Prime Medicine (PRME) CTO receives 375,000-share stock option grant tied to service

Rhea-AI Filing Summary

LEE ANN L. reported acquisition or exercise transactions in this Form 4 filing.

Prime Medicine, Inc. reported that Chief Technical Officer Lee Ann L. received a grant of stock options covering 375,000 shares of common stock. According to the terms, 1/48th of the option vests in substantially equal monthly installments starting on February 23, 2026, subject to her continued service, aligning this award with long-term employment and company performance.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider LEE ANN L.

Role Chief Technical Officer

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy)	375,000	$0.00	--

Holdings After Transaction: Stock Option (right to buy) — 375,000 shares (Direct)

Footnotes (1)

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Form 4 Insider Transactions: What Each Field Means →

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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)
02/23/2026

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)	$3.34	02/23/2026		A		375,000		(1)	02/23/2036	Common Stock	375,000	$0	375,000	D

Explanation of Responses:

1. 1/48th of the shares underlying this option vest and become exercisable in substantially equal monthly installments on each monthly anniversary of February 23, 2026, subject to the Reporting Person's continued service on each such vesting date.

Remarks:

	/s/ Ryan Brown, attorney-in-fact	02/24/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transaction did Prime Medicine (PRME) report for Lee Ann L.?

Prime Medicine reported a stock option grant to Chief Technical Officer Lee Ann L. for 375,000 shares. This is a compensation-related award, not an open-market purchase or sale, and is structured to vest over time based on continued service.

How many stock options did the Prime Medicine (PRME) CTO receive?

The Chief Technical Officer of Prime Medicine received a stock option covering 375,000 shares of common stock. This entire amount is reported as directly owned following the grant, subject to the vesting schedule described in the Form 4 footnote.

What is the vesting schedule for the PRME CTO’s 375,000 stock options?

The option vests in 1/48th installments each month starting on February 23, 2026. Vesting occurs on each monthly anniversary of that date, provided the reporting person continues serving the company on each relevant vesting date.

Is the Prime Medicine (PRME) Form 4 transaction a buy or sell of shares?

The Form 4 shows an acquisition of derivative securities through a stock option grant, not a market buy or sell. It is coded as a grant or award, reflecting equity-based compensation rather than trading activity in Prime Medicine’s common stock.

Does the PRME CTO’s option grant require continued service to vest?

Yes. The Form 4 states vesting is subject to the Reporting Person’s continued service on each applicable vesting date. If service ends, unvested portions of the 375,000-share option may not become exercisable under the stated terms.