X0306 4 2020-10-14 0 0001741830 Kronos Bio, Inc. KRON 0001296549 Belldegrun Arie C/O KRONOS BIO, INC. 1300 SO. EL CAMINO REAL, SUITE 300 SAN MATEO CA 94402 1 0 0 0 Common Stock 2020-10-14 4 C 0 182866 A 438703 I By Bellco Legacy II Trust Common Stock 2020-10-14 4 C 0 240872 A 679575 I By Bellco Legacy II Trust Common Stock 2020-10-14 4 C 0 685750 A 685750 I By Vida Ventures, LLC Common Stock 2020-10-14 4 C 0 1376313 A 2062063 I By Vida Ventures, LLC Common Stock 2020-10-14 4 C 0 253251 16.15 A 2315314 I By Vida Ventures, LLC Series Seed Preferred Stock 2020-10-14 4 C 0 173333 D Common Stock 182866 0 I By Bellco Legacy II Trust Series A Preferred Stock 2020-10-14 4 C 0 228315 D Common Stock 240872 0 I By Bellco Legacy II Trust Series Seed Preferred Stock 2020-10-14 4 C 0 650000 D Common Stock 685750 0 I By Vida Ventures, LLC Series A Preferred Stock 2020-10-14 4 C 0 1304563 D Common Stock 1376313 0 I By Vida Ventures, LLC Convertible Promissory Note 16.15 2020-10-14 4 C 0 4090015.57 0.00 D 2022-02-20 Common Stock 253251 0 I By Vida Ventures, LLC Each share of Series Seed Preferred Stock and Series A Preferred Stock (the "Preferred Stock") automatically converted into 1.055 shares of Common Stock upon the closing of the Issuer's initial public offering. The Preferred Stock had no expiration date. The reporting person currently serves as the trustee of Bellco Legacy II Trust ("Bellco"). His wife, Dr. Rebecka Belldegrun, is the beneficiary of Bellco. VV Manager LLC is the manager of Vida Ventures, LLC ("Vida"). The Reporting Person is a Senior Managing Director of VV Manager LLC and may therefore be deemed to be the beneficial owner of the securities held by Vida. The convertible promissory note automatically converted into shares of the Issuer's common stock upon the closing of the Issuer's initial public offering. /s/ David Tanen, Attorney-in-Fact 2020-10-16