MBX Biosciences, Inc. Common Stock (MBX) has 11 known insider and institutional holders on record. The largest holder is Heron Patrick J with 5,219,440 shares. Other notable holders include Hawryluk P. Kent and Stelzer Laurie.
Over the last 12 months, insiders have made 21 transactions in MBX stock — 17 buys (valued at $24.89M) and 0 sells (valued at RSU Award). Insider buying has outpaced selling during this period, which may signal confidence in the company's prospects.
MBX Insider Ownership
Top Holder
Heron Patrick J
5,219,440 shares
Buys (12 mo)
17
$24.89M value
Sells (12 mo)
0
$0.00 value
12-Month Transaction Activity
Top Insider Holders
| # |
Name |
Role |
Shares Owned |
Last Filed |
Relative Size |
| 1 |
Heron Patrick J |
10 Percent Owner |
5,219,440 |
2025-09-30 |
|
| 2 |
Hawryluk P. Kent |
President & CEO |
486,777 |
2026-03-16 |
|
| 3 |
Stelzer Laurie |
Director |
32,000 |
2026-01-22 |
|
| 4 |
Cornelius James M |
Director |
16,000 |
2025-06-06 |
|
| 5 |
Aynechi Tiba |
Director |
16,000 |
2025-06-06 |
|
| 6 |
Pescovitz Ora H. |
Director |
16,000 |
2025-06-06 |
|
| 7 |
Mathers Edward T |
10 Percent Owner |
16,000 |
2025-06-06 |
|
| 8 |
Ryder Steven |
Director |
16,000 |
2025-06-06 |
|
| 9 |
Bartram Richard |
Chief Financial Officer |
15,000 |
2026-02-03 |
|
| 10 |
Azoulay Salomon |
Chief Medical Officer |
15,000 |
2026-02-03 |
|
| 11 |
Hoerter Steven L. |
Director |
8,000 |
2025-11-25 |
|
Recent Transactions (last 12 months)
| Date |
Name |
Role |
Type |
Shares |
Price |
Value |
| 2026-03-16 |
Smither John W |
Officer |
Unknown |
- |
- |
- |
| 2026-03-13 |
Hawryluk P. Kent |
President & CEO |
Informative Buy |
18,500 |
$28.41 |
$525.66K |
| 2026-02-26 |
Hawryluk P. Kent |
President & CEO |
Option Exercise (Sell) |
28,768 |
$16.00 |
$460.29K |
| 2026-02-02 |
Azoulay Salomon |
Chief Medical Officer |
RSU Award |
15,000 |
- |
- |
| 2026-02-02 |
Bartram Richard |
Chief Financial Officer |
RSU Award |
15,000 |
- |
- |
| 2026-02-02 |
Hawryluk P. Kent |
President & CEO |
RSU Award |
164,500 |
$39.07 |
$6.43M |
| 2026-01-20 |
Stelzer Laurie |
Director |
RSU Award |
32,000 |
$43.14 |
$1.38M |
| 2026-01-20 |
Stelzer Laurie |
Officer |
Unknown |
- |
- |
- |
| 2025-11-22 |
Hoerter Steven L. |
Director |
RSU Award |
8,000 |
$27.08 |
$216.64K |
| 2025-11-06 |
Hoerter Steven L. |
Director |
RSU Award |
100,000 |
$24.74 |
$2.47M |
| 2025-10-24 |
Hawryluk P. Kent |
President & CEO |
Option Exercise (Sell) |
182,859 |
$3.25 |
$594.29K |
| 2025-10-20 |
Hawryluk P. Kent |
President & CEO |
Informative Buy |
20,000 |
$13.64 |
$272.79K |
| 2025-10-17 |
Hoerter Steven L. |
Director |
Informative Buy |
20,000 |
$13.25 |
$264.98K |
| 2025-09-26 |
Heron Patrick J |
10 Percent Owner |
Informative Buy |
666,666 |
$18.00 |
$12M |
| 2025-06-05 |
Ryder Steven |
Director |
RSU Award |
16,000 |
$11.86 |
$189.76K |
| 2025-06-05 |
Aynechi Tiba |
Director |
RSU Award |
16,000 |
$11.86 |
$189.76K |
| 2025-06-05 |
Hoerter Steven L. |
Director |
RSU Award |
16,000 |
$11.86 |
$189.76K |
| 2025-06-05 |
Pescovitz Ora H. |
Director |
RSU Award |
16,000 |
$11.86 |
$189.76K |
| 2025-06-05 |
Heron Patrick J |
10 Percent Owner |
RSU Award |
16,000 |
$11.86 |
$189.76K |
| 2025-06-05 |
Mathers Edward T |
10 Percent Owner |
RSU Award |
16,000 |
$11.86 |
$189.76K |
| 2025-06-05 |
Cornelius James M |
Director |
RSU Award |
16,000 |
$11.86 |
$189.76K |
