Is this Korro Bio (KRRO) Form 4 related to a sale or a grant of shares?

The Form 4 reflects an acquisition of shares tied to an RSU grant at a price of $0.00 per share , rather than a sale of existing shares.

Korro Bio (KRRO) awards chief scientific officer 21,715 RSUs

Q: How many shares did the Korro Bio (KRRO) chief scientific officer receive and how are they structured?

The officer received 21,715 shares of common stock , which are issuable upon settlement of a restricted stock unit (RSU) grant under the company’s 2023 Stock Option and Incentive Plan.

Q: What is the vesting schedule for the 21,715 RSUs reported by Korro Bio (KRRO)?

The RSUs will vest in two equal tranches: 50% on June 15, 2026 and 50% on December 15, 2026 , if the officer maintains a continuous Service Relationship through each date.

Q: What plan governs the RSU grant disclosed by Korro Bio (KRRO)?

The award was granted under the issuer’s 2023 Stock Option and Incentive Plan , referred to as the 2023 Plan in the disclosure.

Filing Impact

(Neutral)

Filing Sentiment

(Neutral)

Form Type

Rhea-AI Filing Summary

Korro Bio's Chief Scientific Officer received a grant of 21,715 shares of common stock on December 15, 2025, reported as an acquisition at a price of $0.00 per share. Following this transaction, the officer beneficially owns 21,715 shares directly.

The shares are issuable upon settlement of a restricted stock unit (RSU) award granted under the company’s 2023 Stock Option and Incentive Plan. The RSUs will vest in two equal installments: 50% on June 15, 2026 and 50% on December 15, 2026, provided the officer maintains a continuous Service Relationship through each vesting date.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Vincent Loic A

Role Chief Scientific Officer

Type	Security	Shares	Price	Value
Grant/Award	Common Stock	21,715	$0.00	--

Holdings After Transaction: Common Stock — 21,715 shares (Direct)

Footnotes (1)

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Form 4 Insider Transactions: What Each Field Means →

12/16/2025 - 04:09 PM

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^*

Vincent Loic A

(Last)

(First)

(Middle)

C/O KORRO BIO, INC.

60 FIRST STREET, 2ND FLOOR, SUITE 250

(Street)

CAMBRIDGE

02141

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
Korro Bio, Inc. [ KRRO ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
12/15/2025

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock⁽¹⁾	12/15/2025		A		21,715	A	$0.00	21,715	D

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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

1. Represents shares of common stock issuable upon settlement of a restricted stock unit (RSU) granted under the Issuer's 2023 Stock Option and Incentive Plan (the 2023 Plan) that will vest as follows: 50% on June 15, 2026 and 50% on December 15, 2026, in each case subject to the reporting person maintaining a continuous Service Relationship (as defined in the 2023 Plan) through each such date.

	/s/ Jeffrey Cerio, Attorney-in-fact	12/16/2025
	** 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.

Source: View Original Filing on SEC EDGAR

FAQ

What insider transaction did Korro Bio (KRRO) report in this Form 4?

The filing reports that Korro Bio’s Chief Scientific Officer acquired 21,715 shares of common stock, shown at a price of $0.00 per share, in the form of a restricted stock unit award.

How many shares did the Korro Bio (KRRO) chief scientific officer receive and how are they structured?

The officer received 21,715 shares of common stock, which are issuable upon settlement of a restricted stock unit (RSU) grant under the company’s 2023 Stock Option and Incentive Plan.

What is the vesting schedule for the 21,715 RSUs reported by Korro Bio (KRRO)?

The RSUs will vest in two equal tranches: 50% on June 15, 2026 and 50% on December 15, 2026, if the officer maintains a continuous Service Relationship through each date.

What plan governs the RSU grant disclosed by Korro Bio (KRRO)?

The award was granted under the issuer’s 2023 Stock Option and Incentive Plan, referred to as the 2023 Plan in the disclosure.

What is the officer’s beneficial ownership after this Korro Bio (KRRO) transaction?

After the reported transaction, the Chief Scientific Officer beneficially owns 21,715 shares of common stock, held in direct ownership.