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ONCO 424B3: Secondary offering

Onconetix, Inc.

Filed with the SEC on · accession 0001213900-26-098126

ONCO filed a 424B3 (prospectus (offering)) with the SEC on Sep 8, 2026. Onconetix, Inc. filed a prospectus for the resale of up to 100,000,000 shares of common stock by a selling stockholder, representing 2,282% of outstanding shares as of August 28, 2026. The stock moved -17.6% by the first close after the filing.

Summary of the filing

Onconetix, Inc. filed a prospectus for the resale of up to 100,000,000 shares of common stock by a selling stockholder, representing 2,282% of outstanding shares as of August 28, 2026. The shares are issuable upon conversion of Series F preferred stock issued in a private placement that closed on July 29, 2026.

For details, click here →How to read a 424B3 →

Key details

Shares of common stock registered for resale$100.0M
Aggregate purchase price of Series F preferred stock$30.2M
Initial conversion price per share$1
Last reported sale price on August 28, 2026$1
IssuerOnconetix, Inc.
UnderwriterSeven Knots LLC

How ONCO stock reacted

Close before

$1.02

Sep 4, 2026

First close after

-17.65%

$0.84

5 trading days

-37.51%

$0.64

Since filing

+604.90%

$7.19

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Frequently asked questions

What did ONCO file with the SEC on Sep 8, 2026?

ONCO filed a 424B3 (Secondary offering). Onconetix, Inc. filed a prospectus for the resale of up to 100,000,000 shares of common stock by a selling stockholder, representing 2,282% of outstanding shares as of August 28, 2026. The shares are issuable upon conversion of Series F preferred stock issued in a private placement that closed on July 29, 2026.

What does a secondary offering mean for ONCO stock?

New shares dilute existing holders and are often sold at a discount to the market price.

How do I read a 424B3?

The final terms of an offering of shares or bonds. Look at price, number of shares and the discount to the market price. Large offerings dilute existing shareholders.

Why are SEC filings important?

Public companies must tell the SEC about anything that can change their value — results, leadership changes, big deals, new shares, bankruptcy. Filings are the official source, often before the news. A 424B3 (prospectus (offering)): The final terms of an offering of shares or bonds.

How did ONCO stock react to this filing?

ONCO closed at $1.02 before the filing and $0.84 on Sep 8, 2026 (-17.65%). Five trading days later: $0.64 (-37.51%).

Other ONCO SEC filings

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