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FibroBiologics, Inc. (FBLG) director reports option stake of 562 shares

(Neutral)
(Neutral)
Form Type
3

Rhea-AI Filing Summary

FibroBiologics, Inc. director Kathleen Hallisey Rubins reported her initial beneficial ownership of a stock option to acquire 562 shares of common stock. The option has a $65.60 exercise price, expires on 2032-09-26, and, according to a footnote, vested over three years and became fully exercisable on September 26, 2025. The option is held directly.

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Insider Rubins Kathleen Hallisey
Role Director
Type Security Shares Price Value
holding Stock Option (Right to Buy) F1 -- -- --
Holdings After Transaction: Stock Option (Right to Buy) — 562 shares (Direct)
Footnotes (1)
  1. F1. The options vested over three years and became fully exercisable on September 26, 2025.
Underlying shares 562 shares Common stock underlying the director’s stock option reported on Form 3
Exercise price $65.60 per share Exercise price of the reported stock option (Right to Buy)
Option expiration date 2032-09-26 Expiration date of the director’s stock option position
Fully exercisable date September 26, 2025 Date on which the options became fully exercisable after three-year vesting
Form 3 regulatory
"in an initial Form 3 for FibroBiologics"
Form 3 is the initial public filing that officers, directors and large shareholders must submit to report their ownership of a company’s securities when they become insiders. It acts like an opening inventory sheet that gives investors a starting point to see who holds significant stakes and to spot later trades or potential conflicts of interest, helping assess insider confidence and transparency.
Stock Option (Right to Buy financial
"security_title": "Stock Option (Right to Buy)"
exercise price financial
"has a $65.60 exercise price, expires on 2032-09-26"
The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.
underlying security financial
"underlying security title is Common Stock with 562 shares"

AI-generated analysis. How Rhea-AI works. Not financial advice.

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FAQ

What did FibroBiologics (FBLG) director Kathleen Hallisey Rubins report on this Form 3?

Kathleen Hallisey Rubins reported initial beneficial ownership of a stock option to acquire 562 shares of FibroBiologics common stock. The option is held directly and is fully vested, as described in the Form 3 disclosure and related footnote.

How many shares are covered by the stock option reported for FBLG?

The stock option reported covers 562 underlying shares of FibroBiologics common stock. This figure represents the number of common shares that may be acquired upon exercise of the option, as indicated in the Form 3 derivative holdings table.

What is the exercise price and expiration date of the FBLG director’s stock option?

The reported stock option has an exercise price of $65.60 per share and an expiration date of 2032-09-26. These terms define the cost to exercise the option and the last date on which it can be exercised.

When did the FibroBiologics (FBLG) stock options held by the director become fully exercisable?

According to the footnote, the options vested over three years and became fully exercisable on September 26, 2025. This means that from that date onward, all 562 underlying shares can be purchased under the option terms.

Is this FBLG Form 3 reporting a new transaction or existing holdings?

This Form 3 reports existing holdings of a stock option position rather than a new purchase or sale. The entry is classified as a holding, with no buy or sell transaction code disclosed in the filing data.

How is the FBLG director’s ownership of the stock option characterized?

The stock option is reported as direct ownership by the director. The filing does not attribute the holdings to any trust or entity, indicating the option is held personally rather than indirectly through another organization.
SEC Form 3
FORM 3UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number:3235-0104
Estimated average burden
hours per response:0.5
1. Name and Address of Reporting Person*
Rubins Kathleen Hallisey

(Last)(First)(Middle)
C/O FIBROBIOLOGICS, INC.
9350 KIRBY DRIVE., SUITE 300

(Street)
HOUSTON, TEXAS 77054

(City)(State)(Zip)

UNITED STATES

(Country)
2. Date of Event Requiring Statement (Month/Day/Year)
07/08/2026
3. Issuer Name and Ticker or Trading Symbol
FibroBiologics, Inc. [ FBLG ]
3a. Foreign Trading Symbol
5. If Amendment, Date of Original Filed (Month/Day/Year)
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
XDirector10% Owner
Officer (give title below)Other (specify below)
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5)
Table II - Derivative Securities Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4) 2. Date Exercisable and Expiration Date (Month/Day/Year)3. Title and Amount of Securities Underlying Derivative Security (Instr. 4) 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 6. Nature of Indirect Beneficial Ownership (Instr. 5)
Date ExercisableExpiration DateTitleAmount or Number of Shares
Stock Option (Right to Buy) (1)09/26/2032Common Stock562$65.6D
Explanation of Responses:
1. The options vested over three years and became fully exercisable on September 26, 2025.
Remarks:
Exhibit 24 Power of Attorney
/s/ Ruben A. Garcia, by Power of Attorney07/16/2026
** Signature of Reporting PersonDate
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 3: SEC 1473 (03-26)