Decoy Therapeutics Inc.

S-11 dcoy-20261007.htm S-1

As filed with the Securities and Exchange Commission on October 7, 2026

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

DECOY THERAPEUTICS INC.

(Exact name of registrant as specified in its charter)

2450 Holcombe Blvd., Suite X

Houston, TX 77021

(713) 913-5608

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Frederick E. Pierce

Chief Executive Officer

Decoy Therapeutics Inc.

2450 Holcombe Blvd., Suite X

Houston, TX 77021

(713) 913-5608

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Jeffrey H. Kuras, Esq.

Honigman LLP

660 Woodward Avenue, 2290 First National Building

Detroit, MI 48226

(313) 465-7000

Approximate date of commencement of proposed sale to the public: From time to time after the effective date of this registration statement, as determined by the selling stockholder.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box. ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

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 7(a)(2)(B) of the Securities Act. ☐

The Registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the registration statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. The selling stockholder may not sell these securities until the registration statement filed with the U.S. Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED OCTOBER 7, 2026

PRELIMINARY PROSPECTUS

DECOY THERAPEUTICS INC.

Up to 2,368,868 Shares of Common Stock

This prospectus relates to the resale from time to time by the selling stockholder identified in this prospectus (the “selling stockholder”) of up to 2,368,868 shares of our common stock, par value $0.0001 per share (“common stock”) issuable upon the exercise of common stock purchase warrants (the “New Warrants”). We issued the New Warrants to a certain investor as consideration for such investor’s exercise of Series B milestone-based common stock purchase warrants (the “Existing Series B Warrants”) issued on June 29, 2026, pursuant to the terms of a warrant inducement offer letter (the “Inducement Letter”) with the investor to immediately exercise its Existing Series B Warrants. The New Warrants were issued in a private placement that closed on September 23, 2026, as described under “The Private Placement.”

We are not selling any securities under this prospectus and will not receive any of the proceeds from the resale of shares of common stock by the selling stockholder. We will, however, receive the proceeds of any cash exercise of the New Warrants. See “Use of Proceeds.”

The selling stockholder may sell or otherwise dispose of the shares of common stock described in this prospectus in a number of different ways and at varying prices. See “Plan of Distribution.” We have agreed to pay certain expenses in connection with the registration of the shares of common stock and to indemnify the selling stockholder against certain liabilities. See “Plan of Distribution.”

We are filing the registration statement on Form S-1 of which this prospectus forms a part to fulfill our contractual obligations to the selling stockholder to provide for the resale by the selling stockholder of the shares of common stock issuable upon exercise of the New Warrants. See “Selling Stockholder” beginning on page 17 of this prospectus for more information about the selling stockholder. Our registration of the securities covered by this prospectus does not mean that either we or the selling stockholder will issue, offer or sell any of the shares of common stock.

Our common stock is listed on The Nasdaq Capital Market (“Nasdaq”) under the symbol “DCOY.” On October 6, 2026, the last reported sale price of our common stock was $1.55 per share. As of such date, we had 2,385,282 shares of common stock outstanding.

Our cash, cash equivalents and restricted cash balance as of September 30, 2026 was approximately $8.0 million, of which $2.5 million is restricted for use under our Gates Foundation Grant Agreement and can only be used for specific development purpose.

We are a “smaller reporting company” under the federal securities laws and have elected to comply with certain reduced public company reporting requirements. See “Prospectus Summary — Implications of Being a Smaller Reporting Company.”

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading “Risk Factors” beginning on page 10 of this prospectus, and under similar headings in any amendment of or supplement to this prospectus or in any other documents that are incorporated by reference into this prospectus.

NEITHER THE SEC NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR PASSED UPON THE ADEQUACY OR ACCURACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

The date of this prospectus is , 2026.