ARCH Venture Fund XII, L.P. - 07 Aug 2025 SCHEDULE 13D/A Report for Prime Medicine, Inc. Common Stock, $0.00001 par value (PRME)

Filing manager
ARCH Venture Fund XII, L.P.
Reporting owner
Robert Nelsen
Security
Prime Medicine, Inc. Common Stock, $0.00001 par value
Beneficially owned shares
18,587,036 shares
Ownership signal CIK-linked ownership evidence from parsed SEC filings. 2 signals
Large-stake signal

Form

SCHEDULE 13D/A

Active or control-oriented beneficial ownership filing.

Ownership

10%

Beneficial ownership of this reported class.

Shares

18,587,036 shares

Shares beneficially owned as disclosed.

Event date

07 Aug 2025

Date tied to the ownership event or amendment.

Accepted by SEC

11 Aug 2025

EDGAR acceptance date.

How to read this large-stake filing
  • Schedule 13D/G filings focus on beneficial ownership stakes, not a full portfolio.
  • Compare this filing with the holder history and issuer page before treating the percentage as a current position.
  • Use amendments to understand whether the disclosed stake increased, decreased, or changed reporting status.
Class ownership
10%
Subject security Names, identifiers, and filing context for this profile. 2 source fields
Symbol
PRME
Shares outstanding
178,721,500 shares
Source evidence Original filing metadata and source links for verification. 4 source fields
SEC form
SCHEDULE 13D/A
Accepted by SEC
11 Aug 2025, 21:48:39 UTC
Event date
07 Aug 2025
Source filing
View source filing

Key filing fact

ARCH Venture Fund XII, L.P. disclosed 10% ownership in Prime Medicine, Inc. Common Stock, $0.00001 par value (PRME) on 07 Aug 2025.

Key facts

  • ARCH Venture Fund XII, L.P. filed SCHEDULE 13D/A for Prime Medicine, Inc. Common Stock, $0.00001 par value (PRME).
  • Disclosed ownership: 10%.
  • Date of event: 07 Aug 2025.

Change

  • No earlier schedule filing is available for direct comparison.
  • Current filing was accepted on 11 Aug 2025, 21:48.

Research use

  • This page turns one Schedule 13D/G filing into a quick large-stake read before the raw reporting-person rows.
  • Use the linked SEC filing as the source of truth for ownership percentages, shares, and reporting-party details.

Evidence

Backed by Schedule 13D/13G

Beneficial ownership values are sourced from the original SEC Schedule 13D/13G filing.

View source filing

Reporting persons

Disclosed reporting parties (12)

Names, ownership percentages, voting power, signatures, titles, and CIKs as disclosed in this Schedule 13D/G filing.

Name Ownership Shares owned Sole voting power Shared voting power Signature Title CIK
ARCH Venture Fund X, L.P. 10% 18,486,894 0 18,486,894 ARCH Venture Partners X, L.P. its General Partner 0001757011
ARCH Venture Fund X Overage, L.P. 10% 18,486,894 0 18,486,894 ARCH Venture Partners X Overage, L.P. its General Partner 0001757017
ARCH Venture Fund XII, L.P. 10% 18,486,894 0 18,486,894 ARCH Venture Partners XII, L.P. its General Partner 0001906837
ARCH Venture Partners X, L.P. 10% 18,486,894 0 18,486,894 ARCH Venture Partners X, LLC its General Partner 0001782583
ARCH Venture Partners X Overage, L.P. 10% 18,486,894 0 18,486,894 ARCH Venture Partners X, LLC its General Partner 0001768905
ARCH Venture Partners XII, L.P. 10% 18,486,894 0 18,486,894 ARCH Venture Partners XII, LLC its General Partner 0001979765
ARCH Venture Partners X, LLC 10% 18,486,894 0 18,486,894 /s/ Mark McDonnell Mark McDonnell, as Attorney-in-Fact for Robert Nelsen, Managing Director 0001769012
ARCH Venture Partners XII, LLC 10% 18,486,894 0 18,486,894 /s/ Mark McDonnell Mark McDonnell, as Attorney-in-Fact for Keith Crandell, Managing Director 0001979548
Robert Nelsen 10% 18,587,036 100,142 18,486,894 /s/ Mark McDonnell Mark McDonnell, as Attorney-in-Fact for Robert Nelsen 0001219042
Keith Crandell 10% 18,486,894 0 18,486,894 /s/ Mark McDonnell Mark McDonnell, as Attorney-in-Fact for Keith Crandell 0001219039
Kristina Burow 10% 18,486,894 0 18,486,894 /s/ Mark McDonnell Mark McDonnell, as Attorney-in-Fact for Kristina Burow 0001569248
Steven Gillis 10% 18,486,894 0 18,486,894 /s/ Mark McDonnell Mark McDonnell, as Attorney-in-Fact for Steven Gillis 0001229592
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