Ram Aiyar - 02 Feb 2026 Form 4 Insider Report for Korro Bio, Inc. (KRRO)

Role: President and CEO, Director
Signature: /s/ Jeffrey Cerio, Attorney-in-fact
Issuer symbol: KRRO
Transactions as of: 02 Feb 2026
Net transactions value: $0
Form type: 4
Filing time: 03 Feb 2026, 16:17:03 UTC
Previous filing: 05 Feb 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Aiyar Ram	President and CEO, Director	C/O KORRO BIO, INC., 60 FIRST STREET, 2ND FLOOR, SUITE 250, CAMBRIDGE	/s/ Jeffrey Cerio, Attorney-in-fact	03 Feb 2026	0001997920

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	KRRO	Common Stock	Award	$0	+40,000		$0.000000	40,000	02 Feb 2026	Direct	F1
holding	KRRO	Common Stock						4,613	02 Feb 2026	Shares are held by The Ram Aiyar Irrevocable Trust.	F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	KRRO	Stock Option (Right to Buy)	Award	$0	+80,000		$0.000000	80,000	02 Feb 2026	Common Stock	80,000	$13.05	Direct	F3

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	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 August 3, 2026 and 50% on February 1, 2027, in each case subject to the Reporting Person's continued service on each such vesting date.
F2	Shares held by The Ram Aiyar Irrevocable Trust, for which the Reporting Person serves as trustee. The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose.
F3	The shares subject to the option vest in 48 equal monthly installments commencing from February 2, 2026, subject to the Reporting Person's continued service on each such vesting date.