<SEC-DOCUMENT>0001193125-25-245411.txt : 20251021
<SEC-HEADER>0001193125-25-245411.hdr.sgml : 20251021
<ACCEPTANCE-DATETIME>20251021174344
ACCESSION NUMBER:		0001193125-25-245411
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20251020
FILED AS OF DATE:		20251021
DATE AS OF CHANGE:		20251021

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Hawryluk P. Kent
		CENTRAL INDEX KEY:			0001673991
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-42272
		FILM NUMBER:		251408146

	MAIL ADDRESS:	
		STREET 1:		17199 N. LAUREL PARK DRIVE
		STREET 2:		SUITE 401
		CITY:			LIVONIA
		STATE:			MI
		ZIP:			48152

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MBX Biosciences, Inc.
		CENTRAL INDEX KEY:			0001776111
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		11711 N. MERIDIAN STREET
		STREET 2:		SUITE 300
		CITY:			CARMEL
		STATE:			IN
		ZIP:			46032
		BUSINESS PHONE:		3179893100

	MAIL ADDRESS:	
		STREET 1:		11711 N. MERIDIAN STREET
		STREET 2:		SUITE 300
		CITY:			CARMEL
		STATE:			IN
		ZIP:			46032
</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>2025-10-20</periodOfReport>

    <issuer>
        <issuerCik>0001776111</issuerCik>
        <issuerName>MBX Biosciences, Inc.</issuerName>
        <issuerTradingSymbol>MBX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001673991</rptOwnerCik>
            <rptOwnerName>Hawryluk P. Kent</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MBX BIOSCIENCES, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>11711 N. MERIDIAN STREET, SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>CARMEL</rptOwnerCity>
            <rptOwnerState>IN</rptOwnerState>
            <rptOwnerZipCode>46032</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>President &amp; CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>false</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>481397</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-10-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>13.6395</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>468277</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </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 at prices ranging from $13.60 to $13.6399, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote.</footnote>
        <footnote id="F2">Shares held by the P. Kent Hawryluk Revocable Trust dated January 25, 2011, of which the Reporting Person serves as trustee. The Reporting Person disclaims beneficial ownership except to the extent of any pecuniary interest therein, and this report shall not be deemed an admission that such shares are beneficially owned by him for Section 16 or any other purpose.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Richard Bartram, attorney-in-fact</signatureName>
        <signatureDate>2025-10-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
