BOLD (Boundless Bio, Inc. Common Stock)
Insider Trading Activity
Every open-market purchase and sale reported by BOLD 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.
| Filed | Insider | Role | Type | Shares | Value |
|---|---|---|---|---|---|
| 2026-08-28 | KEVIN TANG | 10%+ Owner | Sell | — | — |
| 2026-07-21 | TANG CAPITAL MANAGEMENT LLC | 10%+ Owner | Buy | — | — |
| 2026-07-16 | TANG CAPITAL MANAGEMENT LLC | 10%+ Owner | Buy | — | — |
| 2026-07-13 | TANG CAPITAL MANAGEMENT LLC | 10%+ Owner | Buy | — | — |
| 2026-07-08 | TANG CAPITAL MANAGEMENT LLC | 10%+ Owner | Buy | — | — |
| 2026-07-06 | STEVEN GILLIS | 10%+ Owner | MIXED | — | — |
| 2026-07-06 | ARCH Venture Fund IX Overage, L.P. | 10%+ Owner | MIXED | — | — |
| 2026-07-02 | TANG CAPITAL MANAGEMENT LLC | 10%+ Owner | Buy | — | — |
| 2026-06-29 | TANG CAPITAL MANAGEMENT LLC | 10%+ Owner | Buy | — | — |
| 2026-06-15 | James Christensen | Director | A | — | — |
| 2026-06-15 | Jennifer Lew | Director | A | — | — |
| 2026-06-15 | Nancy Whiting | Director | A | — | — |
| 2026-06-15 | Jonathan E Lim | Director | A | — | — |
| 2026-01-26 | DAVID A HINKLE | See Remarks | A | — | — |
| 2026-01-26 | Christian Hassig | Chief Scientific Officer | A | — | — |
| 2026-01-26 | Jessica Oien | See Remarks | A | — | — |
| 2026-01-26 | Zachary Hornby | President & CEO | A | — | — |
| 2026-01-26 | Robert Doebele | Chief Medical Officer | A | — | — |
| 2025-06-23 | Jonathan E Lim | Director | A | — | — |
| 2025-06-23 | Jennifer Lew | Director | A | — | — |
| 2025-06-23 | James Christensen | Director | A | — | — |
| 2025-06-23 | Kristina Burow | Director | A | — | — |
| 2025-06-23 | Nancy Whiting | Director | A | — | — |
| 2025-06-23 | Christine Brennan | Director | A | — | — |
| 2025-02-03 | Robert Doebele | Chief Medical Officer | A | — | — |
| 2025-01-23 | Jessica Oien | See Remarks | A | — | — |
| 2025-01-23 | DAVID A HINKLE | See Remarks | A | — | — |
| 2025-01-23 | Christian Hassig | Chief Scientific Officer | A | — | — |
| 2025-01-23 | Zachary Hornby | President & CEO | A | — | — |
| 2024-08-20 | Zachary Hornby | President & CEO | MIXED | — | — |
| 2024-08-20 | Christian Hassig | Chief Scientific Officer | MIXED | — | — |
| 2024-08-20 | Jessica Oien | See Remarks | MIXED | — | — |
| 2024-08-20 | Jami Rubin | Chief Financial Officer | MIXED | — | — |
| 2024-08-20 | Klaus W. Wagner | Chief Medical Officer | MIXED | — | — |
| 2024-08-20 | Neil Abdollahian | Chief Business Officer | MIXED | — | — |
| 2024-06-20 | Jonathan E Lim | Director | A | — | — |
| 2024-04-04 | Kristina Burow | Director | MIXED | — | — |
| 2024-04-04 | Jonathan E Lim | Director | C | — | — |
| 2024-04-04 | ARCH Venture Partners IX, L.P. | 10%+ Owner | MIXED | — | — |
| 2024-04-04 | ROBERT NELSEN | 10%+ Owner | MIXED | — | — |
| 2024-04-04 | RA CAPITAL MANAGEMENT, L.P. | 10%+ Owner | MIXED | — | — |
| 2024-04-02 | Wellington Biomedical Innovation Master Investors (Cayman) I L.P. | 10%+ Owner | C | — | — |
| 2024-03-29 | Neil Abdollahian | Chief Business Officer | A | — | — |
| 2024-03-29 | Zachary Hornby | President & CEO | A | — | — |
| 2024-03-29 | Jennifer Lew | Director | A | — | — |
| 2024-03-29 | Klaus W. Wagner | Chief Medical Officer | A | — | — |
| 2024-03-29 | Kristina Burow | Director | A | — | — |
| 2024-03-29 | Jami Rubin | Chief Financial Officer | A | — | — |
| 2024-03-29 | James Christensen | Director | A | — | — |
| 2024-03-29 | Jessica Oien | See Remarks | A | — | — |
| Insider | Role | Shares Held | Value |
|---|---|---|---|
| — | 10%+ Owner | 2,858,935 | — |
| — | 10%+ Owner | 2,840,635 | — |
| — | 10%+ Owner | 1,587,912 | — |
| — | 10%+ Owner | 1,181,766 | — |
| — | 10%+ Owner | 1,048,433 | — |
| — | 10%+ Owner | 828,570 | — |
| — | Director | 828,570 | — |
| — | 10%+ Owner | 683,759 | — |
| — | Director | 653,479 | — |
| — | 10%+ Owner | 189,933 | — |
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 BOLD quote page; the site-wide leaderboard is on the insider transactions hub.