X0306 4 2020-08-05 0 0001564406 Oak Street Health, Inc. ?OSH? 0001793397 COOK TIMOTHY M C/O OAK STREET HEALTH, INC. 30 W. MONROE STREET, SUITE 1200 CHICAGO IL 60603 0 1 0 0 Chief Financial Officer Common stock, $0.001 par value 2020-08-10 4 J 0 1508576 0.00 A 1508576 D Common stock, $0.001 par value 2020-08-10 4 A 0 48 0.00 A 1508624 D Common stock, $0.001 par value 2020-08-10 4 J 0 42241 0.00 A 42241 I Through Elizabeth Violet Cook Irrevocable Trust dtd 8/4/2020 Common stock, $0.001 par value 2020-08-10 4 J 0 42241 0.00 A 42241 I Through Connor Thomas Cook Irrevocable Trust dtd 8/4/2020 Employee Stock Options (Right to Buy) 21.00 2020-08-05 4 A 0 172150 0.00 A 2030-08-05 Common Stock, par value $0.001 172150 172150 D Employee Stock Options (Right to Buy) 21.00 2020-08-05 4 A 0 192576 0.00 A 2030-08-05 Common Stock, par value $0.001 192576 192576 D Employee Stock Options (Right to Buy) 21.00 2020-08-05 4 A 0 96784 0.00 A 2030-08-05 Common Stock, par value $0.001 96784 96784 D Employee Stock Options (Right to Buy) 21.00 2020-08-05 4 A 0 10212 0.00 A 2030-08-05 Common Stock, par value $0.001 10212 10212 I Through Connor Thomas Cook Irrevocable Trust dtd 8/4/2020 Employee Stock Options (Right to Buy) 21.00 2020-08-05 4 A 0 10212 0.00 A 2030-08-05 Common Stock, par value $0.001 10212 10212 I Through Elizabeth Violet Cook Irrevocable Trust dtd 8/4/2020 These shares of common stock of Oak Street Health, Inc. (the "Issuer") were issued in connection with the closing of the Issuer's initial public offering on August 10, 2020 (the "Closing Date") in exchange for incentive units pursuant to the transactions contemplated by the Master Structuring Agreement dated August 10, 2020, by and among the Issuer, OSH Merger Sub 1, LLC, Quantum Strategic Partners Ltd., General Atlantic OSH Interholdco L.P., OSH Management Holdings, LLC ("Management Holdings"), Oak Street Health, LLC and Geoffrey Price dated August 10, 2020 (the "Organizational Transactions"). Represents shares of the Issuer's common stock, par value $0.001 issued under the Oak Street Health Omnibus Incentive Plan (the "Plan") in exchange for unvested incentive units of Management Holdings in connection with the Organizational Transactions. The issuance of these securities was approved by the Issuer's board of directors under Rule 16b-3. Represents options issued under the Plan in exchange for unvested performance-vesting incentive units in Management Holdings in connection with the Organizational Transactions. These options will cliff vest 100% on August 10, 2023. Represents options issued under the Plan in exchange for unvested time-vesting incentive units in Management Holdings in connection with the Organizational Transactions. These options will vest 25% on August 20, 2020 and then in twelve equal quarterly installments beginning on November 20, 2020. Represents options issued under the Plan. Such options will cliff vest 100% on August 5, 2021. /s/ Robert Guenthner, as attorney-in-fact for Timothy Cook. 2020-08-12