FibroBiologics Inc美股招股说明书(2025-12-30版)

FibroBiologics, Inc. 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 ourcommon stock, par value $0.00001 per share, or the common stock/Common Stock, by the selling stockholders named in thisprospectus, or the Selling Stockholders. The shares of our Common Stock to which this prospectus relates consist of (i) up to12,110,203 shares of Common Stock issuable upon the exercise of common warrants issued in a private placement that closed onNovember 19, 2025, or the November 19 Warrants, (ii) up to 4,477,614 shares of Common Stock issuable upon the exercise ofcommon warrants issued in a private placement that closed on November 25, 2025, or the November 25 Warrants, (iii) up to 313,433shares 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 The shares of Common Stock being registered for resale by the Selling Stockholders in the registration statement of which thisprospectus forms a part were issued and sold pursuant to private placements, or Private Placements, which were priced at the market ata combined purchase price per share of Common Stock and accompanying Warrant of $0.3303 with respect to the November 19Warrants, $0.335 with respect to the November 25 Warrants, and $0.33 with respect to the December 16 Warrants. In addition, theCompany issued to the placement agent for the Private Placement that closed on November 25, 2025 the November 25 Placement We are not selling any securities under this prospectus and will not receive any of the proceeds from the sale of our common stock bythe Selling Stockholders. However, we may receive up to approximately $7.5 million aggregate gross proceeds upon exercise of thewarrants by the Selling Stockholders. See “Prospectus Summary—The Securities Purchase Agreements” on page 2 of this prospectus The Selling Stockholders may sell or otherwise dispose of the common stock described in this prospectus in a number of differentways and at varying prices. We will pay the expenses incurred in registering under the Securities Act the offer and sale of the shares ofthe common stock to which this prospectus relates by the Selling Stockholders, including our legal and accounting fees, but all sellingand other expenses incurred by the Selling Stockholders will be paid by them. The Securities and Exchange Commission may take aposition 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 Our common stock is listed on the Nasdaq Capital Market under the symbol “FBLG”. On December 22, 2025, the last reported salesprice 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 Investing in our common stock involves a high degree of risk. See the “Risk Factors” section beginning on page 6 of thisprospectus 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 thesesecurities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense. Prospectus Dated December 30, 2025 TABLE OF CONTENTS You should rely only on the information contained in this prospectus or contained in any free writing prospectus filed with theSecurities and Exchange Commission. Neither we nor the Selling Stockholders have authorized anyone to provide anyinformation different from, or in addition to, the information contained in this prospectus and in any free writing prospectuseswe have prepared or that have been prepared on our behalf or to which we have referred you. Neither we nor the SellingStockholders take responsibility for, and can provide no assurance as to the reliability of, any other information that othersmay give you. The Selling Stockholders are offering to sell, and seeking offers to buy, shares of our common stock only under For investors outside the United States: Neither we nor the Selling Stockholders have done anything that would permit the useof or possession or distribution of this prospectus or any related free writing prospectus in any jurisdiction where action forthat purpose is required, other than in the United States. Persons outside the United States who come into possession of this ABOUT THIS PROSPECTUS This prospectus is a