[Form 4] Prime Medicine, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Chief Technical Officer Ann L. Lee filed a Form 4 showing a one-time repricing of 361,990 stock options originally granted under Prime Medicine’s 2019 and 2022 equity plans. On 08-01-2025 shareholders approved lowering the exercise price of the affected options from $12.30 and $8.49 to $4.04, the closing share price on the repricing date.

• Each original grant (180,995 options expiring 03-31-2033 and 180,995 options expiring 02-21-2034) was cancelled (coded “D”) and immediately re-granted (coded “A”) at the new strike.
• No change in the total number of options or underlying common shares; ownership remains 361,990 options, direct.
• All other terms, including vesting schedules, remain unchanged.

The filing signals management’s desire to restore the retention and incentive value of underwater options after PRME’s share price decline. While it is cash-neutral and non-dilutive today, repricing can draw shareholder-rights scrutiny because it rewards executives for past price under-performance without imposing new performance hurdles.

Positive

• Repricing aligns management incentives with current market value by lowering strike to $4.04

Negative

• Exercise-price cut reflects 50-plus % share-price decline since original grants
• Resetting underwater options without new performance hurdles may be viewed as shareholder-unfriendly

Insights

Corporate Governance Analyst

TL;DR: Option repricing helps retention but raises fairness concerns.

This shareholder-approved repricing resets 362 k CTO options to $4.04, a 51-67 % cut vs. prior strikes. Although no new dilution occurs, investors often view such resets as a transfer of value from shareholders to insiders, especially absent additional performance conditions. It highlights PRME’s significant share-price deterioration since grants and could feature in proxy-advisory voting recommendations. Overall governance impact is modestly negative but not financially material.

Equity Research Analyst

TL;DR: Neutral earnings impact; signals management expects upside.

The repricing has no P&L effect this quarter aside from a potential small incremental non-cash compensation charge spread over the remaining vesting term. More importantly, management is betting that $4.04 is a floor; if PRME executes on its gene-editing pipeline, in-the-money options can re-align incentives with shareholder value creation. Given unchanged share count and negligible cash cost, equity valuation remains unaffected.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

LEE ANN L.

(Last) (First) (Middle)

C/O PRIME MEDICINE, INC.

60 FIRST STREET

(Street)

CAMBRIDGE MA 02141

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Prime Medicine, Inc. [ PRME ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Technical Officer

3. Date of Earliest Transaction (Month/Day/Year)
08/01/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	$12.3	08/01/2025		D(1)			180,995	(2)	03/31/2033	Common Stock	180,995	(1)	0	D
Stock Option (right to buy)	$4.04	08/01/2025		A(1)		180,995		(2)	03/31/2033	Common Stock	180,995	(1)	180,995	D
Stock Option (right to buy)	$8.49	08/01/2025		D(1)			180,995	(2)	02/21/2034	Common Stock	180,995	(1)	0	D
Stock Option (right to buy)	$4.04	08/01/2025		A(1)		180,995		(2)	02/21/2034	Common Stock	180,995	(1)	180,995	D

Explanation of Responses:

1. Effective as of August 1, 2025 (the "Repricing Date"), the Issuer's stockholders approved a one-time repricing of certain outstanding stock options (the "Repriced Options") granted under the Issuer's 2019 Stock Option and Grant Plan, as amended (the "2019 Plan") and/or the 2022 Stock Option and Incentive Plan (the "2022 Plan" and, together with the 2019 Plan, the "Plans"), which reduced the per share exercise price of each Repriced Option to $4.04, representing the closing price of the Issuer's common stock on The Nasdaq Global Market on the Repricing Date (the "Option Repricing"). Except as modified by the Option Repricing, all other terms and conditions of the Repriced Options, including, without limitation, any provisions with respect to vesting and term of the Repriced Options, remain in full force and effect.

2. This stock option award was issued pursuant to the 2019 Plan and/or the 2022 Plan, as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

Remarks:

	/s/ Ryan Brown, attorney-in-fact	08/05/2025
	** Signature of Reporting Person	Date
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