NELSEN ROBERT — SEC Form 4 filings

SEC reporting owner CIK 1219042. 24 Form 4 filings on record with FilingPulse; latest filed 2026-07-06.

Transaction summary — filings shown

Covers all 24 filings on record, filed 2024-02-12 to 2026-07-06. Counts and totals are arithmetic on values as filed — descriptive data, not a recommendation.

By issuer — same filings

Open-market purchase/sale legs on non-derivative securities, grouped by issuer. Role is as filed on the newest filing for that issuer. Dollar totals cover priced legs only (shares × price as filed). Ordered by priced transaction value, largest first.

IssuerRole (as filed)FilingsPurchases (P)Sales (S)Other legs
Metsera, Inc. (MTSR)Director, 10% owner22 legs · 2,222,222 sh · $39,999,9969
Prime Medicine, Inc. (PRME)Director, 10% owner62 legs · 6,230,300 sh · $29,999,9907
Kardigan, Inc. (KARD)Director, 10% owner21 leg · 1,250,000 sh · $20,000,0004
Seaport Therapeutics, Inc. (SPTX)10% owner11 leg · 1,100,000 sh · $19,800,0004
Lyell Immunopharma, Inc. (LYEL)10% owner31 leg · 488,090 sh · $12,499,9851
Sana Biotechnology, Inc. (SANA)Director, 10% owner53 legs · 1,818,181 sh · $9,999,9964
Neumora Therapeutics, Inc. (NMRA)10% owner11 leg · 1,915,700 sh · $4,999,977
Boundless Bio, Inc. (BOLD)10% owner22 legs · 200,000 sh · $3,200,0001 leg · 16,000 sh · $39,84012
Rapport Therapeutics, Inc. (RAPP)10% owner13
Vir Biotechnology, Inc. (VIR)Director12

Form 4 filings — NELSEN ROBERT

FiledFormIssuerReported transactionsSource
2026-07-064Boundless Bio, Inc. (BOLD)
jointly with CRANDELL KEITH, BYBEE CLINTON, GILLIS STEVEN, Burow Kristina
Option exercise (M): 16,000 @ $1.03 · Sale (S): 16,000 @ $2.49 · Option exercise (M): 16,000 (derivative) @ $0EDGAR
2026-06-244Kardigan, Inc. (KARD)
jointly with ARCH Venture Partners XIII, LLC, ARCH Venture Partners XIII, L.P., ARCH Venture Fund XIII, L.P., CRANDELL KEITH, Burow Kristina, GILLIS STEVEN
Purchase (P): 1,250,000 @ $16EDGAR
2026-06-224Kardigan, Inc. (KARD)
jointly with ARCH Venture Partners XIII, LLC, ARCH Venture Partners XIII, L.P., ARCH Venture Fund XIII, L.P., CRANDELL KEITH, Burow Kristina, GILLIS STEVEN
Conversion (C): 13,792,035 · Conversion (C): 5,148,587 (derivative) · Conversion (C): 1,204,000 (derivative) · Conversion (C): 2,306,401 (derivative)EDGAR
2026-06-084Prime Medicine, Inc. (PRME)Grant/award (A): 75,000 (derivative) @ $0EDGAR
2026-06-054Sana Biotechnology, Inc. (SANA)Grant/award (A): 90,000 (derivative) @ $0EDGAR
2026-05-044Seaport Therapeutics, Inc. (SPTX)
jointly with ARCH Venture Partners XII, LLC, ARCH Venture Partners XII, L.P., ARCH Venture Fund XII, L.P., CRANDELL KEITH, Burow Kristina, GILLIS STEVEN
Conversion (C): 2,513,686 · Conversion (C): 2,681,265 · Purchase (P): 1,100,000 @ $18 · Conversion (C): 2,513,686 (derivative) @ $0 · Conversion (C): 2,681,265 (derivative) @ $0EDGAR
2026-03-094Lyell Immunopharma, Inc. (LYEL)
jointly with ARCH Venture Fund XIII, L.P., ARCH Venture Partners XIII, L.P., ARCH Venture Partners XIII, LLC, CRANDELL KEITH, Burow Kristina, GILLIS STEVEN, BERNS PAUL L, BYBEE CLINTON
Purchase (P): 488,090 @ $25.61EDGAR
2025-11-144Metsera, Inc. (MTSR)
jointly with ARCH Venture Partners XII, LLC, ARCH Venture Fund XII, L.P., ARCH Venture Partners XII, L.P., ARCH Venture Fund XIII, L.P., ARCH Venture Partners XIII, L.P., ARCH Venture Partners XIII, LLC, CRANDELL KEITH, GILLIS STEVEN
Disposition to issuer (D): 18,503,128 · Disposition to issuer (D): 8,313,680EDGAR
2025-10-294Neumora Therapeutics, Inc. (NMRA)
jointly with ARCH Venture Partners XII, LLC, ARCH Venture Partners XII, L.P., ARCH Venture Fund XII, L.P., CRANDELL KEITH, GILLIS STEVEN, BYBEE CLINTON
Purchase (P): 1,915,700 @ $2.61EDGAR
2025-08-054Prime Medicine, Inc. (PRME)Disposition to issuer (D): 39,062 (derivative) · Grant/award (A): 39,062 (derivative) · Disposition to issuer (D): 45,000 (derivative) · Grant/award (A): 45,000 (derivative)EDGAR
2025-08-014Prime Medicine, Inc. (PRME)Purchase (P): 3,030,300 @ $3.30EDGAR
2025-07-294Lyell Immunopharma, Inc. (LYEL)
jointly with ARCH Venture Partners IX, LLC, ARCH Venture Partners IX, L.P., ARCH Venture Partners IX Overage, L.P., ARCH Venture Fund IX, L.P., ARCH Venture Fund IX Overage, L.P., CRANDELL KEITH, BYBEE CLINTON
Holdings only — no transactions reportedEDGAR
2025-06-094Sana Biotechnology, Inc. (SANA)Grant/award (A): 80,000 (derivative) @ $0EDGAR
2025-06-054Prime Medicine, Inc. (PRME)Grant/award (A): 55,000 (derivative) @ $0EDGAR
2025-02-034Metsera, Inc. (MTSR)
jointly with ARCH Venture Partners XII, LLC, ARCH Venture Fund XII, L.P., ARCH Venture Partners XII, L.P., ARCH Venture Fund XIII, L.P., ARCH Venture Partners XIII, L.P., ARCH Venture Partners XIII, LLC, CRANDELL KEITH, GILLIS STEVEN
Conversion (C): 16,006,949 · Conversion (C): 7,523,682 · Purchase (P): 1,432,224 @ $18 · Purchase (P): 789,998 @ $18 · Conversion (C): 19,933,333 (derivative) · Conversion (C): 15,000,000 (derivative) · +3 moreEDGAR
2024-07-154/ASana Biotechnology, Inc. (SANA)Grant/award (A): 65,000 (derivative) @ $0EDGAR
2024-06-174Lyell Immunopharma, Inc. (LYEL)Grant/award (A): 130,000 (derivative) @ $0EDGAR
2024-06-144Prime Medicine, Inc. (PRME)Grant/award (A): 45,000 (derivative) @ $0EDGAR
2024-06-104Rapport Therapeutics, Inc. (RAPP)
jointly with ARCH Venture Partners XII, LLC, ARCH Venture Partners XII, L.P., ARCH Venture Fund XII, L.P., CRANDELL KEITH, Burow Kristina, GILLIS STEVEN
Conversion (C): 3,728,738 @ $0 · Conversion (C): 20,000,000 (derivative) @ $0 · Conversion (C): 11,924,138 (derivative) @ $0EDGAR
2024-06-074Sana Biotechnology, Inc. (SANA)Grant/award (A): 54,278 (derivative) @ $0EDGAR
2024-06-034Vir Biotechnology, Inc. (VIR)Grant/award (A): 8,000 @ $0 · Grant/award (A): 16,000 (derivative) @ $0EDGAR
2024-04-044Boundless Bio, Inc. (BOLD)
jointly with CRANDELL KEITH, BYBEE CLINTON, GILLIS STEVEN
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 moreEDGAR
2024-02-204Prime Medicine, Inc. (PRME)Purchase (P): 3,200,000 @ $6.25EDGAR
2024-02-124Sana Biotechnology, Inc. (SANA)Purchase (P): 363,637 @ $5.50 · Purchase (P): 727,272 @ $5.50 · Purchase (P): 727,272 @ $5.50EDGAR

FilingPulse's Form 4 archive currently extends back to 2024-01-11 and is expanding backward through EDGAR history — earlier filings by this insider may not be indexed yet. Names and roles are shown as filed.

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