# EDGAR Filing Document

**Accession Number:** 0002006260
**File Stem:** 0001415889-25-019830
**Filing Date:** 2025-7
**Character Count:** 10961
**Document Hash:** 600aecfefee07daa8acfe0755c69f2dd
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001415889-25-019830.hdr.sgml**: 20250716

**ACCESSION NUMBER**: 0001415889-25-019830

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20250716

**DATE AS OF CHANGE**: 20250716

**SUBJECT COMPANY**: 

**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:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-93586
- **FILM NUMBER:** 251127390

**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
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Altos Venture AG
- **CENTRAL INDEX KEY:** 0002006260

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** V8
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**BUSINESS ADDRESS:**
- **STREET 1:** OBERTORWEG 64
- **CITY:** ALLSCHWIL
- **STATE:** V8
- **ZIP:** CH-4123
- **BUSINESS PHONE:** 41 61 481 8663

**MAIL ADDRESS:**
- **STREET 1:** OBERTORWEG 64
- **CITY:** ALLSCHWIL
- **STATE:** V8
- **ZIP:** CH-4123

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 1)**

**ONCONETIX, INC.**

*(Name of Issuer)*

**Common Stock, par value $0.00001 per share**

*(Title of Class of Securities)*

**68237Q203**

*(CUSIP Number)*

**Tobias Fischli**<br>25616 Moody Road<br>Los Altos Hills CA 94022<br>(415) 515-8417

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**07/14/2025**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **68237Q203** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Altos Venture AG** | Name of reporting person<br>**Altos Venture AG** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**V8** | Citizenship or place of organization<br>**V8** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**273230.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**273230.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**273230.00** | Aggregate amount beneficially owned by each reporting person<br>**273230.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**35.8%** | Percent of class represented by amount in Row (11)<br>**35.8%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** Item 13 percentage is calculated based on approximately 521,863 shares of Common Stock of the Issuer outstanding as of June 13, 2025, as reported in the Issuer's Current Report on Form 8-K filed with the Securities and Exchange Commission (the "SEC") on June 11, 2025, after giving effect to the issuance of 241,514 shares to the Reporting Person on July 14, 2025.

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock, par value $0.00001 per share

**(b) Name of Issuer:**
ONCONETIX, INC.

**(c) Address of Issuer's Principal Executive Offices:**
201 E. Fifth Street, Suite 1900, Cincinnati, OH, 45202

The class of equity security to which this statement on Schedule 13D relates is the Common Stock, $0.00001 par value ("Common Stock"), of Onconetix, Inc., a Delaware corporation (the "Issuer"). On September 24, 2024, the issuer effected a 1-for-40 reverse split of its Common Stock, and on June 13, 2025, the issuer effected a 1-for-85 reverse split of its Common Stock. In this report, numbers of shares of Common Stock (and related per-share amounts) prior to the reverse splits have been adjusted to give retroactive effect to the reverse splits.

Information given in response to each item shall be deemed incorporated by reference in all other items, as applicable.

**Item 4. Purpose of Transaction**

The Reporting Person purchased the aforementioned securities for investment purposes with the aim of increasing the value of its investments and the Issuer. Subject to applicable legal requirements, the Reporting Person may purchase additional securities of the Issuer from time to time in open market or private transactions, depending on its evaluation of the Issuer's business, prospects and financial condition, the market for the Issuer's securities, other developments concerning the Issuer, the reaction of the Issuer to the Reporting Person's ownership of the Issuer's securities, other opportunities available to the Reporting Person, and general economic, money market and stock market conditions. In addition, depending upon the factors referred to above, the Reporting Person may dispose of all or a portion of its securities of the Issuer at any time (including by means of programs adopted pursuant to Rule 10b5-1 under the Securities Exchange Act of 1934 (the "Act")). The Reporting Person reserves the right to increase or decrease its holdings on such terms and at such times as it may decide.

Except as set forth in this Item 4 and Item 6 below, the Reporting Person has no present plan or proposal that relates to or would result in any of the actions specified in clauses (a) through (j) of Item 4 of Schedule 13D of the Act. However, the Reporting Person reserves the right to propose or participate in future transactions which may result in one or more of such actions, including but not limited to, an extraordinary corporate transaction, such as a merger, reorganization or liquidation, sale of a material amount of assets of the Issuer or its subsidiaries, or other transactions that might have the effect of causing the Common Stock to become eligible for termination of registration under Section 12(g) of the Act. The Reporting Person also retains the right to change its investment intent at any time, to acquire additional shares of Common Stock or other securities of the Issuer from time to time, or to sell or otherwise dispose of all or part of the Common Stock beneficially owned by it (or any shares of Common Stock into which such securities are converted) in any manner permitted by law. The Reporting Person may engage from time to time in ordinary course transactions with financial institutions with respect to the securities described herein.

**Item 5. Interest in Securities of the Issuer**

**(a)**
As of the date hereof, the Reporting Person is the record owner of 273,230 shares of Common Stock, representing approximately 35.8% of the outstanding Common Stock on June 13, 2025, as reported in the Issuer's Current Report on Form 8-K filed with the SEC on June 11, 2025, after giving effect to the issuance of 241,514 shares to the Reporting Person on July 14, 2025.

**(b)**
The Reporting Person has the sole power to vote or to direct the vote and the sole power to dispose of or to direct the disposition of the Issuer's securities identified in paragraph (a) above.

**(c)**
Except as set forth in Item 3 above, the Reporting Person have not effected any transactions in the securities of the Issuer in the last 60 days.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

Lock-Up Agreement
Concurrently with the execution of the Share Exchange Agreement, the Sellers (including the Reporting Party) and certain other parties, as shareholders of Proteomedix, entered into Lock-Up Agreements (each, a "Lock-Up Agreement"). Pursuant to each Lock-Up Agreement, each signatory thereto agrees not to, during the period commencing December 15, 2023 and ending on the earlier of December 31, 2024 and the 6-month anniversary of the date of stockholder approval of the issuance of Common Stock upon conversion of the Convertible Preferred Stock (and other matters): (i) lend, offer, pledge, hypothecate, encumber, donate, assign, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, or otherwise transfer or dispose of, directly or indirectly, the shares of Common stock issued pursuant to the Share Exchange Agreement or upon conversion of the Convertible Preferred Stock, (ii) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of such shares, or (iii) publicly disclose the intention to do any of the foregoing, whether any such transaction described in clauses (i), (ii) or (iii) above is to be settled by delivery of such shares or other securities, in cash or otherwise (subject to certain exceptions).

The foregoing description of the Lock-Up Agreements does not purport to be complete and is qualified in its entirety by reference to the form of the Lock-Up Agreement, the form of which is filed as Exhibit C and is incorporated herein by reference.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Altos Venture AG

**Signature:** /s/ Tobias Fischli

**Name/Title:** Tobias Fischli, Authorized Signatory

**Date:** 07/16/2025