As of March 23, 2026, MBX Biosciences's top three insider holders are Patrick J Heron (Director, 5.22Mn shares), Life Sciences X, L.P. Frazier (TenPercentOwner, 4.55Mn shares), Carmen Chang (TenPercentOwner, 3.61Mn shares).
| Holder | Position | Shares (Direct) | Shares (Indirect) | Report Date |
|---|---|---|---|---|
| Patrick J Heron | 0 | 5,219,440 | 30 Sep, 2025 | |
| Life Sciences X, L.P. Frazier | 4,552,774 | 0 | 17 Sep, 2024 | |
| Carmen Chang | 0 | 3,614,486 | 17 Sep, 2024 | |
| Enterprise Associates 17, L.P. New | 3,614,486 | 0 | 17 Sep, 2024 | |
| Mohamad Makhzoumi | 0 | 3,614,486 | 17 Sep, 2024 | |
| Paul Edward Walker | 0 | 3,614,486 | 17 Sep, 2024 | |
| Edward T Mathers | 0 | 3,614,486 | 17 Sep, 2024 | |
| Anthony A. Jr. Florence | 0 | 3,614,486 | 17 Sep, 2024 | |
| Ali Behbahani | 0 | 3,614,486 | 17 Sep, 2024 | |
| Rick Yang | 0 | 3,614,486 | 17 Sep, 2024 | |
| Forest Baskett | 0 | 3,614,486 | 17 Sep, 2024 | |
| Anthony A. Jr. Florence | 0 | 3,614,486 | 17 Sep, 2024 | |
| Ali Behbahani | 0 | 3,614,486 | 17 Sep, 2024 | |
| Carmen Chang | 0 | 3,614,486 | 17 Sep, 2024 | |
| Scott D Sandell | 0 | 3,614,486 | 17 Sep, 2024 | |
| Tiba Aynechi | 0 | 2,136,335 | 17 Sep, 2024 | |
| Biomedical Innovation Master Investors (Cayman) Ii L.P. Wellington | 1,790,122 | 0 | 17 Sep, 2024 | |
| Advisors Llc Orbimed | 0 | 747,887 | 19 Feb, 2025 | |
| P. Kent Hawryluk | President Ceo | 728,274 | 0 | 27 Feb, 2026 |
| P. Kent Hawryluk | President Ceo | 728,274 | 0 | 27 Feb, 2026 |
| P. Kent Hawryluk | President Ceo | 0 | 486,777 | 16 Mar, 2026 |
| P. Kent Hawryluk | President Ceo | 0 | 468,277 | 21 Oct, 2025 |
| Ora H. Pescovitz | 24,329 | 0 | 10 Apr, 2025 | |
| Salomon Azoulay | Chief Medical Officer | 15,000 | 0 | 03 Feb, 2026 |
| Richard Bartram | Chief Financial Officer | 15,000 | 0 | 03 Feb, 2026 |
* 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 |
|---|---|---|---|---|---|---|---|---|
| 13 Mar, 2026 | P. Kent Hawryluk | Common Stock | A | 18,500 | $28.41 | 486,777 | I | P |
| 26 Feb, 2026 | P. Kent Hawryluk | Common Stock | A | 28,768 | $16.00 | 728,274 | D | M |
| 26 Feb, 2026 | P. Kent Hawryluk | Common Stock | A | 28,768 | $16.00 | 728,274 | D | M |
| 26 Feb, 2026 | P. Kent Hawryluk | Stock option (right to buy) | D | 28,768 | $0.00 | 91,668 | D | M |
| 26 Feb, 2026 | P. Kent Hawryluk | Stock option (right to buy) | D | 28,768 | $0.00 | 91,668 | D | M |
| 02 Feb, 2026 | Richard Bartram | Common Stock | A | 15,000 | $0.00 | 15,000 | D | A |
| 02 Feb, 2026 | P. Kent Hawryluk | Common Stock | A | 35,250 | $0.00 | 699,506 | D | A |
| 02 Feb, 2026 | Salomon Azoulay | Common Stock | A | 15,000 | $0.00 | 15,000 | D | A |
| 02 Feb, 2026 | P. Kent Hawryluk | Common Stock | A | 35,250 | $0.00 | 699,506 | D | A |
| 02 Feb, 2026 | Richard Bartram | Stock option (right to buy) | A | 70,000 | $0.00 | 70,000 | D | A |
| 02 Feb, 2026 | Salomon Azoulay | Stock option (right to buy) | A | 70,000 | $0.00 | 70,000 | D | A |
| 02 Feb, 2026 | P. Kent Hawryluk | Stock option (right to buy) | A | 164,500 | $0.00 | 164,500 | D | A |
| 02 Feb, 2026 | P. Kent Hawryluk | Stock option (right to buy) | A | 164,500 | $0.00 | 164,500 | D | A |
| 20 Jan, 2026 | Laurie Stelzer | Stock option (right to buy) | A | 32,000 | $0.00 | 32,000 | D | A |
| 24 Oct, 2025 | P. Kent Hawryluk | Common Stock | A | 182,859 | $3.25 | 664,256 | D | M |
| 24 Oct, 2025 | P. Kent Hawryluk | Common Stock | A | 182,859 | $3.25 | 664,256 | D | M |
| 24 Oct, 2025 | P. Kent Hawryluk | Stock option (right to buy) | D | 182,859 | $0.00 | 129,708 | D | M |
| 24 Oct, 2025 | P. Kent Hawryluk | Stock option (right to buy) | D | 182,859 | $0.00 | 129,708 | D | M |
| 20 Oct, 2025 | P. Kent Hawryluk | Common Stock | A | 20,000 | $13.64 | 468,277 | I | P |
| 20 Oct, 2025 | P. Kent Hawryluk | Common Stock | A | 20,000 | $13.64 | 468,277 | I | P |