ARCH Venture Partners XII, LLC

Director · Ten-percent owner · SPTX, MTSR, NMRA, PRME

As of 2026-09-16, ARCH Venture Partners XII, LLC has 113 Form 4 transactions on record across 4 companies — 40 in the trailing 12 months.

Everything this person has disclosed to the SEC on Form 4 — across every company they file for — reconstructed from the public record. A filing history, not a tip sheet.

Reconstructed holdings

Direct: $0Indirect: $138.4M$138.4Mas of 2026-09-16
  • Direct $0
  • Indirect $138.4M
SPTXindirect5,194,951 sh$115.0M
PRMEindirect6,230,300 sh$18.7M
NMRAindirect6,046,907 sh$4.7M

Reconstructed from this person's own Form 4 filings — the total each filing reported owning afterward, priced at the close on the as-of date shown. A filed position can lag the real one.

Direct and indirect holdings (e.g. through a trust or fund) are tagged separately, as filed.

Trades by company

MTSR · 92 trades
2025-11-13: Disposition, 8,313,680 sh2025-11-13: Disposition, 8,313,680 sh2025-11-13: Disposition, 18,503,128 sh2025-11-13: Disposition, 8,313,680 sh2025-11-13: Disposition, 18,503,128 sh2025-11-13: Disposition, 8,313,680 sh2025-11-13: Disposition, 18,503,128 sh2025-11-13: Disposition, 8,313,680 sh2025-11-13: Disposition, 18,503,128 sh2025-11-13: Disposition, 8,313,680 sh2025-11-13: Disposition, 18,503,128 sh2025-11-13: Disposition, 8,313,680 sh2025-11-13: Disposition, 8,313,680 sh2025-11-13: Disposition, 18,503,128 sh2025-11-13: Disposition, 8,313,680 sh2025-11-13: Disposition, 18,503,128 sh2025-11-13: Disposition, 18,503,128 sh2025-11-13: Disposition, 8,313,680 sh2025-11-13: Disposition, 18,503,128 sh2025-11-13: Disposition, 18,503,128 sh2025-02-03: Purchase, 1,432,224 sh ($25.8M)2025-02-03: Purchase, 789,998 sh ($14.2M)2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 19,933,333 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 16,006,949 sh2025-02-03: Conversion, 7,523,682 sh2025-02-03: Conversion, 19,933,333 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 16,006,949 sh2025-02-03: Conversion, 7,523,682 sh2025-02-03: Conversion, 19,933,333 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 16,006,949 sh2025-02-03: Conversion, 7,523,682 sh2025-02-03: Conversion, 19,933,333 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 16,006,949 sh2025-02-03: Conversion, 7,523,682 sh2025-02-03: Conversion, 19,933,333 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 7,523,682 sh2025-02-03: Conversion, 19,933,333 sh2025-02-03: Conversion, 16,006,949 sh2025-02-03: Conversion, 19,933,333 sh2025-02-03: Conversion, 16,006,949 sh2025-02-03: Conversion, 7,523,682 sh2025-02-03: Conversion, 19,933,333 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 16,006,949 sh2025-02-03: Conversion, 7,523,682 sh2025-02-03: Conversion, 19,933,333 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 16,006,949 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 7,523,682 sh2025-02-03: Conversion, 16,006,949 sh2025-02-03: Conversion, 7,523,682 sh2025-02-03: Conversion, 16,006,949 sh2025-02-03: Conversion, 7,523,682 sh2025-02-03: Conversion, 19,933,333 sh2025-02-03: Conversion, 15,000,000 sh2025-02-03: Conversion, 2,678,571 sh2025-02-03: Conversion, 15,000,000 sh
SPTX · 19 trades
2026-05-04: Purchase, 1,100,000 sh ($19.8M)2026-05-04: Conversion, 2,513,686 sh ($0)2026-05-04: Conversion, 2,681,265 sh ($0)2026-05-04: Conversion, 2,681,265 sh2026-05-04: Conversion, 2,513,686 sh2026-05-04: Conversion, 2,681,265 sh2026-05-04: Conversion, 2,513,686 sh2026-05-04: Conversion, 2,681,265 sh2026-05-04: Conversion, 2,513,686 sh2026-05-04: Conversion, 2,681,265 sh2026-05-04: Conversion, 2,513,686 sh2026-05-04: Conversion, 2,681,265 sh2026-05-04: Conversion, 2,513,686 sh2026-05-04: Conversion, 2,681,265 sh2026-05-04: Conversion, 2,513,686 sh2026-05-04: Conversion, 2,513,686 sh2026-05-04: Conversion, 2,681,265 sh2026-05-04: Conversion, 2,513,686 sh2026-05-04: Conversion, 2,681,265 sh
NMRA · 1 trade
2025-10-27: Purchase, 1,915,700 sh ($5.0M)
PRME · 1 trade
2025-08-01: Purchase, 3,030,300 sh ($10.0M)

Filing ledger

DateCompanyActionShares @ priceValueOwnership ΔOwned afterFiling
2026-05-04SPTXPurchase1,100,000 @ $18.00$19.8M+21.2% of holding6,294,951Form 4
2025-10-27NMRAPurchase1,915,700 @ $2.61$5.0M+46.4% of holding6,046,907Form 4
2025-08-01PRMEPurchase3,030,300 @ $3.30$10.0M+94.7% of holding6,230,300Form 4
2025-02-03MTSRPurchase1,432,224 @ $18.00$25.8M+8.4% of holding18,503,128Form 4
2025-02-03MTSRPurchase789,998 @ $18.00$14.2M+10.5% of holding8,313,680Form 4
108 award / exercise / gift records — not counted as purchases
DateCompanyActionSharesOwned afterFiling
2026-05-04SPTXConversion2,513,6860Form 4
2026-05-04SPTXConversion2,681,2650Form 4
2026-05-04SPTXConversion2,681,2655,194,951Form 4
2026-05-04SPTXConversion2,513,6862,513,686Form 4
2026-05-04SPTXConversion2,681,2655,194,951Form 4
2026-05-04SPTXConversion2,513,6862,513,686Form 4
2026-05-04SPTXConversion2,681,2655,194,951Form 4
2026-05-04SPTXConversion2,513,6862,513,686Form 4
2026-05-04SPTXConversion2,681,2655,194,951Form 4
2026-05-04SPTXConversion2,513,6862,513,686Form 4
2026-05-04SPTXConversion2,681,2655,194,951Form 4
2026-05-04SPTXConversion2,513,6862,513,686Form 4
2026-05-04SPTXConversion2,681,2655,194,951Form 4
2026-05-04SPTXConversion2,513,6862,513,686Form 4
2026-05-04SPTXConversion2,513,6862,513,686Form 4
2026-05-04SPTXConversion2,681,2655,194,951Form 4
2026-05-04SPTXConversion2,513,6862,513,686Form 4
2026-05-04SPTXConversion2,681,2655,194,951Form 4
2025-11-13MTSRDisposition8,313,6800Form 4
2025-11-13MTSRDisposition8,313,6800Form 4
2025-11-13MTSRDisposition18,503,1280Form 4
2025-11-13MTSRDisposition8,313,6800Form 4
2025-11-13MTSRDisposition18,503,1280Form 4
2025-11-13MTSRDisposition8,313,6800Form 4
2025-11-13MTSRDisposition18,503,1280Form 4
2025-11-13MTSRDisposition8,313,6800Form 4
2025-11-13MTSRDisposition18,503,1280Form 4
2025-11-13MTSRDisposition8,313,6800Form 4
2025-11-13MTSRDisposition18,503,1280Form 4
2025-11-13MTSRDisposition8,313,6800Form 4
2025-11-13MTSRDisposition8,313,6800Form 4
2025-11-13MTSRDisposition18,503,1280Form 4
2025-11-13MTSRDisposition8,313,6800Form 4
2025-11-13MTSRDisposition18,503,1280Form 4
2025-11-13MTSRDisposition18,503,1280Form 4
2025-11-13MTSRDisposition8,313,6800Form 4
2025-11-13MTSRDisposition18,503,1280Form 4
2025-11-13MTSRDisposition18,503,1280Form 4
2025-02-03MTSRConversion2,678,5710Form 4
2025-02-03MTSRConversion19,933,3330Form 4

Source: SEC Form 4 filings. Each row links to its original filing.

Research tool, not investment advice — historical frequencies, not recommendations. A product of Marovel Technologies LLC. Full terms.