X0508 4 2024-02-08 0001770121 Sana Biotechnology, Inc. SANA 0001757011 ARCH Venture Fund X, L.P. 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001757017 ARCH Venture Fund X Overage, L.P. 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001666306 ARCH Venture Fund IX, L.P. 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001666307 ARCH Venture Fund IX Overage, L.P. 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001723173 ARCH Venture Partners IX, L.P. 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001723172 ARCH Venture Partners IX Overage, L.P. 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001782583 ARCH Venture Partners X, L.P. 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001768905 ARCH Venture Partners X Overage, L.P. 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001723174 ARCH Venture Partners IX, LLC 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001769012 ARCH Venture Partners X, LLC 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0 Common Stock 2024-02-08 4 P 0 363637 5.50 A 10667387 I See Footnote Common Stock 10301250 I See Footnote Common Stock 2024-02-08 4 P 0 727272 5.50 A 12446022 I See Footnote Common Stock 2024-02-08 4 P 0 727272 5.50 A 12446022 I See Footnote Represents shares held directly by ARCH Venture Fund IX, L.P. (ARCH IX). ARCH Venture Partners IX, L.P. (AVP IX LP) is the sole general partner of ARCH IX. Represents shares held directly by ARCH Venture Fund IX Overage, L.P. (ARCH IX Overage). ARCH Venture Partners IX Overage, L.P. (AVP IX Overage LP) is the sole general partner of ARCH IX Overage. ARCH Venture Partners IX, LLC (AVP IX LLC) is the sole general partner of each of AVP IX LP and AVP IX Overage LP. Keith Crandell and Clinton Bybee are managing directors of AVP IX LLC (the AVP IX MDs). AVP IX LP and AVP IX Overage LP may be deemed to beneficially own the shares held by ARCH IX and ARCH IX Overage, respectively, AVP IX LLC may be deemed to beneficially own the shares held by ARCH IX and ARCH IX Overage, and each of the AVP IX MDs may be deemed to share the power to direct the disposition and vote of the shares held by ARCH IX and ARCH IX Overage. AVP IX LP, AVP IX Overage LP, AVP IX LLC, and the AVP IX MDs each disclaim beneficial ownership except to to the extent of any pecuniary interest therein. Represents shares held directly by ARCH Venture Fund X, L.P. (ARCH X). ARCH Venture Partners X, L.P. (AVP X LP) is the sole general partner of ARCH X. Represents shares held directly by ARCH Venture Fund X Overage, L.P. (ARCH X Overage). ARCH Venture Partners X Overage, L.P. (AVP X Overage LP) is the sole general partner of ARCH X Overage. ARCH Venture Partners X, LLC (AVP X LLC) is the sole general partner of each of AVP X LP and AVP X Overage LP. Keith Crandell, Kristina Burow and Steven Gillis are members of the investment committee of AVP X LLC (the AVP X Committee Members). AVP X LP and AVP X Overage LP may be deemed to beneficially own the shares held by ARCH X and ARCH X Overage, respectively, AVP X LLC may be deemed to beneficially own the shares held by ARCH X and ARCH X Overage, and each of the AVP X Committee Members may be deemed to share the power to direct the disposition and vote of the shares held by ARCH X and ARCH X Overage. AVP X LP, AVP X Overage LP, AVP X LLC, and the AVP X Committee Members each disclaim beneficial ownership except to the extent of any pecuniary interest therein. This Form 4 is one of two reports relating to the same transaction being filed jointly by ARCH IX, AVP IX LP, ARCH IX Overage, AVP IX Overage LP, AVP IX LLC, ARCH X, AVP X LP, ARCH X Overage, AVP X Overage LP, AVP X LLC, Keith Crandell, Clinton Bybee, Kristina Burow and Steven Gillis (collectively, the "Reporting Persons"). Robert Nelsen has direct ownership of Common Stock and is filing his own Form 4 separately. /s/ ARCH Venture Fund X, L.P., By: ARCH Venture Partners X, L.P., its General Partner, By: ARCH Venture Partners X, LLC, its General Partner, By: Mark McDonnell,: attorney in-fact 2024-02-12 /s/ ARCH Venture Fund X Overage, L.P., By: ARCH Venture Partners X Overage, L.P., its General Partner, By: ARCH Venture Partners X, LLC, its General Partner, By: Mark McDonnell, attorney in-fact 2024-02-12 /s/ ARCH Venture Fund IX, L.P., By: ARCH Venture Partners IX, L.P., its General Partner, By: ARCH Venture Partners IX, LLC, its General Partner, By: Mark McDonnell, attorney in-fact 2024-02-12 /s/ ARCH Venture Fund IX Overage, L.P., By: ARCH Venture Partners IX Overage, L.P., its General Partner, By: ARCH Venture Partners IX, LLC, its General Partner, By: Mark McDonnell, attorney in-fact 2024-02-12 /s/ ARCH Venture Partners X, L.P., its General Partner, By: ARCH Venture Partners X, LLC, its General Partner, By: Mark McDonnell, attorney in-fact 2024-02-12 /s/ ARCH Venture Partners X Overage, L.P., its General Partner, By: ARCH Venture Partners X, LLC, its General Partner, By: Mark McDonnell, attorney in-fact 2024-02-12 /s/ ARCH Venture Partners X, LLC, its General Partner, By: Mark McDonnell, attorney in-fact 2024-02-12 /s/ ARCH Venture Partners IX, L.P., its General Partner, By: ARCH Venture Partners IX, LLC, its General Partner, By: Mark McDonnell, attorney in-fact 2024-02-12 /s/ ARCH Venture Partners IX Overage, L.P., its General Partner, By: ARCH Venture Partners IX, LLC, its General Partner, By: Mark McDonnell, attorney in-fact 2024-02-12 /s/ ARCH Venture Partners IX, LLC, its General Partner, By: Mark McDonnell, attorney in-fact 2024-02-12