SCHEDULE 13G/A 0001104659-24-026668 0001346824 XXXXXXXX LIVE 1 Common Stock, par value $0.001 per share 12/31/2024 0001831915 CYTEK BIOSCIENCES, INC. 23285D109 47215 LAKEVIEW BOULEVARD FREMONT CA 94538 Rule 13d-1(d) RA Capital Management, L.P. DE 0.00 0.00 0.00 0.00 0.00 0.0 IA PN Peter Kolchinsky X1 0.00 0.00 0.00 0.00 0.00 0.0 HC IN Rajeev Shah X1 0.00 0.00 0.00 0.00 0.00 0.0 HC IN RA Capital Healthcare Fund, L.P. DE 0.00 0.00 0.00 0.00 0.00 0.0 PN CYTEK BIOSCIENCES, INC. 47215 LAKEVIEW BOULEVARD, FREMONT, CA, 94538. The names of the persons filing this report (collectively, the "Reporting Persons") are: RA Capital Management, L.P. ("RA Capital") Peter Kolchinsky Rajeev Shah RA Capital Healthcare Fund, L.P. (the "Fund") The Reporting Persons expressly disclaim status as a "group" for purposes of this Schedule 13G. The address of the principal business office of each of the Reporting Persons is: c/o RA Capital Management, L.P., 200 Berkeley Street, 18th Floor, Boston MA 02116 RA Capital and the Fund are Delaware limited partnerships. Dr. Kolchinsky and Mr. Shah are United States citizens. Y Row 9 of each Reporting Person's cover page to this Schedule 13G sets forth the aggregate number of securities of the Issuer beneficially owned by such Reporting Person as of December 31, 2024 and is incorporated by reference. Row 11 of each Reporting Person's cover page to this Schedule 13G sets forth the percentages of the securities of the Issuer beneficially owned by such Reporting Person as of December 31, 2024 and is incorporated by reference. Row 5 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of December 31, 2024 and is incorporated by reference. Row 6 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of December 31, 2024 and is incorporated by reference. Row 7 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of December 31, 2024 and is incorporated by reference. Row 8 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of December 31, 2024 and is incorporated by reference. N Y Y Y Y Y Y Exhibit 99.1 Joint Filing Agreement RA Capital Management, L.P. /s/ Peter Kolchinsky 02/14/2025 Peter Kolchinsky /s/ Peter Kolchinsky 02/14/2025 Rajeev Shah /s/ Rajeev Shah 02/14/2025 RA Capital Healthcare Fund, L.P. /s/ Peter Kolchinsky 02/14/2025