15 insiders reported 34 Form 4 transactions for Boundless Bio, Inc. (BOLD) over the past 18 months (most recent 2026-07-06). Recent activity: GILLIS STEVEN (Insider) Buy 16,000 shares, ARCH Venture Fund IX, L.P. (Insider) Sell 16,000 shares, ARCH Venture Partners IX, LLC (Insider) Buy 16,000 shares, ARCH Venture Partners X, LLC (Insider) Buy 16,000 shares, ARCH Venture Partners IX Overage, L.P. (Insider) Buy 16,000 shares. Source: SEC Form 4.
| Date | Insider | Title | Type | Shares | Value |
|---|---|---|---|---|---|
| 2026-07-06 | GILLIS STEVEN | Insider | Buy | 16,000 | $16,480 |
| 2026-07-06 | ARCH Venture Fund IX, L.P. | Insider | Sell | 16,000 | $39,840 |
| 2026-07-06 | ARCH Venture Partners IX, LLC | Insider | Buy | 16,000 | $16,480 |
| 2026-07-06 | ARCH Venture Partners X, LLC | Insider | Buy | 16,000 | $16,480 |
| 2026-07-06 | ARCH Venture Partners IX Overage, L.P. | Insider | Buy | 16,000 | $16,480 |
| 2026-07-06 | ARCH Venture Partners X Overage, L.P. | Insider | Buy | 16,000 | $16,480 |
| 2026-07-06 | ARCH Venture Fund IX Overage, L.P. | Insider | Buy | 16,000 | $16,480 |
| 2026-07-06 | ARCH Venture Partners IX, L.P. | Insider | Buy | 16,000 | $16,480 |
| 2026-07-06 | CRANDELL KEITH | Insider | Buy | 16,000 | $16,480 |
| 2026-07-06 | ARCH Venture Fund IX, L.P. | Insider | Buy | 16,000 | $16,480 |
| 2026-07-06 | NELSEN ROBERT | Insider | Buy | 16,000 | $16,480 |
| 2026-07-06 | Burow Kristina | Insider | Buy | 16,000 | $16,480 |
| 2026-07-06 | BYBEE CLINTON | Insider | Buy | 16,000 | $16,480 |
| 2026-07-06 | ARCH Venture Partners X, LLC | Insider | Sell | 16,000 | $39,840 |
| 2026-07-06 | BYBEE CLINTON | Insider | Sell | 16,000 | $39,840 |
| 2026-07-06 | GILLIS STEVEN | Insider | Sell | 16,000 | $39,840 |
| 2026-07-06 | NELSEN ROBERT | Insider | Sell | 16,000 | $39,840 |
| 2026-07-06 | Burow Kristina | Insider | Sell | 16,000 | $39,840 |
| 2026-07-06 | ARCH Venture Partners IX, LLC | Insider | Sell | 16,000 | $39,840 |
| 2026-07-06 | ARCH Venture Partners IX, L.P. | Insider | Sell | 16,000 | $39,840 |
| 2026-07-06 | ARCH Venture Fund X Overage, L.P. | Insider | Sell | 16,000 | $39,840 |
| 2026-07-06 | ARCH Venture Fund IX Overage, L.P. | Insider | Sell | 16,000 | $39,840 |
| 2026-07-06 | ARCH Venture Partners X Overage, L.P. | Insider | Sell | 16,000 | $39,840 |
| 2026-07-06 | ARCH Venture Partners IX Overage, L.P. | Insider | Sell | 16,000 | $39,840 |
| 2026-07-06 | ARCH Venture Fund X Overage, L.P. | Insider | Buy | 16,000 | $16,480 |
Source: SEC Form 4 filings · as of 2026-07-06