The terms, per the Form 424B3 Onconetix, Inc. (Nasdaq: ONCO) filed on June 17, 2026: the company is registering up to 100,000,000 shares of common stock for resale by Keystone Capital Partners, LLC, the shares it has issued or may issue to Keystone under a Common Stock ELOC Purchase Agreement dated October 2, 2024. The headline capacity of that equity line of credit is up to $25 million in aggregate gross proceeds. Strip the spin and this is not a fundraise in the conventional sense - it is a registration that keeps an at-the-market drip facility alive for a commercial-stage oncology diagnostics micro-cap that, by its own account, does not have a year of runway in the bank.
Two numbers frame the stakes. Onconetix reported cash of approximately $3.7 million as of March 31, 2026 and, after subsequent draws, approximately $6.5 million as of June 5, 2026, against an accumulated deficit of approximately $135.4 million. During the quarter ended March 31, 2026 it burned roughly $2.1 million in operating cash. The prospectus is candid about what that combination means.
"There is substantial doubt about our ability to continue as a “going concern,” and we will require substantial additional funding to finance our long-term operations. If we are unable to raise additional capital when needed, we could be forced to delay, reduce or terminate our product or other operations."— Onconetix, Inc. Form 424B3, source
How the Keystone equity line actually works
Disclosed, not promised: the mechanics of this facility matter more than the $25 million ceiling. Onconetix is not selling securities directly under this prospectus and, in its own words, "will not receive any proceeds from the sale of Common Stock by the Selling Stockholder." Keystone is the registered seller. The company only puts cash in the door when it elects, at its sole discretion, to sell newly issued shares to Keystone, who is named in the filing as an "underwriter" within the meaning of Section 2(a)(11) of the Securities Act and who then resells into the public market. The purchase price Keystone pays floats with the prevailing market price at the time of each draw - the prospectus uses an assumed price of $0.1375 per share to arrive at the 100,000,000-share registration figure, but the actual share count issued will vary with where ONCO trades.
That floating, market-linked pricing is the defining feature of an ELOC, and it is also where the dilution math gets uncomfortable. The company has already leaned on this line: through June 5, 2026 it had sold approximately 2.6 million split-adjusted shares to Keystone for aggregate proceeds of approximately $11.3 million. The prospectus warns plainly that as it continues to draw, "substantial amounts of shares could be issued and resold, which would cause dilution and may impact the Company's stock price." For existing holders, an equity line is a slow leak rather than a single dilutive event - it converts the share count into a function of the cash burn.
A reverse split, a warrant reset, and a thin cash cushion
The capital structure has been actively reshaped in the run-up to this filing. On May 21, 2026 Onconetix effected a one-for-ten reverse stock split, accounted for retrospectively, adjusting all outstanding common stock, warrants, and share-based awards. Reverse splits at this end of the market are typically about staying compliant with Nasdaq's minimum bid-price rule rather than about value creation, and the last reported sale price cited in the prospectus was $1.08 on June 16, 2026 - a level that leaves little margin above a $1.00 listing threshold once the share count starts climbing again under the equity line.
The overhang does not stop at the ELOC. The filing describes Series E Warrants with an anti-dilution structure: originally exercisable for 2,025,223 shares at $3.8576, adjusted post-split to 1,070,498 shares, with an exercise-price reset mechanism tied to the lowest volume-weighted average price over a defined window - a reset the company expected to trigger on June 12, 2026. Resetting strikes lower as the stock falls is a classic ratchet that compounds dilution precisely when a company can least afford it. Onconetix also points to Series D and Series E PIPE financings closed in September and October 2025 as recent sources of near-term cash, and notes that other than the committed equity facility itself, "there are currently no committed sources of financing."
What the company is actually trying to fund
Onconetix's commercial bet is Proclarix, a protein-based blood test for prostate cancer acquired through its 2023 purchase of Proteomedix. Proclarix is CE-marked and sold in Europe under the In Vitro Diagnostic Regulation, and the company intends to market it in the U.S. as a laboratory-developed test through a license arrangement with Labcorp, supported by the PRIME validation study designed to enroll up to 500 men. The company has already abandoned commercialization of ENTADFI, its FDA-approved BPH pill, and fully impaired those assets - a reminder that this is a business that has had to shed programs to conserve cash.
The runway arithmetic is the whole story. At roughly $2.1 million of quarterly operating cash burn and approximately $6.5 million on hand at the start of June, the existing balance covers a handful of quarters before the equity line has to do real work. The going-concern language is not boilerplate here; management explicitly states that current cash "is not sufficient to fund its operations for one year from the date of issuance" of the financial statements, and that the substantial-doubt conclusion attaches to both the fiscal year ended December 31, 2025 and the period ended March 31, 2026.
For investors, the takeaway is structural rather than directional. An equity line is a financing of last resort dressed as flexibility: it keeps a small-cap solvent quarter to quarter, but it does so by selling shares into weakness at the company's discretion, with every draw enlarging the float and pressuring the price that determines the next draw. The $25 million ceiling and 100-million-share registration set the outer bounds of how far that dilution can run before another registration statement is required. Whether Proclarix's U.S. commercialization can outrun the burn before the equity line exhausts itself - or before the next reverse split - is the question this prospectus leaves open, and answers only with a warning.