X0609 4 2026-06-22 0001703647 Korro Bio, Inc. KRRO 0001030575 FORMELA JEAN FRANCOIS false C/O KORRO BIO, INC. 60 FIRST STREET, 2ND FLOOR, SUITE 250 CAMBRIDGE MA 02141 true false false false 1 Common Stock 2026-06-22 4 S 0 3382 13.95 D 936252 I See footnote Common Stock 2026-06-22 4 S 0 580 13.95 D 194075 I See footnote Common Stock 2026-06-23 4 S 0 101579 14.25 D 834673 I See footnote Common Stock 2026-06-23 4 S 0 17426 14.25 D 176649 I See footnote Common Stock 2026-06-24 4 S 0 40679 14.60 D 793994 I See footnote Common Stock 2026-06-24 4 S 0 666 14.98 D 793328 I See footnote Common Stock 2026-06-24 4 S 0 6979 14.60 D 169670 I See footnote Common Stock 2026-06-24 4 S 0 114 14.98 D 169556 I See footnote Shares were sold pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on April 8, 2026. These shares are held directly by Atlas Venture Fund XI, L.P. ("Atlas XI"). Atlas Venture Associates XI, L.P. ("AVA XI LP") is the general partner of Atlas XI. Atlas Venture Associates XI, LLC ("AVA XI LLC") is the general partner of AVA XI LP. The Reporting Person is a member of AVA XI LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any. These shares are held directly by Atlas Venture Opportunity Fund II, L.P. ("AVOF II"). Atlas Venture Associates Opportunity II, L.P. ("AVAO II LP") is the general partner of AVOF II. Atlas Venture Associates Opportunity II, LLC ("AVAO II LLC") is the general partner of AVAO II LP. The Reporting Person is a member of AVAO II LLC and disclaims Section 16 beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $13.95 to $14.49 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold each separate price within the ranges set forth in footnotes (4), (5) and (6). The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $13.95 to $14.88 inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $14.97 to $15.10 inclusive. /s/ Ommer Chohan, Attorney-in-fact 2026-06-24