MBX (MBX Biosciences, Inc. Common Stock)

Insider Trading Activity

Every open-market purchase and sale reported by MBX officers, directors and 10%+ beneficial owners on SEC Form 4, which must be filed within two business days of the transaction. Sales often reflect scheduled 10b5-1 plans or tax withholding rather than a directional view, so read counts alongside the size and the filer.

Market data may be delayed, incomplete, or inaccurate. Not a recommendation to buy, sell, or hold any security. Verify quotes with your broker before trading. See Terms §17.

Form 4 Filings
50
most recent
Open-Market Buys
8
code P
Sales
3
code S
Reporting Insiders
25
current holders
MBX — Recent Form 4 Transactions (latest 2026-08-05)
FiledInsiderRole TypeSharesValue
2026-08-05 Salomon Azoulay Chief Medical Officer Sell
2026-08-04 John W Smither Chief Financial Officer A
2026-08-04 Steven L. Hoerter President and CEO A
2026-06-05 Patrick J Heron Director A
2026-06-05 Laurie Stelzer Director A
2026-06-05 Edward T Mathers Director A
2026-06-05 Ora H. Pescovitz Director A
2026-06-05 Tiba Aynechi Director A
2026-06-05 Steven Ryder Director A
2026-06-05 Steven L. Hoerter Director A
2026-05-11 Salomon Azoulay Chief Medical Officer MIXED
2026-05-08 P. Kent Hawryluk President & CEO Sell
2026-05-08 Salomon Azoulay Chief Medical Officer Sell
2026-05-04 Steven L. Hoerter Director A
2026-04-22 Steven L. Hoerter Director A
2026-04-22 Steven L. Hoerter Director A
2026-03-16 P. Kent Hawryluk President & CEO Buy
2026-02-27 P. Kent Hawryluk President & CEO M
2026-02-03 P. Kent Hawryluk President & CEO A
2026-02-03 Salomon Azoulay Chief Medical Officer A
2026-02-03 Richard Bartram Chief Financial Officer A
2026-01-22 Laurie Stelzer Director A
2025-11-25 Steven L. Hoerter Director A
2025-11-07 Steven L. Hoerter Director A
2025-10-28 P. Kent Hawryluk President & CEO M
2025-10-21 P. Kent Hawryluk President & CEO Buy
2025-10-20 Steven L. Hoerter Director Buy
2025-09-30 Frazier Life Sciences X, L.P. 10%+ Owner Buy
2025-06-06 JAMES M CORNELIUS Director A
2025-06-06 Patrick J Heron Director A
2025-06-06 Steven L. Hoerter Director A
2025-06-06 Steven Ryder Director A
2025-06-06 Edward T Mathers Director A
2025-06-06 Tiba Aynechi Director A
2025-06-06 Ora H. Pescovitz Director A
2025-04-10 Ora H. Pescovitz Director Buy
2025-04-09 Steven L. Hoerter Director A
2025-02-19 CARL L GORDON Director Buy
2025-02-19 OrbiMed Capital GP VII LLC Director Buy
2025-02-05 Salomon Azoulay Chief Medical Officer A
2025-02-05 Richard Bartram Chief Financial Officer A
2025-02-05 P. Kent Hawryluk President & CEO Buy
2024-09-17 JAMES M CORNELIUS Director C
2024-09-17 Tiba Aynechi Director MIXED
2024-09-17 CARL L GORDON Director MIXED
2024-09-17 Carmen Chang 10%+ Owner MIXED
2024-09-17 Patrick J Heron Director MIXED
2024-09-17 FOREST BASKETT 10%+ Owner MIXED
2024-09-17 P. Kent Hawryluk President & CEO C
2024-09-17 Paul Edward Walker 10%+ Owner MIXED
MBX — Current Insider Holders
InsiderRole Shares HeldValue
10%+ Owner 5,219,440
10%+ Owner 4,552,774
Director 3,927,774
10%+ Owner 3,614,486
10%+ Owner 3,614,486
Director 3,205,930
10%+ Owner 3,114,486
10%+ Owner 3,114,486
10%+ Owner 3,114,486
10%+ Owner 3,114,486
10%+ Owner 1,790,122
Director 1,386,335
President & CEO 1,214,444
10%+ Owner 1,023,103
Director 1,023,103
10%+ Owner 1,023,103
10%+ Owner 1,023,103
Director 747,887
Director 653,787
President and CEO 102,938
Director 102,082
Chief Financial Officer 28,000
Director 24,329
Chief Financial Officer 15,000
Chief Medical Officer 14,399
How to read Form 4 activity

Form 4 reports a change in beneficial ownership by an officer, director or 10%+ holder, and must be filed within two business days of the transaction — so this is close to real time, unlike the 45-day-lagged 13F institutional data.

Transaction codes matter more than the raw buy/sell count. Code P is an open-market purchase — an insider choosing to buy with their own money, which is the signal most research treats as informative. Code S is a sale, but sales are frequently pre-scheduled under a 10b5-1 plan or cover tax withholding on vesting equity, so a run of sales often says nothing directional. Codes A and M are grants and option exercises rather than open-market decisions.

Full filing history and per-insider positions are on the MBX quote page; the site-wide leaderboard is on the insider transactions hub.