FibroBiologics, Inc.

S-11 forms-1.htm S-1

As filed with the Securities and Exchange Commission on December 23, 2025.

Registration No.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

(Exact name of registrant as specified in its charter)

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

Pete O’Heeron

Chief Executive Officer

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

Copies to:

Ruben A. Garcia

General Counsel

Approximate date of commencement of proposed sale to the public:As soon as practicable after this registration statement becomes effective.

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, please 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, 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, as amended, or until the registration statement shall become effective on such date as the Securities and Exchange Commission acting pursuant to said Section 8(a), may determine.

The information in this preliminary prospectus is not complete and may be changed. These securities may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary 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.

Up to 22,494,434 Shares of Common Stock

This prospectus relates to the registration of the resale or other disposition, from time to time, of up to 22,494,434 shares of our common stock, par value $0.00001 per share, or the common stock/Common Stock, by the selling stockholders named in this prospectus, or the Selling Stockholders. The shares of our Common Stock to which this prospectus relates consist of (i) up to 12,110,203 shares of Common Stock issuable upon the exercise of common warrants issued in a private placement that closed on November 19, 2025, or the November 19 Warrants, (ii) up to 4,477,614 shares of Common Stock issuable upon the exercise of common warrants issued in a private placement that closed on November 25, 2025, or the November 25 Warrants, (iii) up to 313,433 shares of Common Stock issuable upon the exercise of placement agent warrants issued concurrently with the November 25 Warrants, or the November 25 Placement Agent Warrants, (iv) up to 5,227,275 shares of Common Stock issuable upon the exercise of common warrants issued in a private placement that closed on December 16, 2025, or the December 16 Warrants, and (v) up to 365,909 shares of Common Stock issuable upon the exercise of placement agent warrants issued concurrently with the December 16 Warrants, or the December 16 Placement Agent Warrants and, together with the November 19 Warrants, the November 25 Warrants, the November 25 Placement Agent Warrants, and the December 16 Warrants, the Warrants.

The shares of Common Stock being registered for resale by the Selling Stockholders in the registration statement of which this prospectus forms a part were issued and sold pursuant to private placements, or Private Placements, which were priced at the market at a combined purchase price per share of Common Stock and accompanying Warrant of $0.3303 with respect to the November 19 Warrants, $0.335 with respect to the November 25 Warrants, and $0.33 with respect to the December 16 Warrants. In addition, the Company issued to the placement agent for the Private Placement that closed on November 25, 2025 the November 25 Placement Agent Warrants to purchase up to an aggregate of 313,433 shares of Common Stock, at an exercise price equal to $0.4188 per share, and for the Private Placement that closed on December 16, 2025 the December 16 Placement Agent Warrants to purchase up to an aggregate of 365,909 shares of Common Stock, at an exercise price equal to $0.4125 per share. The Warrants will be exercisable upon receipt of the Stockholder Approvals (as defined below).

We are not selling any securities under this prospectus and will not receive any of the proceeds from the sale of our common stock by the Selling Stockholders. However, we may receive up to approximately $7.5 million aggregate gross proceeds upon exercise of the warrants by the Selling Stockholders. See “Prospectus Summary—The Securities Purchase Agreements” on page 2 of this prospectus for a description of the securities purchase agreements and Warrants and “Principal and Selling Stockholders” on page 10 of this prospectus for additional information regarding the Selling Stockholders.

The Selling Stockholders may sell or otherwise dispose of the common stock described in this prospectus in a number of different ways and at varying prices. We will pay the expenses incurred in registering under the Securities Act the offer and sale of the shares of the common stock to which this prospectus relates by the Selling Stockholders, including our legal and accounting fees, but all selling and other expenses incurred by the Selling Stockholders will be paid by them. The Securities and Exchange Commission may take a position that each of the Selling Stockholders is an “underwriter” within the meaning of Section 2(a)(11) of the Securities Act of 1933, as amended, or the Securities Act. See the sections “About this Prospectus” on page 1 and “Plan of Distribution” on page 15 of this prospectus for more information. No securities may be sold without delivery of this prospectus and any applicable prospectus supplement describing the method and terms of the offering of such securities. You should carefully read this prospectus and any applicable prospectus supplement before you invest in our securities.

Our common stock is listed on the Nasdaq Capital Market under the symbol “FBLG”. On December 22, 2025, the last reported sales price of our common stock was $0.2596 per share.

We are an “emerging growth company” and a “smaller reporting company” as defined under the federal securities laws and, as such, have elected to comply with certain reduced public company reporting requirements for this prospectus and may elect to do so in future filings. See “Prospectus Summary—Implications of Being an Emerging Growth Company and a Smaller Reporting Company.”

Investing in our common stock involves a high degree of risk. See the “Risk Factors” section beginning on page 6 of this prospectus for the risks and uncertainties you should consider before investing in our common stock.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Prospectus Dated , 2025

TABLE OF CONTENTS

You should rely only on the information contained in this prospectus or contained in any free writing prospectus filed with the Securities and Exchange Commission. Neither we nor the Selling Stockholders have authorized anyone to provide any information different from, or in addition to, the information contained in this prospectus and in any free writing prospectuses we have prepared or that have been prepared on our behalf or to which we have referred you. Neither we nor the Selling Stockholders take responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. The Selling Stockholders are offering to sell, and seeking offers to buy, shares of our common stock only under the circumstances and in jurisdictions where it is lawful to do so. The information contained in this prospectus is current only as of its date, regardless of the time of delivery of this prospectus or of any sale of our common stock. Our business, financial condition, results of operations and prospects may have changed since such date.

For investors outside the United States: Neither we nor the Selling Stockholders have done anything that would permit the use of or possession or distribution of this prospectus or any related free writing prospectus in any jurisdiction where action for that purpose is required, other than in the United States. Persons outside the United States who come into possession of this prospectus must inform themselves about, and observe any restrictions relating to, the offering of the shares of our common stock by the Selling Stockholders and the distribution of this prospectus outside the United States.