Alphabet Inc. — Director's Dealing 2023

May 18, 2023

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Prime Medicine, Inc. (PRME)
CIK: 0001894562
Period of Report: 2023-05-16

Reporting Person: GV 2019 GP, L.L.C. (10% Owner)
Reporting Person: GV 2019 GP, L.P. (10% Owner)
Reporting Person: GV 2019, L.P. (10% Owner)
Reporting Person: GV 2021 GP, L.L.C. (10% Owner)
Reporting Person: GV 2021 GP, L.P. (10% Owner)
Reporting Person: GV 2021, L.P. (10% Owner)
Reporting Person: Alphabet Inc. (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2023-05-16	Common Stock	S	50649	$12.5901	Disposed	10750324	Indirect
2023-05-17	Common Stock	S	15000	$12.7733	Disposed	10735324	Indirect

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	1762440	Indirect

Footnotes

F1: This transaction was entered into pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on April 6, 2023.

F2: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $12.465 to $12.69, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the U.S. Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote 2 and in footnote 4 of this Form 4.

F3: The securities reported in this row are directly beneficially owned by GV 2019, L.P. (the "2019 Partnership"). The general partner of the 2019 Partnership is GV 2019 GP, L.P. (the "2019 GP"). The general partner of the 2019 GP is GV 2019 GP, L.L.C. ("GV 2019 LLC"). The sole member of GV 2019 LLC is Alphabet Holdings LLC ("Alphabet Holdings"). The sole member of Alphabet Holdings is XXVI Holdings Inc. ("XXVI"). The controlling stockholder of XXVI is Alphabet Inc. Each of the 2019 GP, GV 2019 LLC, Alphabet Holdings, XXVI, and Alphabet Inc. may be deemed to indirectly beneficially own (as the term is defined in Rule 13d-3 of the Securities Exchange Act of 1934, as amended (the "Act")) the securities directly beneficially owned by the 2019 Partnership. Each of the aforementioned parties disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

F4: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $12.95 to $13.075, inclusive.

F5: The securities reported in this row are directly beneficially owned by GV 2021, L.P. (the "2021 Partnership"). The general partner of the 2021 Partnership is GV 2021 GP, L.P. (the "2021 GP"). The general partner of the 2021 GP is GV 2021 GP, L.L.C. ("GV 2021 LLC"). The sole member of GV 2021 LLC is Alphabet Holdings. The sole member of Alphabet Holdings is XXVI. The controlling stockholder of XXVI is Alphabet Inc. Each of the 2021 GP, GV 2021 LLC, Alphabet Holdings, XXVI, and Alphabet Inc. may be deemed to indirectly beneficially own (as the term is defined in Rule 13d-3 of the Act) the securities directly beneficially owned by the 2021 Partnership. Each of the aforementioned parties disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.