Corporate Action, Amendments to Bylaws (Form 8-K)

Item 3.03 Material Modification to Rights of Security Holders.

To the extent required by Item 3.03 of Form 8-K, the information regarding the Reverse Stock Split (as defined below) contained in Item 5.03 of this Current Report on Form 8-K is incorporated by reference herein.

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

On March 25, 2026, FibroBiologics, Inc. (the "Company") filed a Certificate of Amendment to the Company's Amended and Restated Certificate of Incorporation, as amended, with the Secretary of State of the State of Delaware (the "Certificate of Amendment"), which became effective at 12:01 a.m. Eastern Time on March 30, 2026, and implemented a one-for-twenty (1:20) reverse stock split (the "Reverse Stock Split") of the Company's issued and outstanding shares of common stock, par value $0.00001 per share (the "Common Stock"). In connection with the Reverse Stock Split, the CUSIP number for the Common Stock changed to 31573L204. The trading symbol for the Common Stock remains "FBLG".

As a result of the Reverse Stock Split, every twenty (20) shares of Common Stock issued and outstanding were converted into one (1) share of Common Stock. No fractional shares will be issued in connection with the Reverse Stock Split. Any fractional shares of Common Stock resulting from the Reverse Stock Split will be rounded up to the nearest whole share. The Reverse Stock Split affects all stockholders uniformly and does not alter any stockholder's percentage ownership interest in the Company, except for adjustments related to fractional shares. The Reverse Stock Split will also proportionately adjust the number of shares available under the Company's equity incentive plan and the exercise price and number of shares underlying stock options and warrants outstanding on the day the Reverse Stock Split was effective, in each case in accordance with their terms. The Reverse Stock Split did not change the par value of the Common Stock or the authorized number of shares of Common Stock

The foregoing description of the Certificate of Amendment is a summary of the material terms thereof, does not purport to be complete and is qualified in its entirety by reference to the full text of the Certificate of Amendment, which is filed with this Current Report on Form 8-K as Exhibit 3.1 and is incorporated herein by reference.