<SEC-DOCUMENT>0001493152-26-008646.txt : 20260303
<SEC-HEADER>0001493152-26-008646.hdr.sgml : 20260303
<ACCEPTANCE-DATETIME>20260303080020
ACCESSION NUMBER:		0001493152-26-008646
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20260302
FILED AS OF DATE:		20260303
DATE AS OF CHANGE:		20260303

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Davis Jason
		CENTRAL INDEX KEY:			0001443533
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-41934
		FILM NUMBER:		26711092

	MAIL ADDRESS:	
		STREET 1:		27003 BARRINGTON LODGE LN
		CITY:			KATY
		STATE:			TX
		ZIP:			77494

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FibroBiologics, Inc.
		CENTRAL INDEX KEY:			0001958777
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				863329066
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		455 E. MEDICAL CENTER BLVD
		STREET 2:		SUITE 300
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77598
		BUSINESS PHONE:		281-671-5150

	MAIL ADDRESS:	
		STREET 1:		455 E. MEDICAL CENTER BLVD SUITE 300
		STREET 2:		SUITE 300
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77598

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FibroBiologics Inc.
		DATE OF NAME CHANGE:	20221216
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>ownership.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-03-02</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001958777</issuerCik>
        <issuerName>FibroBiologics, Inc.</issuerName>
        <issuerTradingSymbol>FBLG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001443533</rptOwnerCik>
            <rptOwnerName>Davis Jason</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O FIBROBIOLOGICS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>455 E. MEDICAL CENTER BLVD., SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>HOUSTON,</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77598</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Financial Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-03-02</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>70000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.4139</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>70000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $0.3968 to $0.4200 on March 2, 2026. The reporting person will provide upon request to the SEC, the Issuer, or security holder of the Issuer, full information regarding the number of shares purchased at each separate price.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Ruben A. Garcia, by Power of Attorney</signatureName>
        <signatureDate>2026-03-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
