X0306 4 2022-02-21 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 2022-02-21 4 A 0 69841 0.00 A 1358721 D Common Stock, $0.001 par value 42241 I Through Elizabeth Violet Cook Irrevocable Trust dtd 8//4/2020 Common Stock, $0.001 par value 42241 I Through Conner Thomas Cook Irrevocable Trust dtd 8/4/2020 Performance Stock Option (Right to Buy) 15.75 2022-02-21 4 A 0 281329 0.00 A 2032-02-21 Common Stock, par value $0.001 281329 281329 D Represents Restricted Stock Units issued to the Reporting Person under Oak Street Health, Inc.'s Omnibus Incentive Plan (the "Plan") which shall become due and payable in four equal annual installments on the anniversary date of the grant date, subject to the terms and conditions of the Plan. 50% of the shares issuable upon exercise of this Option shall vest on or after December 31, 2023 on the date that the Committee certifies the achievement of the Performance Metric for the First Performance Period and 50% of the shares issuable upon exercise of this Option shall vest on or after December 31, 2024 on the date that the Committee certifies the achievement of the Performance Metric for the Second Performance Period. The Performance Metric is based on satisfaction of certain thresholds related to Platform Contribution. Platform Contribution means the amount calculated by the following formula: (i) total gross revenue for each of the Company's care delivery centers minus, (ii) for each such center, the sum of (a) medical claims expense and (b) cost of care, excluding depreciation and amortization for the applicable period. /s/ Robert Guenthner, attorney-in-fact for Timothy Cook 2022-02-23