse Stock Split is primarily intended to bring the Company into compliance with The Nasdaq Stock Market, LLC's rule on minimum bid price requirements.

At the Effective Time, every 10 (ten) shares of the Company's issued and outstanding Common Stock will convert automatically into one (1) issued and outstanding share of Common Stock, with no corresponding reduction in the number of authorized shares of Common Stock, and without any change in the par value per share. Stockholders holding shares through a brokerage account will have their shares automatically adjusted to reflect the 1-for-10 Reverse Stock Split. It is not necessary for stockholders holding shares of the Common Stock in certificated form to exchange their existing stock certificates for new stock certificates of the Company in connection with the Reverse Stock Split, although stockholders may do so if they wish.

The Reverse Stock Split will affect all stockholders uniformly and will not alter any stockholder's percentage interest in the Company's equity, except to the extent that the Reverse Stock Split would result in a stockholder owning a fractional share. No fractional shares will be issued in connection with the Reverse Stock Split. Stockholders who would otherwise be entitled to receive a fractional share will instead receive a cash payment (without interest) equal to such fraction multiplied by the closing sale price per share of the Common Stock on The Nasdaq Capital Market at the close of business on the date prior to the effective date of the Reverse Stock Split, or May 20, 2026 (with such closing sale price being adjusted to give effect to the Reverse Stock Split). The Reverse Stock Split will reduce the number of outstanding shares of the Company's common stock from approximately 11.4 million to approximately 1.14 million.

Proportional adjustments will be made to the number of shares of Common Stock issuable upon exercise or conversion of the Company's equity awards, convertible preferred stock and warrants, as well as the applicable exercise price. Stockholders with shares in brokerage accounts should direct any questions concerning the Reverse Stock Split to their broker; all other stockholders may direct questions to the Company's transfer agent, Continental Stock Transfer & Trust Company, at 212-509-4000.

The foregoing description of the Amendment does not purport to be complete and is qualified in its entirety by reference to the full text of the Amendment, which is filed as Exhibit 3.1 to this Current Report on Form 8-K and incorporated by reference herein.

**Item 8.01 Other Events.**

On May 19, 2026, the Company issued a press release announcing the Reverse Stock Split, a copy of which is filed as Exhibit 99.1 to this Current Report on Form 8-K.

**Item 9.01 Financial Statements and Exhibits.**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) <u>Exhibits</u>

The following exhibits are being filed or furnished, as applicable, with this Current Report on Form 8-K:

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| | |
|:---|:---|
| **Exhibit No.** | **Description** |
| 3.1 | [Certificate of Amendment to the Amended and Restated Certificate of Incorporation, as amended, of Onconetix, Inc.](ea029154301ex3-1.htm) |
| 99.1 | [Press Release, dated May 19, 2026.](ea029154301ex99-1.htm) |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document). |

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**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.

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| | | |
|:---|:---|:---|
|  | **Onconetix, Inc.** | **Onconetix, Inc.** |
| May 19, 2026 | By: | */s/ David Allan White* |
|  | Name: | David Allan White |
|  | Title: | Chief Executive Officer |

---

## Exhibit 3.1

**Exhibit 3.1**

**CERTIFICATE OF AMENDMENT<br> OF CERTIFICATE OF INCORPORATION<br> OF ONCONETIX, INC.**

Onconetix, Inc., a corporation organized and existing under the laws of the State of Delaware (the "Corporation"), does hereby certify as follows:

1. The name of the Corporation is Onconetix, Inc.

2. The Certificate of Incorporation of the Corporation is amended by adding the following new paragraph to the end of Article IV, Section D:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6. Upon the filing and effectiveness (the "***Effective Time***") of this amendment to the Corporation's Certificate of Incorporation, as amended, pursuant to the Delaware General Corporation Law, each ten (10) shares of the Common Stock issued immediately prior to the Effective Time (the "***Old Common Stock***") shall be reclassified and combined into one validly issued, fully paid and non-assessable share of the Corporation's Common Stock, $0.00001 par value per share (the "***New Common Stock***"), without any action by the holder thereof (the "***Reverse Stock Split***"). No fractional shares of New Common Stock shall be issued as a result of the Reverse Stock Split and, in lieu thereof, upon surrender after the Effective Time of a book entry position which formerly represented shares of Old Common Stock that were issued and outstanding immediately prior to the Effective Time, any person who would otherwise be entitled to a fractional share of New Common Stock as a result of the Reverse Stock Split, following the Effective Time, shall be entitled to receive a cash payment equal to the fraction of a share of New Common Stock to which such holder would otherwise be entitled multiplied by the closing price per share of the New Common Stock on The Nasdaq Stock Market LLC at the close of business on the date prior to the Effective Time. Each book entry position that theretofore represented shares of Old Common Stock shall thereafter represent that number of shares of New Common Stock into which the shares of Old Common Stock represented by such book entry position shall have been reclassified and combined; provided, that each person holding of record a book entry position that represented shares of Old Common Stock shall receive, a new book entry position evidencing and representing the number of shares of New Common Stock to which such person is entitled under the foregoing reclassification and combination.

3. This Certificate of Amendment has been duly adopted by the Board of Directors and stockholders of the Corporation in accordance with Section 242 of the General Corporation Law of the State of Delaware.

4. This Certificate of Amendment shall become effective as of 12:01 a.m., Eastern Time on May 21, 2026.

IN WITNESS WHEREOF, the Corporation has caused this Certificate of Amendment to be duly executed in its corporate name as of the 20<sup>th</sup> day of May 2026.

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| | |
|:---|:---|
| By | /s/ David Allan White |
|  | David Allan White |
|  | Chief Executive Officer |

---

## Exhibit 99.1

**Exhibit 99.1**

![](ea029154301ex99-1img1.jpg)

**Onconetix, Inc. Announces 1-for-10 Reverse Stock Split**

CINCINNATI, Ohio, May 19, 2026 (GLOBE NEWSWIRE) — Onconetix, Inc. (NASDAQ: ONCO) ("Onconetix" or the "Company"), a commercial-stage biotechnology company focused on the research, development, and commercialization of innovative solutions for oncology, today announced that its Board of Directors (the "Board of Directors" or "Board") has approved a 1-for-10 reverse stock split of its outstanding shares of common stock, to be effective as of 12:01 a.m. Eastern Time on May 21, 2026.

On April 30, 2026, Onconetix held a special meeting of stockholders (the "Special Meeting"), at which the Company's stockholders approved a proposal to effect one or more reverse splits, 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 without further approval or authorization of the stockholders, provided that the Company shall not effect reverse stock splits that, in the aggregate, exceed 1-for-100. Since the receipt of such stockholder approval, the Company's Board of Directors has determined to fix a split ratio of 1-for-10 shares. The Company's common stock will begin trading on a reverse stock split-adjusted basis at the opening of the market on May 21, 2026. Following the reverse stock split, the Company's common stock will continue to trade on The Nasdaq Capital Market under the symbol "ONCO" under the new CUSIP number 68237Q 401. The reverse stock split is intended to enable the Company to maintain compliance with the minimum bid price requirement of $1.00 per share of common stock for continued listing on The Nasdaq Capital Market.

At the effective time of the reverse split, every 10 issued and outstanding shares of the Company's common stock will be converted automatically into one share of the Company's common stock without any change in the par value per share. No fractional shares will be issued in connection with the reverse stock split, and fractional shares resulting from the reverse stock split will be canceled with the holders thereof receiving cash compensation. The amount of compensation will be determined by multiplying the fractional share by the closing price per share of the Company's common stock on The Nasdaq Capital Market at the close of business on the trading day prior to the effective date of the reserve stock split, or May 21, 2026. The reverse split will have no effect on the number of authorized shares of the Company's common stock, and the ownership percentage of each stockholder will remain unchanged other than as a result of fractional shares. The reverse stock split will additionally apply to the Company's common stock issuable upon exercise or conversion of the Company's equity awards, convertible preferred stock and warrants, as well as the applicable exercise price.

The reverse stock split will reduce the number of outstanding shares of the Company's common stock from approximately 11.4 million to approximately 1.14 million.

**About Onconetix, Inc.**

Onconetix (Nasdaq: ONCO) is a commercial stage biotechnology company focused on the research, development and commercialization of innovative solutions. Onconetix owns Proclarix®, an in vitro diagnostic test for prostate cancer originally developed by Proteomedix and approved for sale in the European Union ("EU") under the IVDR, which it anticipates will be marketed in the U.S. as a lab developed test ("LDT") through its license agreement with Labcorp. For more information, visit www.onconetix.com.

**Forward-Looking Statements**

*Certain statements in this press release are forward-looking within the meaning of the Private Securities Litigation Reform Act of 1995. These statements may be identified by the use of forward-looking words such as "anticipate," "believe," "forecast," "estimate," "expect," and "intend," among others. These forward-looking statements (including, without limitation, statements regarding the timing and effectiveness of the anticipated reverse split and compliance with applicable Nasdaq continued listing requirements) are based on Onconetix's current expectations and actual results could differ materially. There are a number of factors that could cause actual events to differ materially from those indicated by such forward-looking statements. These factors include, but are not limited to, market and other conditions; and our ability to comply with the continued listing requirements of, and remain trading on, the Nasdaq Stock Market, LLC*. *As with any commercial-stage pharmaceutical product or any product candidate under clinical development, there are significant risks in the development, regulatory approval and commercialization of biotechnology products. Onconetix does not undertake an obligation to update or revise any forward-looking statement. Investors should read the risk factors set forth in Onconetix's Annual Report on Form 10-K, filed with the SEC on March 13, 2026 and periodic reports filed with the SEC on or after the date thereof. All of Onconetix's forward-looking statements are expressly qualified by all such risk factors and other cautionary statements. The information set forth herein speaks only as of the date thereof.*

**For more information:**

Onconetix, Inc.<br> 201 E. Fifth Street, Suite 1900<br> Cincinnati, OH 45202<br> Phone: (513) 620-4101

**Investor Contact Information:**

Onconetix Investor Relations<br> Email: investors@onconetix.com