MBX director Stelzer files Form 3 with no holdings

MBX Biosciences director files initial ownership report with no holdings MBX Biosciences, Inc. director Laurie Stelzer filed an initial Form 3 ownership report related to an event dated 01/20/2026.

Accepted by SEC EDGAR 01/22/2026 - 08:06 AM EST Learn about SEC filing dates

Rhea-AI Filing Summary

MBX Biosciences director files initial ownership report with no holdings

MBX Biosciences, Inc. director Laurie Stelzer filed an initial Form 3 ownership report related to an event dated 01/20/2026. The filing identifies Stelzer as a director of MBX Biosciences and indicates that no non-derivative or derivative securities of the company are beneficially owned. The remarks section explicitly states that no securities are beneficially owned, confirming there are currently no reported MBX Biosciences shares or derivative instruments held by this reporting person.

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SEC Form 3

FORM 3

UNITED 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^*

Stelzer Laurie

(Last) (First) (Middle)

C/O MBX BIOSCIENCES, INC.

11711 N. MERIDIAN STREET, STE 300

(Street)

CARMEL IN 46032

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
01/20/2026

3. Issuer Name and Ticker or Trading Symbol
MBX Biosciences, Inc. [ MBX ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

5. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form 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 Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

Remarks:

Exhibit 24 - Power of Attorney

No securities are beneficially owned.

	/s/ Richard Bartram, attorney-in-fact	01/22/2026
	** Signature of Reporting Person	Date
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.