James N Topper insider trades: MBX Biosciences (MBX) stock buys and sales
Trades on the price chart
Daily close, with an arrow on each day they bought or sold
Companies
Where James reports to the SEC
and 15 more companies
Open-market buys and sales
75 trades reported on SEC Form 4, newest first
| Date | Stock | Type | Shares | Price | Value | Holding | Reported |
|---|---|---|---|---|---|---|---|
| Sep 26, 2025 | MBX | ↑ Buy | 666,666 | $18.00 | $12.0M | By Frazier Life Sciences X, L.P. | Sep 30, 2025 (4d) |
| Sep 15, 2025 | NAMS | ↑ Buy | 660 | $23.70 | $16K | By Frazier Life Sciences X, L.P. | Sep 17, 2025 (2d) |
| Sep 8, 2025 | NAMS | ↑ Buy | 1,260 | $24.99 | $31K | By Frazier Life Sciences X, L.P. | Sep 10, 2025 (2d) |
| Aug 11, 2025 | NAMS | ↑ Buy | 471 | $23.98 | $11K | By Frazier Life Sciences X, L.P. | Aug 13, 2025 (2d) |
| Jun 25, 2025 | NAMS | ↑ Buy | 3,780 | $18.38 | $69K | By Frazier Life Sciences X, L.P. | Jun 26, 2025 (1d) |
| Jun 16, 2025 | NAMS | ↑ Buy | 8,584 | $19.50 | $167K | By Frazier Life Sciences X, L.P. | Jun 18, 2025 (2d) |
| May 21, 2025 | PHAT | ↑ Buy | 3,780 | $3.86 | $15K | By Frazier Life Sciences X, L.P. | May 23, 2025 (2d) |
| May 14, 2025 | PHAT | ↑ Buy | 7,420 | $3.30 | $24K | By Frazier Life Sciences X, L.P. | May 15, 2025 (1d) |
| May 12, 2025 | PHAT | ↑ Buy | 48,203 | $3.17 | $153K | By Frazier Life Sciences X, L.P. | May 13, 2025 (1d) |
| Mar 26, 2025 | NAMS | ↑ Buy | 1,135 | $22.49 | $26K | By Frazier Life Sciences X, L.P. | Mar 28, 2025 (2d) |
| Mar 4, 2025 | NAMS | ↑ Buy | 4,005 | $21.02 | $84K | By Frazier Life Sciences X, L.P. | Mar 6, 2025 (2d) |
| Sep 16, 2024 | MBX | ↑ Buy | 625,000 | $16.00 | $10.0M | Direct | Sep 17, 2024 (1d) |
| Apr 25, 2024 | ALPN | ↓ Sell | 19 | $64.57 | $1K | By: Frazier Life Sciences VIII, L.P. | Apr 29, 2024 (4d) |
| Apr 4, 2024 | HLVX | ↑ Buy | 8,850 | $14.50 | $128K | Direct | Apr 8, 2024 (4d) |
| Mar 26, 2024 | NAMS | ↑ Buy | 8,429 | $21.50 | $181K | By Frazier Life Sciences X, L.P. | Mar 28, 2024 (2d) |
| Oct 24, 2023 | ARQT | ↑ Buy | 80,000 | $2.50 | $200K | Direct | Oct 26, 2023 (2d) |
| Aug 5, 2022 | ARQT | ↑ Buy | 250,000 | $20.00 | $5.0M | Direct | Aug 9, 2022 (4d) |
| May 3, 2022 | HLVX | ↑ Buy | 1,764,706 | $17.00 | $30.0M | Direct | May 3, 2022 (0d) |
| Feb 11, 2022 | ALPN | ↑ Buy | 112,665 | $7.10 | $800K | Direct | Feb 15, 2022 (4d) |
| Dec 11, 2020 | FLAC | ↑ Buy | 1,000,000 | $10.00 | $10.0M | Direct | Dec 11, 2020 (0d) |
| Oct 20, 2020 | TARS | ↑ Buy | 312,500 | $16.00 | $5.0M | Direct | Oct 20, 2020 (0d) |
| Mar 3, 2020 | PASG | ↑ Buy | 550,000 | $18.00 | $9.9M | Direct | Mar 3, 2020 (0d) |
| Feb 4, 2020 | ARQT | ↑ Buy | 500,000 | $17.00 | $8.5M | Direct | Feb 6, 2020 (2d) |
| Jan 9, 2020 | ETTX | ↓ Sell | 50,000 | $5.00 | $250K | Direct | Jan 13, 2020 (4d) |
| Oct 29, 2019 | PHAT | ↑ Buy | 1,052,631 | $19.00 | $20.0M | Direct | Oct 30, 2019 (1d) |
| Jul 22, 2019 | MIRM | ↑ Buy | 450,000 | $15.00 | $6.8M | Direct | Jul 24, 2019 (2d) |
| Jan 18, 2019 | ALPN | ↑ Buy | 372,439 | $5.37 | $2.0M | By Frazier Life Sciences VIII, L.P. | Jan 22, 2019 (4d) |
| Sep 28, 2018 | ETTX | ↑ Buy | 375,887 | $15.00 | $5.6M | Indirect | Oct 2, 2018 (4d) |
| Jun 25, 2018 | APTX | ↑ Buy | 150,000 | $16.00 | $2.4M | Indirect | Jun 26, 2018 (1d) |
| Nov 6, 2017 | ALNA | ↑ Buy | 500,000 | $14.00 | $7.0M | Indirect | Nov 6, 2017 (0d) |
| Feb 14, 2017 | SRRA | ↑ Buy | 5,925,926 | $1.35 | $8.0M | By Frazier Life Sciences VIII, L.P. | Feb 16, 2017 (2d) |
| Jan 31, 2017 | ANAB | ↑ Buy | 400,000 | $15.00 | $6.0M | Indirect | Jan 31, 2017 (0d) |
| Jul 21, 2015 | DNAI | ↑ Buy | 220,000 | $17.00 | $3.7M | By Frazier Healthcare VI, L.P. | Jul 21, 2015 (0d) |
| May 12, 2015 | COLL | ↑ Buy | 150,000 | $12.00 | $1.8M | Direct | May 14, 2015 (2d) |
| Feb 26, 2009 | LJPC | ↓ Sell | 5,872,711 | $0.06 | $368K | Frazier Healthcare V, LP | Feb 26, 2009 (0d) |
| Mar 10, 2008 | FOLD | ↑ Buy | 22,906 | $10.01 | $229K | By Frazier Healthcare V, LP | Mar 10, 2008 (0d) |
| Mar 10, 2008 | FOLD | ↑ Buy | 4,740 | $10.27 | $49K | By Frazier Healthcare V, LP | Mar 10, 2008 (0d) |
| Mar 5, 2008 | FOLD | ↑ Buy | 37,992 | $9.78 | $372K | By Frazier Healthcare V, LP | Mar 5, 2008 (0d) |
| Mar 5, 2008 | FOLD | ↑ Buy | 21,008 | $9.81 | $206K | By Frazier Healthcare V, LP | Mar 5, 2008 (0d) |
| Mar 4, 2008 | FOLD | ↑ Buy | 22,926 | $1080.19 | $24.8M | By Frazier Healthcare V, LP | Mar 5, 2008 (1d) |
| Mar 3, 2008 | FOLD | ↑ Buy | 43,674 | $9.67 | $422K | By Frazier Healthcare V, LP | Mar 5, 2008 (2d) |
| Feb 29, 2008 | FOLD | ↑ Buy | 8,637 | $9.88 | $85K | By Frazier Healthcare V, LP | Mar 4, 2008 (4d) |
| Feb 28, 2008 | FOLD | ↑ Buy | 10,638 | $10.03 | $107K | By Frazier Healthcare V, LP | Feb 28, 2008 (0d) |
| Feb 28, 2008 | FOLD | ↑ Buy | 5,762 | $10.08 | $58K | By Frazier Healthcare IV, LP | Feb 28, 2008 (0d) |
| Feb 27, 2008 | FOLD | ↑ Buy | 16,600 | $9.82 | $163K | By Frazier Healthcare V, LP | Feb 28, 2008 (1d) |
| Feb 26, 2008 | FOLD | ↑ Buy | 6,100 | $9.71 | $59K | By Frazier Healthcare V, LP | Feb 28, 2008 (2d) |
| Feb 25, 2008 | FOLD | ↑ Buy | 9,900 | $9.67 | $96K | By Frazier Healthcare V, LP | Feb 25, 2008 (0d) |
| Feb 22, 2008 | FOLD | ↑ Buy | 7,500 | $10.06 | $75K | By Frazier Healthcare V, LP | Feb 25, 2008 (3d) |
| Feb 22, 2008 | FOLD | ↑ Buy | 6,614 | $9.86 | $65K | By Frazier Healthcare V, LP | Feb 25, 2008 (3d) |
| Feb 20, 2008 | FOLD | ↑ Buy | 49,500 | $9.62 | $476K | By Frazier Healthcare V, LP | Feb 20, 2008 (0d) |
Each row is one filing's trades in one stock, summed. Shares and prices are as filed, before any later stock split.
Other MBX insiders
Open-market trades in the last 12 months
About James N Topper's insider trades
James N Topper is a 10% owner of MBX Biosciences (MBX). Since Dec 14, 2005, James has reported 72 open-market purchases worth $209.7M and 3 sales worth $619K on SEC Form 4. There have been no open-market trades in the last 12 months.
Their filings also include grants and awards (46 filings), conversions (16 filings), other transactions (10 filings), option exercises (4 filings). These aren't open-market trades and aren't counted above.
How to read insider trades
Officers, directors and owners of more than 10% of a company must report trades in its stock on SEC Form 4, usually within two business days. Purchases with their own money are the stronger signal: insiders sell for many reasons (taxes, diversification, a house), but buy for one. See every MBX insider trade, the latest insider trades across the market, or cluster buys, when several insiders buy the same stock within days.