ARCH Venture Partners X, LLC - 01 Aug 2025 Form 4 Insider Report for Prime Medicine, Inc. (PRME)

Role
10%+ Owner
Signature
/s/ ARCH Venture Fund X, L.P., By: ARCH Venture Partners X, L.P., its General Partner, By: ARCH Venture Partners X, LLC, its General Partner, By: Mark McDonnell, attorney-in-fact
Issuer symbol
PRME
Transactions as of
01 Aug 2025
Net transactions value
+$9,999,990
Form type
4
Filing time
01 Aug 2025, 19:18:42 UTC
Previous filing
30 Jan 2025
Next filing
29 Oct 2025

Reporting Owners (8)

Name Relationship Address Signature Signature date CIK
ARCH Venture Partners X, LLC 10%+ Owner 8755 W. HIGGINS ROAD, SUITE 1025, CHICAGO /s/ ARCH Venture Fund X, L.P., By: ARCH Venture Partners X, L.P., its General Partner, By: ARCH Venture Partners X, LLC, its General Partner, By: Mark McDonnell, attorney-in-fact 01 Aug 2025 0001769012
ARCH Venture Partners X, L.P. 10%+ Owner 8755 W. HIGGINS ROAD, SUITE 1025, CHICAGO /s/ ARCH Venture Fund X Overage, L.P., By: ARCH Venture Partners X Overage, L.P., its General Partner, By: ARCH Venture Partners X, LLC, its General Partner, By: Mark McDonnell, attorney-in-fact 01 Aug 2025 0001782583
ARCH Venture Partners X Overage, L.P. 10%+ Owner 8755 W. HIGGINS ROAD, SUITE 1025, CHICAGO /s/ ARCH Venture Partners X, L.P., By: ARCH Venture Partners X, LLC, its General Partner, By: Mark McDonnell, attorney-in-fact 01 Aug 2025 0001768905
ARCH Venture Fund X, L.P. 10%+ Owner 8755 W. HIGGINS ROAD, SUITE 1025, CHICAGO /s/ ARCH Venture Partners X Overage, L.P., By: ARCH Venture Partners X, LLC, its General Partner, By: Mark McDonnell, attorney-in-fact 01 Aug 2025 0001757011
ARCH Venture Fund X Overage, L.P. 10%+ Owner 8755 W. HIGGINS ROAD, SUITE 1025, CHICAGO /s/ ARCH Venture Partners X, LLC, By: Mark McDonnell, attorney-in-fact 01 Aug 2025 0001757017
CRANDELL KEITH 10%+ Owner C/O ARCH VENTURE PARTNERS IX, LLC, 8755 W. HIGGINS ROAD, SUITE 1025, CHICAGO /s/ Keith Crandell, By: Mark McDonnell, attorney-in-fact 01 Aug 2025 0001219039
Burow Kristina 10%+ Owner 8755 W. HIGGINS ROAD,SUITE 1025, CHICAGO /s/ Kristina Burow, By: Mark McDonnell, attorney-in-fact 01 Aug 2025 0001569248
GILLIS STEVEN 10%+ Owner C/O ARCH VENTURE PARTNERS, 8755 WEST HIGGINS ROAD, SUITE 1025, CHICAGO /s/ Steven Gillis, By: Mark McDonnell, attorney-in-fact 01 Aug 2025 0001229592

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction PRME Common Stock Purchase $9,999,990 +3,030,300 +95% $3.30 6,230,300 01 Aug 2025 By ARCH Venture Fund XII, L.P. F4
holding PRME Common Stock 6,128,297 01 Aug 2025 By ARCH Venture Fund X, L.P. F1, F3
holding PRME Common Stock 6,128,297 01 Aug 2025 By ARCH Venture Fund X Overage, L.P. F2, F3
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Represents shares held directly by ARCH Venture Fund X, L.P. ("ARCH X"). ARCH Venture Partners X, L.P. ("AVP X LP") is the sole general partner of ARCH X.
F2 Represents shares held directly by ARCH Venture Fund X Overage, L.P. ("ARCH X Overage"). ARCH Venture Partners X Overage, L.P. ("AVP X Overage LP") is the sole general partner of ARCH X Overage.
F3 ARCH Venture Partners X, LLC ("AVP X LLC") is the sole general partner of each of AVP X LP and AVP X Overage LP. Keith Crandell, Kristina Burow and Steven Gillis are members of the investment committee of AVP X LLC (the "AVP X Committee Members"). AVP X LP and AVP X Overage LP may be deemed to beneficially own the shares held by ARCH X and ARCH X Overage, respectively, AVP X LLC may be deemed to beneficially own the shares held by ARCH X and ARCH X Overage, and each of the AVP X Committee Members may be deemed to share the power to direct the disposition and vote of the shares held by ARCH X and ARCH X Overage. AVP X LP, AVP X Overage LP, AVP X LLC, and the AVP X Committee Members each disclaim beneficial ownership except to the extent of any pecuniary interest therein, and this report shall not be deemed an admission that such shares are beneficially owned by them for Section 16 or any other purpose.
F4 Represents shares held directly by ARCH Venture Fund XII, L.P. ("ARCH XII"). ARCH Venture Partners XII, L.P. ("AVP XII LP") is the general partner of ARCH XII. ARCH Venture Partners XII, LLC ("AVP XII LLC") is the general partner of AVP XII LP. Keith Crandell, Kristina Burow and Steven Gillis are members of the investment committee of AVP XII LLC (the "AVP XII LLC Committee Members"). Each of AVP XII LP and AVP XII LLC may be deemed to beneficially own the shares held by ARCH XII, and each of the AVP XII LLC Committee Members may be deemed to share the power to direct the disposition and vote of the shares held by ARCH XII. Each of AVP XII LP, AVP XII LLC and the AVP XII LLC Committee Members disclaims beneficial ownership except to the extent of their pecuniary interest therein, if any.

Remarks:

This Form 4 is one of two reports relating to the same transaction being filed jointly by ARCH X, AVP X LP, ARCH X Overage, AVP X Overage LP, AVP X LLC, ARCH XII, AVP XII LP, AVP XII LLC, Keith Crandell, Kristina Burow and Steven Gillis (collectively, the "Reporting Persons"). Robert Nelsen has direct ownership of Common Stock and is filing his own Form 4 separately.