According to recent filings covering the 90 days ending December 12, 2025, the three most significant insider holders at MBX Biosciences are Director Patrick J Heron (5.22Mn shares), President & CEO P. Kent Hawryluk (1.11Mn shares), Director Steven L. Hoerter (20.00K shares).
| Holder | Position | Shares | Report Date |
|---|---|---|---|
| Patrick J Heron | 5,219,440 | 30 Sep, 2025 | |
| Life Sciences X, L.P. Frazier | 4,552,774 | 17 Sep, 2024 | |
| Scott D Sandell | 3,614,486 | 17 Sep, 2024 | |
| Anthony A. Jr. Florence | 3,614,486 | 17 Sep, 2024 | |
| Ali Behbahani | 3,614,486 | 17 Sep, 2024 | |
| Paul Edward Walker | 3,614,486 | 17 Sep, 2024 | |
| Mohamad Makhzoumi | 3,614,486 | 17 Sep, 2024 | |
| Carmen Chang | 3,614,486 | 17 Sep, 2024 | |
| Edward T Mathers | 3,614,486 | 17 Sep, 2024 | |
| Enterprise Associates 17, L.P. New | 3,614,486 | 17 Sep, 2024 | |
| Rick Yang | 3,614,486 | 17 Sep, 2024 | |
| Forest Baskett | 3,614,486 | 17 Sep, 2024 | |
| Tiba Aynechi | 2,136,335 | 17 Sep, 2024 | |
| Biomedical Innovation Master Investors (Cayman) Ii L.P. Wellington | 1,790,122 | 17 Sep, 2024 | |
| P. Kent Hawryluk | President & CEO | 1,112,533 | 28 Oct, 2025 |
| Advisors Llc Orbimed | 747,887 | 19 Feb, 2025 | |
| Carl L Gordon | 747,887 | 19 Feb, 2025 | |
| James M Cornelius | 102,082 | 17 Sep, 2024 | |
| Ora H. Pescovitz | 24,329 | 10 Apr, 2025 | |
| Steven L. Hoerter | 20,000 | 20 Oct, 2025 |
* Please note that the shares above only reflect shares from the fund portfolio and the institutional portfolio. Shares from the personal portfolio are excluded from this Institutional Ownership Page. See these insiders' latest transactions here on Insider Page.
| Transaction Date | Insider Name | Security Class | Transaction Type | Shares Traded | Price | Shares Remaining | Ownership | Code |
|---|---|---|---|---|---|---|---|---|
| 24 Oct, 2025 | P. Kent Hawryluk | Common Stock | A | 182,859 | $3.25 | 664,256 | D | M |
| 20 Oct, 2025 | P. Kent Hawryluk | Common Stock | A | 20,000 | $13.64 | 481,397 | D | P |
| 17 Oct, 2025 | Steven L. Hoerter | Common Stock | A | 20,000 | $13.25 | 20,000 | I | P |
| 26 Sep, 2025 | Patrick J Heron | - | - | 5,219,440 | I | |||
| 26 Sep, 2025 | Patrick J Heron | Common Stock | A | 666,666 | $18.00 | 5,219,440 | I | P |
| 08 Apr, 2025 | Ora H. Pescovitz | - | - | 24,329 | D | |||
| 08 Apr, 2025 | Ora H. Pescovitz | Common Stock | A | 7,693 | $5.89 | 24,329 | D | P |
| 14 Feb, 2025 | Carl L Gordon | - | - | 3,176,390 | I | |||
| 14 Feb, 2025 | Advisors Llc Orbimed | Common Stock | A | 17,962 | $9.90 | 3,176,390 | I | P |
| 14 Feb, 2025 | Carl L Gordon | Common Stock | A | 17,962 | $9.90 | 3,176,390 | I | P |
| 14 Feb, 2025 | Carl L Gordon | - | - | 3,205,930 | I | |||
| 14 Feb, 2025 | Carl L Gordon | Common Stock | A | 29,540 | $9.85 | 3,205,930 | I | P |
| 14 Feb, 2025 | Advisors Llc Orbimed | Common Stock | A | 29,540 | $9.85 | 3,205,930 | I | P |
| 18 Feb, 2025 | Carl L Gordon | Common Stock | A | 49,070 | $10.84 | 3,255,000 | I | P |
| 18 Feb, 2025 | Advisors Llc Orbimed | Common Stock | A | 49,070 | $10.84 | 3,255,000 | I | P |
| 18 Feb, 2025 | Carl L Gordon | - | - | 3,255,000 | I | |||
| 18 Feb, 2025 | Carl L Gordon | - | - | 747,887 | I | |||
| 18 Feb, 2025 | Carl L Gordon | Common Stock | A | 94,100 | $10.84 | 747,887 | I | P |
| 18 Feb, 2025 | Advisors Llc Orbimed | Common Stock | A | 94,100 | $10.84 | 747,887 | I | P |
| 04 Feb, 2025 | P. Kent Hawryluk | - | - | 448,277 | I |