Laurie Stelzer - 04 Jun 2026 Form 4 Insider Report for MBX Biosciences, Inc. (MBX)

Reporting relationship: Director
Issuer ticker: MBX
Reported as of: 04 Jun 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 05 Jun 2026, 07:58:21 UTC
Prior SEC filing: 29 May 2026
Next SEC filing: 18 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ P. Kent Hawryluk, attorney-in-fact

Key filing fact

Laurie Stelzer filed Form 4 for MBX Biosciences, Inc. (MBX) on 05 Jun 2026.

Key facts

This page summarizes Laurie Stelzer's Form 4 filing for MBX Biosciences, Inc. (MBX).
1 reported transaction and 1 derivative row are listed below.
Accepted by SEC: 05 Jun 2026, 07:58.

Change

Previous filing in this sequence was filed on 29 May 2026.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001644348 Primary reporting owner

Stelzer Laurie

Relationship: Director
Address: C/O MBX BIOSCIENCES, INC., 11711 N. MERIDIAN STREET, STE 300, CARMEL
Signature: /s/ P. Kent Hawryluk, attorney-in-fact
Signature date: 05 Jun 2026

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

MBX transaction Derivative

Stock option (right to buy)

Award

Transaction value
Shares: +12,500
Change %
Price: $0.000000^*
Shares after: 12,500
Date: 04 Jun 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 12,500
Exercise price: $30.91
Footnotes: F1

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 1 footnote

Footnote F1

The grant will vest in full on the earlier of the one-year anniversary of the grant date or on the date of our next annual meeting of stockholders, subject to the non-employee director's continued services to the Company.