X0306 4 2022-02-08 0 0001786205 Arcellx, Inc. ACLX 0001598542 Carroll Jill C/O ARCELLX, INC. 25 WEST WATKINS MILL ROAD, SUITE A GAITHERSBURG MD 20878 1 0 0 0 Common Stock 2022-02-08 4 C 0 3400144 0.00 A 3400144 I See footnote Common Stock 2022-02-08 4 P 0 66667 15.00 A 3466811 I See footnote Common Stock 2022-02-08 4 C 0 433196 0.00 A 433196 I See footnote Common Stock 2022-02-08 4 P 0 1600000 15.00 A 2033196 I See footnote Series A Preferred Stock 2022-02-08 4 C 0 1550309 0.00 D Common Stock 1550309 0 I See footnote Series B-1 Preferred Stock 2022-02-08 4 C 0 666651 0.00 D Common Stock 666651 0 I See footnote Series B-2 Preferred Stock 2022-02-08 4 C 0 533389 0.00 D Common Stock 533389 0 I See footnote Series C Preferred Stock 2022-02-08 4 C 0 649795 0.00 D Common Stock 649795 0 I See footnote Series C Preferred Stock 2022-02-08 4 C 0 433196 0.00 D Common Stock 433196 0 I See footnote All shares of Series A Preferred Stock, par value $0.001 per share, Series B-1 Preferred Stock, par value $0.001 per share, Series B-2 Preferred Stock, par value $0.001 per share, and Series C Preferred Stock, par value $0.001 per share, of the Issuer automatically converted on a one-for-one basis to shares of the Issuer's common stock, par value $0.001 per share ("Common Stock") immediately prior to the closing of the Issuer's initial public offering of its Common Stock, and have no expiration date. Shares directly held by SR One Capital Fund I Aggregator, L.P. SR One Capital Partners I, LP serves as the general partner of SR One Capital Fund I Aggregator, LP and SR One Capital Management, LLC serves as the general partner of SR One Capital Partners I, LP. The Reporting Person, a member of the Issuer's board of directors, is a partner of SR One Capital Management, LP, an entity affiliated with SR One Capital Fund I Aggregator, L.P. and, therefore, may be deemed to have a pecuniary interest over these shares. The Reporting Person disclaims beneficial ownership of the shares held of record by SR One Capital Fund I Aggregator, L.P. except to the extent of her pecuniary interest therein. SR One Capital Fund I Aggregator, LP purchased 66,667 shares of Common Stock of the Issuer in connection with the Issuer's public offering. Shares directly held by by SR One Co-Invest II, LLC. SR One Co-Invest Manager II, LLC serves as the manager of SR Co-Invest II, LLC, and SR One Capital Management, LLC serves as the managing member of SR Co-Invest Manager II, LLC. The Reporting Person, a member of the Issuer's board of directors, is a partner of SR One Capital Management, LP, an entity affiliated with SR One Co-Invest II, LLC and, therefore, may be deemed to have a pecuniary interest over these shares. The Reporting person disclaims beneficial ownership of the shares held of record by SR One Co-Invest II, LLC except to the extent of her pecuniary interest therein. SR One Co-Invest II, LLC purchased 1,600,000 shares of Common Stock of the Issuer in connection with the Issuer's public offering. /s/ Lance Thibault, as Attorney-in-Fact 2022-02-09