MBX Biosciences, Inc. — Director's Dealing 2025

Oct 21, 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MBX Biosciences, Inc. (MBX)
CIK: 0001776111
Period of Report: 2025-10-20

Reporting Person: Hawryluk P. Kent (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2025-10-20	Common Stock	P	20000	$13.6395	Acquired	468277	Indirect

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	481397	Direct

Footnotes

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.

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.