P. Kent Hawryluk - 20 Oct 2025 Form 4 Insider Report for MBX Biosciences, Inc. (MBX)

Role: President & CEO, Director
Signature: /s/ Richard Bartram, attorney-in-fact
Issuer symbol: MBX
Transactions as of: 20 Oct 2025
Net transactions value: +$272,790
Form type: 4
Filing time: 21 Oct 2025, 17:43:44 UTC
Previous filing: 05 Feb 2025
Next filing: 28 Oct 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Hawryluk P. Kent	President & CEO, Director	C/O MBX BIOSCIENCES, INC., 11711 N. MERIDIAN STREET, SUITE 300, CARMEL	/s/ Richard Bartram, attorney-in-fact	21 Oct 2025	0001673991

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	MBX	Common Stock	Purchase	$272,790	+20,000	+4.5%	$13.64	468,277	20 Oct 2025	By Trust	F1, F2
holding	MBX	Common Stock						481,397	20 Oct 2025	Direct

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
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.

Content

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.

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.