BOLD insider transaction filings
Boundless Bio, Inc. — 50 most recent Form 4 filings from SEC EDGAR, normalized by FilingPulse. Latest filing: 2026-08-28. Screen BOLD transaction legs live →
Insider transaction summary — last 90 days
2026-06-24 to 2026-09-22, from the filings listed below: 9 Form 4 filings. Counts and totals are arithmetic on values as filed — descriptive data, not a recommendation.
- Open-market purchases (code P, non-derivative): 22 legs across 6 filings by 2 insiders — 611,423 shares, $1,515,094 total (shares × price as filed).
- Open-market sales (code S, non-derivative): 3 legs across 3 filings by 15 insiders — 50,300 shares, $134,031 total (shares × price as filed).
- Other reported legs (grants, option exercises, tax withholding, gifts, derivative-security transactions, …): 4.
- Largest priced transaction: purchase of 145,880 shares @ $2.48 ($361,782) by TANG KEVIN, filed 2026-06-29.
By insider — same window
Open-market purchase/sale legs on non-derivative securities, grouped by the filing's reporting owner(s); joint filings appear once. Dollar totals cover priced legs only (shares × price as filed). Ordered by priced transaction value, largest first.
| Insider | Filings | Purchases (P) | Sales (S) | Other legs |
|---|---|---|---|---|
| TANG KEVIN — 10% owner & TANG CAPITAL MANAGEMENT LLC — 10% owner | 7 | 22 legs · 611,423 sh · $1,515,094 | 1 leg · 18,300 sh · $54,351 | — |
| ARCH Venture Fund IX, L.P. — 10% owner & ARCH Venture Fund IX Overage, L.P. — 10% owner & ARCH Venture Fund X Overage, L.P. — 10% owner & ARCH Venture Partners IX, L.P. — 10% owner & ARCH Venture Partners IX Overage, L.P. — 10% owner & ARCH Venture Partners X Overage, L.P. — 10% owner & ARCH Venture Partners IX, LLC — 10% owner & ARCH Venture Partners X, LLC — 10% owner | 1 | — | 1 leg · 16,000 sh · $39,840 | 2 |
| CRANDELL KEITH — 10% owner & BYBEE CLINTON — 10% owner & NELSEN ROBERT — 10% owner & GILLIS STEVEN — 10% owner & Burow Kristina — 10% owner | 1 | — | 1 leg · 16,000 sh · $39,840 | 2 |
Recent Form 4 filings — Boundless Bio, Inc.
| Filed | Form | Insider | Reported transactions | Source |
|---|---|---|---|---|
| 2026-08-28 | 4 | TANG KEVIN — 10% owner TANG CAPITAL MANAGEMENT LLC — 10% owner | Sale (S): 18,300 @ $2.97 | EDGAR |
| 2026-07-21 | 4 | TANG KEVIN — 10% owner TANG CAPITAL MANAGEMENT LLC — 10% owner | Purchase (P): 265 @ $2.44 · Purchase (P): 1,623 @ $2.44 · Purchase (P): 2,975 @ $2.44 | EDGAR |
| 2026-07-16 | 4 | TANG KEVIN — 10% owner TANG CAPITAL MANAGEMENT LLC — 10% owner | Purchase (P): 43,878 @ $2.43 · Purchase (P): 1,600 @ $2.44 · Purchase (P): 18,491 @ $2.44 | EDGAR |
| 2026-07-13 | 4 | TANG KEVIN — 10% owner TANG CAPITAL MANAGEMENT LLC — 10% owner | Purchase (P): 7 @ $2.48 · Purchase (P): 43,367 @ $2.43 · Purchase (P): 48,211 @ $2.42 | EDGAR |
| 2026-07-08 | 4 | TANG KEVIN — 10% owner TANG CAPITAL MANAGEMENT LLC — 10% owner | Purchase (P): 27,062 @ $2.49 · Purchase (P): 15,810 @ $2.48 · Purchase (P): 14,338 @ $2.46 | EDGAR |
| 2026-07-06 | 4 | ARCH Venture Fund IX, L.P. — 10% owner ARCH Venture Fund IX Overage, L.P. — 10% owner ARCH Venture Fund X Overage, L.P. — 10% owner ARCH Venture Partners IX, L.P. — 10% owner ARCH Venture Partners IX Overage, L.P. — 10% owner ARCH Venture Partners X Overage, L.P. — 10% owner ARCH Venture Partners IX, LLC — 10% owner ARCH Venture Partners X, LLC — 10% owner | Option exercise (M): 16,000 @ $1.03 · Sale (S): 16,000 @ $2.49 · Option exercise (M): 16,000 (derivative) @ $0 | EDGAR |
| 2026-07-06 | 4 | CRANDELL KEITH — 10% owner BYBEE CLINTON — 10% owner NELSEN ROBERT — 10% owner GILLIS STEVEN — 10% owner Burow Kristina — 10% owner | Option exercise (M): 16,000 @ $1.03 · Sale (S): 16,000 @ $2.49 · Option exercise (M): 16,000 (derivative) @ $0 | EDGAR |
| 2026-07-02 | 4 | TANG KEVIN — 10% owner TANG CAPITAL MANAGEMENT LLC — 10% owner | Purchase (P): 25,930 @ $2.54 · Purchase (P): 100 @ $2.50 · Purchase (P): 71,612 @ $2.49 · Purchase (P): 9,821 @ $2.49 | EDGAR |
| 2026-06-29 | 4 | TANG KEVIN — 10% owner TANG CAPITAL MANAGEMENT LLC — 10% owner | Purchase (P): 145,880 @ $2.48 · Purchase (P): 510 @ $2.56 · Purchase (P): 75,047 @ $2.55 · Purchase (P): 134 @ $2.54 · Purchase (P): 63,985 @ $2.47 · Purchase (P): 777 @ $2.48 | EDGAR |
| 2026-06-15 | 4 | Whiting Nancy — Director | Grant/award (A): 32,000 (derivative) @ $0 | EDGAR |
| 2026-06-15 | 4 | Christensen James — Director | Grant/award (A): 32,000 (derivative) @ $0 | EDGAR |
| 2026-06-15 | 4 | Lew Jennifer — Director | Grant/award (A): 32,000 (derivative) @ $0 | EDGAR |
| 2026-06-15 | 4 | Lim Jonathan E — Director | Grant/award (A): 48,000 (derivative) @ $0 | EDGAR |
| 2026-01-26 | 4 | Doebele Robert — Chief Medical Officer | Grant/award (A): 230,000 (derivative) @ $0 | EDGAR |
| 2026-01-26 | 4 | Oien Jessica — See Remarks | Grant/award (A): 220,000 (derivative) @ $0 | EDGAR |
| 2026-01-26 | 4 | Hassig Christian — Chief Scientific Officer | Grant/award (A): 230,000 (derivative) @ $0 | EDGAR |
| 2026-01-26 | 4 | Hornby Zachary — President & CEO, Director | Grant/award (A): 600,000 (derivative) @ $0 | EDGAR |
| 2026-01-26 | 4 | HINKLE DAVID A — See Remarks | Grant/award (A): 140,000 (derivative) @ $0 | EDGAR |
| 2025-06-23 | 4 | Brennan Christine — Director | Grant/award (A): 16,000 (derivative) @ $0 | EDGAR |
| 2025-06-23 | 4 | Christensen James — Director | Grant/award (A): 16,000 (derivative) @ $0 | EDGAR |
| 2025-06-23 | 4 | Whiting Nancy — Director | Grant/award (A): 16,000 (derivative) @ $0 | EDGAR |
| 2025-06-23 | 4 | Burow Kristina — Director, 10% owner | Grant/award (A): 16,000 (derivative) @ $0 | EDGAR |
| 2025-06-23 | 4 | Lew Jennifer — Director | Grant/award (A): 16,000 (derivative) @ $0 | EDGAR |
| 2025-06-23 | 4 | Lim Jonathan E — Director | Grant/award (A): 24,000 (derivative) @ $0 | EDGAR |
| 2025-02-03 | 4 | Doebele Robert — Chief Medical Officer | Grant/award (A): 180,000 (derivative) @ $0 | EDGAR |
| 2025-01-23 | 4 | Oien Jessica — See Remarks | Grant/award (A): 90,000 (derivative) @ $0 | EDGAR |
| 2025-01-23 | 4 | Hassig Christian — Chief Scientific Officer | Grant/award (A): 95,000 (derivative) @ $0 | EDGAR |
| 2025-01-23 | 4 | Hornby Zachary — President & CEO, Director | Grant/award (A): 295,000 (derivative) @ $0 | EDGAR |
| 2025-01-23 | 4 | HINKLE DAVID A — See Remarks | Grant/award (A): 65,000 (derivative) @ $0 | EDGAR |
| 2024-08-20 | 4 | Rubin Jami — Chief Financial Officer | Disposition to issuer (D): 196,666 (derivative) · Disposition to issuer (D): 51,420 (derivative) · Disposition to issuer (D): 32,468 (derivative) · Grant/award (A): 196,666 (derivative) · Grant/award (A): 51,420 (derivative) · Grant/award (A): 32,468 (derivative) | EDGAR |
| 2024-08-20 | 4 | Wagner Klaus W. — Chief Medical Officer | Disposition to issuer (D): 102,564 (derivative) · Disposition to issuer (D): 9,635 (derivative) · Disposition to issuer (D): 94,871 (derivative) · Disposition to issuer (D): 68,080 (derivative) · Disposition to issuer (D): 41,745 (derivative) · Grant/award (A): 102,564 (derivative) · +4 more | EDGAR |
| 2024-08-20 | 4 | Oien Jessica — See Remarks | Disposition to issuer (D): 32,051 (derivative) · Disposition to issuer (D): 29,148 (derivative) · Disposition to issuer (D): 10,200 (derivative) · Disposition to issuer (D): 42,051 (derivative) · Disposition to issuer (D): 35,897 (derivative) · Disposition to issuer (D): 26,090 (derivative) · +8 more | EDGAR |
| 2024-08-20 | 4 | Hassig Christian — Chief Scientific Officer | Disposition to issuer (D): 10,256 (derivative) · Disposition to issuer (D): 62,820 (derivative) · Disposition to issuer (D): 94,871 (derivative) · Disposition to issuer (D): 76,173 (derivative) · Disposition to issuer (D): 48,703 (derivative) · Grant/award (A): 10,256 (derivative) · +4 more | EDGAR |
| 2024-08-20 | 4 | Abdollahian Neil — Chief Business Officer | Disposition to issuer (D): 82,051 (derivative) · Disposition to issuer (D): 19,948 (derivative) · Disposition to issuer (D): 54,871 (derivative) · Disposition to issuer (D): 36,852 (derivative) · Disposition to issuer (D): 23,191 (derivative) · Grant/award (A): 82,051 (derivative) · +4 more | EDGAR |
| 2024-08-20 | 4 | Hornby Zachary — President & CEO, Director | Disposition to issuer (D): 256,410 (derivative) · Disposition to issuer (D): 471,282 (derivative) · Disposition to issuer (D): 257,207 (derivative) · Disposition to issuer (D): 162,343 (derivative) · Grant/award (A): 256,410 (derivative) · Grant/award (A): 471,282 (derivative) · +2 more | EDGAR |
| 2024-06-20 | 4 | Lim Jonathan E — Director | Grant/award (A): 6,610 (derivative) @ $0 | EDGAR |
| 2024-04-04 | 4 | ARCH Venture Fund IX, L.P. — 10% owner ARCH Venture Fund IX Overage, L.P. — 10% owner ARCH Venture Fund X Overage, L.P. — 10% owner ARCH Venture Partners IX, L.P. — 10% owner ARCH Venture Partners IX Overage, L.P. — 10% owner ARCH Venture Partners X Overage, L.P. — 10% owner ARCH Venture Partners IX, LLC — 10% owner ARCH Venture Partners X, LLC — 10% owner | Conversion (C): 589,743 · Conversion (C): 787,545 · Conversion (C): 1,048,433 · Purchase (P): 66,667 @ $16 · Purchase (P): 133,333 @ $16 · Conversion (C): 424,908 (derivative) · +6 more | EDGAR |
| 2024-04-04 | 4 | Burow Kristina — Director, 10% owner | Conversion (C): 589,743 · Conversion (C): 787,545 · Conversion (C): 1,048,433 · Purchase (P): 66,667 @ $16 · Purchase (P): 133,333 @ $16 · Conversion (C): 424,908 (derivative) · +6 more | EDGAR |
| 2024-04-04 | 4 | Lim Jonathan E — Director | Conversion (C): 525,274 · Conversion (C): 512,820 (derivative) · Conversion (C): 5,128 (derivative) · Conversion (C): 7,326 (derivative) | EDGAR |
| 2024-04-04 | 4 | RA CAPITAL MANAGEMENT, L.P. — 10% owner RA Capital Healthcare Fund LP — 10% owner RA Capital Nexus Fund II, L.P. — 10% owner Kolchinsky Peter — 10% owner Shah Rajeev M. — 10% owner | Conversion (C): 1,587,912 · Purchase (P): 296,875 @ $16 · Conversion (C): 280,219 · Purchase (P): 15,625 @ $16 · Conversion (C): 17,000,000 (derivative) @ $0 · Conversion (C): 3,000,000 (derivative) @ $0 · +2 more | EDGAR |
| 2024-04-04 | 4 | CRANDELL KEITH — 10% owner BYBEE CLINTON — 10% owner NELSEN ROBERT — 10% owner GILLIS STEVEN — 10% owner | Conversion (C): 589,743 · Conversion (C): 787,545 · Conversion (C): 1,048,433 · Purchase (P): 66,667 @ $16 · Purchase (P): 133,333 @ $16 · Conversion (C): 424,908 (derivative) · +6 more | EDGAR |
| 2024-04-02 | 4 | Wellington Biomedical Innovation Master Investors (Cayman) I L.P. — 10% owner | Conversion (C): 189,933 · Conversion (C): 366,300 · Conversion (C): 3,703,704 (derivative) @ $0 · Conversion (C): 7,142,857 (derivative) @ $0 | EDGAR |
| 2024-03-29 | 4 | Wagner Klaus W. — Chief Medical Officer | Grant/award (A): 41,745 (derivative) @ $0 | EDGAR |
| 2024-03-29 | 4 | Oien Jessica — See Remarks | Grant/award (A): 16,234 (derivative) @ $0 | EDGAR |
| 2024-03-29 | 4 | Hassig Christian — Chief Scientific Officer | Grant/award (A): 48,703 (derivative) @ $0 | EDGAR |
| 2024-03-29 | 4 | Abdollahian Neil — Chief Business Officer | Grant/award (A): 23,191 (derivative) @ $0 | EDGAR |
| 2024-03-29 | 4 | Hornby Zachary — President & CEO, Director | Grant/award (A): 162,343 (derivative) @ $0 | EDGAR |
| 2024-03-29 | 4 | Burow Kristina — Director, 10% owner | Grant/award (A): 26,438 (derivative) @ $0 | EDGAR |
| 2024-03-29 | 4 | Lew Jennifer — Director | Grant/award (A): 13,219 (derivative) @ $0 | EDGAR |
| 2024-03-29 | 4 | Lim Jonathan E — Director | Grant/award (A): 13,219 (derivative) @ $0 | EDGAR |
Recent 8-K events — Boundless Bio, Inc.
| Filed | Form | Items reported | Source |
|---|---|---|---|
| 2026-08-28 | 8-K | 1.01 — Entry into a Material Definitive Agreement 9.01 — Financial Statements and Exhibits | EDGAR |
| 2026-06-23 | 8-K | 1.01 — Entry into a Material Definitive Agreement ? 3.02 — Unregistered Sales of Equity Securities 5.01 — Changes in Control of Registrant 5.02 — Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers 7.01 — Regulation FD Disclosure 8.01 — Other Events 9.01 — Financial Statements and Exhibits | EDGAR |
| 2026-06-17 | 8-K | 5.07 — Submission of Matters to a Vote of Security Holders | EDGAR |
| 2026-05-08 | 8-K | 2.02 — Results of Operations and Financial Condition 9.01 — Financial Statements and Exhibits | EDGAR |
| 2026-04-13 | 8-K | 1.02 — Termination of a Material Definitive Agreement 2.03 — Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant | EDGAR |
| 2026-03-09 | 8-K | 2.02 — Results of Operations and Financial Condition 5.02 — Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers 9.01 — Financial Statements and Exhibits | EDGAR |
| 2025-11-05 | 8-K | 2.02 — Results of Operations and Financial Condition 9.01 — Financial Statements and Exhibits | EDGAR |
| 2025-08-05 | 8-K | 2.02 — Results of Operations and Financial Condition 9.01 — Financial Statements and Exhibits | EDGAR |
| 2025-06-23 | 8-K | 5.07 — Submission of Matters to a Vote of Security Holders | EDGAR |
| 2025-05-23 | 8-K | ? 8.01 — Other Events | EDGAR |
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