SEC Form 4 · accession 0001193125-26-331642
MBX Biosciences, Inc. · MBX
Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗
Reporting owner
John W Smither
Officer — Chief Financial Officer
Period of report
Aug 3, 2026
Accepted (ET)
Aug 4, 2026 · 8:51 am EDT
Rule 10b5-1 plan
box not checked
Issuer CIK
0001776111
Table I — non-derivative securities
| Security | Date | Code | Shares | Price | A/D | Owned after | D/I | Nature of ownership |
|---|---|---|---|---|---|---|---|---|
| Common StockF1 | Aug 3, 2026 | A | 28,000 | $0.00 | A | 28,000 | D |
Table II — derivative securities
| Security | Conv. / exercise price | Date | Code | Shares | A/D | Exercisable | Expires | Underlying | Underlying shares | Owned after | D/I |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Stock option (right to buy)F2 | $64.41 | Aug 3, 2026 | A | 130,000 | A | — | Aug 3, 2036 | Common Stock | 130,000 | 130,000 | D |
Explanation of responses
- F1Represents the grant of restricted stock units ("RSUs"). 25% of the shares subject to the RSU grant will vest annually over four years, on each July 13, 2027, 2028, 2029 and 2030, subject to continued service on each such vesting date.
- F2The options will vest and become exercisable with 25% of the shares subject to the award vesting on July 13, 2027 and the remainder vesting in 36 equal monthly installments thereafter, subject to continued service on each such vesting date.
Remarks
Exhibit 24 - Power of Attorney