X0508 4 2026-02-02 0001703647 Korro Bio, Inc. KRRO 0001997920 Aiyar Ram C/O KORRO BIO, INC. 60 FIRST STREET, 2ND FLOOR, SUITE 250 CAMBRIDGE MA 02141 true true false false President and CEO false Common Stock 2026-02-02 4 A false 40000 0.00 A 40000 D Common Stock 4613 I Shares are held by The Ram Aiyar Irrevocable Trust. Stock Option (Right to Buy) 13.05 2026-02-02 4 A false 80000 0 A 2036-02-01 Common Stock 80000 80000 D 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. 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. 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. /s/ Jeffrey Cerio, Attorney-in-fact 2026-02-03