X0609 4 2026-06-10 0001787400 Nkarta, Inc. NKTX 0001346824 RA CAPITAL MANAGEMENT, L.P. false 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 true false true false 0001315082 RA Capital Healthcare Fund LP false 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 1 0 0001780117 RA Capital Nexus Fund, L.P. false 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 0 0 0001384859 Kolchinsky Peter false C/O RA CAPITAL MANAGEMENT, L.P. 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 1 0 0001619841 Shah Rajeev M. false RA CAPITAL MANAGEMENT, L.P. 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 1 0 0 Stock Option (right to buy) 2.46 2026-06-10 4 A 0 37000 0 A 2036-06-09 Common Stock 37000 37000 I See Footnotes All shares subject to the option vest 100% on the first to occur of (i) June 10, 2027 or (ii) the day immediately preceding the first annual meeting of the Issuer's stockholders to occur after the date of grant of the award, subject to Dr. Scheiner's continued service through the applicable vesting date. Each grant, to the extent outstanding and otherwise unvested, will become fully vested should a "change in control" of the Issuer occur (as described in the applicable award agreement) or upon the Dr. Scheiner's separation from service with the Issuer due to the his death or "disability" (as described in the applicable award agreement). RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund") and RA Capital Nexus Fund, L.P. (the "Nexus Fund"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. Each of the Adviser, the Adviser GP, the Fund, the Nexus Fund, Dr. Kolchinsky and Mr. Shah disclaims beneficial ownership of any of the reported securities, except to the extent of its or his respective pecuniary interest therein. Under Dr. Scheiner's arrangement with the Adviser, Dr. Scheiner holds the option for the benefit of the Fund and the Nexus Fund. Dr. Scheiner is obligated to turn over to the Adviser any net cash or stock received upon exercise of the option, which will offset advisory fees owed by the Fund and the Nexus Fund to the Adviser. The Reporting Persons therefore disclaim beneficial ownership of the option and underlying common stock. Dr. Zachary Scheiner, a Principal of the Adviser, serves on the Issuer's board of directors. /s/ Peter Kolchinsky, Manager of RA Capital Management, L.P. 2026-06-11 /s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC the General Partner of RA Capital Healthcare Fund, L.P. 2026-06-11 /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund GP, LLC the General Partner of RA Capital Nexus Fund, L.P. 2026-06-11 /s/ Peter Kolchinsky, individually 2026-06-11 /s/ Rajeev Shah, individually 2026-06-11