MBX Biosciences (MBX) CMO awarded 15,000 RSUs and 70,000 options

Rhea-AI Filing Summary

MBX Biosciences Chief Medical Officer Azoulay Salomon reported new equity compensation. On February 2, 2026, Salomon received 15,000 shares of common stock, representing a grant of restricted stock units that vest over four years in equal quarterly installments, conditioned on continued service.

On the same date, Salomon was also granted a stock option for 70,000 shares of common stock with an exercise price of $39.07 per share. These options vest and become exercisable in 48 equal monthly installments beginning on March 2, 2026, also subject to continued service. Following these grants, Salomon beneficially owns 15,000 common shares and 70,000 derivative securities directly.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Azoulay Salomon

Role Chief Medical Officer

Type	Security	Shares	Price	Value
Grant/Award	Stock option (right to buy)	70,000	$0.00	--
Grant/Award	Common Stock	15,000	$0.00	--

Holdings After Transaction: Stock option (right to buy) — 70,000 shares (Direct); Common Stock — 15,000 shares (Direct)

Footnotes (1)

1. Represents the grant of restricted stock units (RSUs). The RSUs will vest over a four (4) year period in equal quarterly installments, subject to the Reporting Person's continued service on such vesting date. The shares underlying this option vest and become exercisable in forty eight (48) equal monthly installments, beginning on March 2, 2026, subject to the Reporting Person's continued service on such vesting date.

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Azoulay Salomon

(Last) (First) (Middle)

C/O MBX BIOSCIENCES, INC.

11711 N. MERIDIAN STREET, SUITE 300

(Street)

CARMEL IN 46032

(City) (State) (Zip)

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

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

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

3. Date of Earliest Transaction (Month/Day/Year)
02/02/2026

4. 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 Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	02/02/2026		A		15,000(1)	A	$0	15,000	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock option (right to buy)	$39.07	02/02/2026		A		70,000		(2)	02/02/2036	Common Stock	70,000	$0	70,000	D

Explanation of Responses:

1. Represents the grant of restricted stock units (RSUs). The RSUs will vest over a four (4) year period in equal quarterly installments, subject to the Reporting Person's continued service on such vesting date.

2. The shares underlying this option vest and become exercisable in forty eight (48) equal monthly installments, beginning on March 2, 2026, subject to the Reporting Person's continued service on such vesting date.

	/s/ Richard Bartram, attorney-in-fact	02/03/2026
	** 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 4 (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.

FAQ

What insider transaction did MBX (MBX) report for Azoulay Salomon?

MBX reported that Chief Medical Officer Azoulay Salomon received equity grants on February 2, 2026. These included 15,000 restricted stock units and a stock option for 70,000 shares, both subject to multi-year vesting and continued service conditions.

How many MBX (MBX) restricted stock units were granted to the CMO?

Azoulay Salomon was granted 15,000 MBX restricted stock units. These RSUs vest over four years in equal quarterly installments, provided Salomon continues to serve the company on each vesting date, aligning compensation with ongoing employment.

What stock options did MBX (MBX) grant to its Chief Medical Officer?

MBX granted Azoulay Salomon a stock option covering 70,000 shares of common stock. The option has an exercise price of $39.07 per share and vests in 48 equal monthly installments, beginning March 2, 2026, contingent on continued service.

What is the vesting schedule for MBX (MBX) RSUs granted to Azoulay Salomon?

The 15,000 MBX RSUs granted to Azoulay Salomon vest over four years in equal quarterly installments. Each installment requires Salomon’s continued service with the company on the applicable vesting date for the shares to be earned.

When do the MBX (MBX) stock options for Azoulay Salomon start vesting?

The MBX stock options granted to Azoulay Salomon start vesting on March 2, 2026. Vesting occurs in 48 equal monthly installments, and each monthly tranche requires continued service on the applicable vesting date to become exercisable.

How many MBX (MBX) shares does Azoulay Salomon beneficially own after these grants?

After the reported grants, Azoulay Salomon beneficially owns 15,000 shares of MBX common stock and 70,000 derivative securities in the form of stock options. All are reported as directly owned positions in the Form 4 filing.