MBX Biosciences director receives stock option grant

MBX Biosciences, Inc. reported that director Steven L. Hoerter received a grant of stock options covering 33,751 shares of common stock.

Rhea-AI Filing Summary

MBX Biosciences, Inc. reported that director Steven L. Hoerter received a grant of stock options covering 33,751 shares of common stock. The options have an exercise price of $24.74 per share and were awarded as part of the company’s Non-Employee Director Compensation Policy.

The footnotes state that these grants were adjusted so the director’s total 2025 equity compensation does not exceed $1,000,000 based on grant date fair value under FASB Topic ASC 718. The grant vests in equal monthly installments over one year, contingent on his continued service to the company.

Insider Trade Summary

Grant/Award: 33,751 shares

Grant/Award 1 txn

Insider Hoerter Steven L.

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Stock option (right to buy)	33,751	$0.00	$0.00

Holdings After Transaction: Stock option (right to buy) — 33,751 contracts (Direct)

Footnotes (2)

1. F1. Pursuant to the Company's Non-Employee Director Compensation Policy, these grants were adjusted downward such that the non-employee Director's annual equity compensation in 2025 totals no more than $1,000,000 based on the aggregate grant date fair value as determined in accordance with FASB Topic ASC 718.
2. F2. The grant will vest in equal monthly installments over a one-year period from the date of grant, subject to the non-employee director's continued services to the Company.

Key Figures

Option grant size: 33,751 shares Exercise price: $24.74 per share Total options after grant: 33,751 options +3 more

6 metrics

Option grant size 33,751 shares Stock option grant to Steven L. Hoerter

Exercise price $24.74 per share Stock option exercise price

Total options after grant 33,751 options Total derivative securities following transaction

Equity compensation cap $1,000,000 2025 annual equity compensation limit under policy

Option expiration date November 5, 2035 Stock option term end date

Vesting period 1 year, monthly installments Options vest monthly over one year

Key Terms

Non-Employee Director Compensation Policy, grant date fair value, FASB Topic ASC 718, vest in equal monthly installments

4 terms

Non-Employee Director Compensation Policy financial

"Pursuant to the Company's Non-Employee Director Compensation Policy, these grants were adjusted downward..."

grant date fair value financial

"annual equity compensation in 2025 totals no more than $1,000,000 based on the aggregate grant date fair value..."

The grant date fair value is the estimated dollar worth of a stock-based award (such as stock options or restricted shares) at the exact moment it is given to an employee or contractor. Investors care because companies use that value to record compensation expenses and to show how much potential ownership and earnings dilution those awards could create—think of it as the price tag placed on a gift card when it is handed over so the company can report the cost now.

FASB Topic ASC 718 financial

"grant date fair value as determined in accordance with FASB Topic ASC 718."

vest in equal monthly installments financial

"The grant will vest in equal monthly installments over a one-year period from the date of grant..."

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did MBX (MBX) report for Steven L. Hoerter?

MBX Biosciences reported that director Steven L. Hoerter received a grant of stock options for 33,751 shares. These options allow him to buy MBX common stock at $24.74 per share and represent equity-based compensation rather than an open-market stock purchase or sale.

Is the MBX (MBX) option grant to Steven Hoerter a buy or a sale?

The filing shows an acquisition of derivative securities through a stock option grant, not a market buy or sale. Code "A" indicates a grant or award, providing rights to purchase shares at $24.74, subject to vesting, instead of immediate trading in the company’s stock.

How many MBX (MBX) shares are covered by Steven Hoerter’s option grant?

The option grant covers 33,751 shares of MBX common stock. Following the transaction, his total options from this grant are 33,751, giving him the right to purchase that number of shares at the fixed exercise price if vesting and other conditions are satisfied.

What is the exercise price and term of the MBX (MBX) stock options granted?

The options granted to Steven Hoerter have an exercise price of $24.74 per share and an expiration date of November 5, 2035. This means he can choose to exercise vested options at that price any time before they expire, subject to plan rules.

How do the MBX (MBX) director option grants relate to the $1,000,000 cap?

Footnotes state the grants were adjusted so the non-employee director’s total 2025 equity compensation does not exceed $1,000,000. This cap is measured using the aggregate grant date fair value of the awards, determined under accounting standard FASB Topic ASC 718.

What is the vesting schedule for the MBX (MBX) options granted to Steven Hoerter?

The options vest in equal monthly installments over one year from the grant date. Vesting is conditioned on Steven Hoerter’s continued service as a non-employee director, so he earns the right to exercise portions of the grant gradually throughout the year.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 04/22/2026 - 08:01 AM Learn about SEC filing dates

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^*

Hoerter Steven L.

(Last) (First) (Middle)

C/O MBX BIOSCIENCES INC.

11711 N. MERIDIAN STREET, SUITE 300

(Street)

CARMEL INDIANA 46032

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
11/06/2025

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

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)
11/07/2025

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

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)	$24.74	11/06/2025		A		33,751(1)		(2)	11/05/2035	Common Stock	33,751	$0	33,751	D

Explanation of Responses:

1. Pursuant to the Company's Non-Employee Director Compensation Policy, these grants were adjusted downward such that the non-employee Director's annual equity compensation in 2025 totals no more than $1,000,000 based on the aggregate grant date fair value as determined in accordance with FASB Topic ASC 718.

2. The grant will vest in equal monthly installments over a one-year period from the date of grant, subject to the non-employee director's continued services to the Company.

	/s/ P. Kent Hawryluk, attorney-in-fact	04/22/2026
	** 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 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.
* Form 4: SEC 1474 (03-26)