Sec Form 4 Filing - PYKOSZ MICHAEL T @ Oak Street Health, Inc. - 2020-08-05

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person PYKOSZ MICHAEL T 2. Issuer Name and Ticker or Trading Symbol Oak Street Health, Inc. [ ?OSH?] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Exec. Officer, Director (Last) (First) (Middle) C/O OAK STREET HEALTH, INC., 30 W. MONROE STREET, SUITE 1200 3. Date of Earliest Transaction (MM/DD/YY) 08/05/2020 (Street) CHICAGO, IL60603 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common stock, $0.001 par value 08/10/2020 J( 1 )( 2 ) 8,946,192 A $ 0 8,946,192 D Common stock, $0.001 par value 08/10/2020 A 48 A $ 0 8,946,240 D Common stock, $0.001 par value 08/10/2020 J( 1 )( 2 ) 790,274 A $ 0 790,274 I Through Mike Pykosz Gift Trust

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Employee Stock Options (Right to Buy) $ 21 08/05/2020 A 275,270 ( 3 ) 08/05/2030 Common Stock, par value $0.001 275,270 $ 0 275,270 D Employee Stock Options (Right to Buy) $ 21 08/05/2020 A 106,780 ( 3 ) 08/05/2030 Common Stock, par value $0.001 106,780 $ 0 106,780 I Through Mike Pykosz Gift Trust Employee Stock Options (Right to Buy) $ 21 08/05/2020 A 443,534 ( 4 ) 08/05/2030 Common Stock, par value $0.001 443,534 $ 0 443,534 D Employee Stock Options (Right to Buy) $ 21 08/05/2020 A 22,044 ( 5 ) 08/05/2030 Common Stock, par value $0.001 22,044 $ 0 22,044 D Employee Stock Options (Right to Buy) $ 21 08/05/2020 A 14,535 ( 6 ) 08/05/2030 Common Stock, par value $0.001 14,535 $ 0 14,535 D Employee Stock Options (Right to Buy) $ 21 08/05/2020 A 137,168 ( 7 ) 08/05/2030 Common Stock, par value $0.001 137,168 $ 0 137,168 D Employee Stock Options (Right to Buy) $ 21 08/05/2020 A 13,556 ( 8 ) 08/05/2030 Common Stock, par value $0.001 13,556 $ 0 13,556 D Employee Stock Options (Right to Buy) $ 21 08/05/2020 A 10,176 ( 9 ) 08/05/2030 Common Stock, par value $0.001 10,176 $ 0 10,176 D Employee Stock Options (Right to Buy) $ 21 08/05/2020 A 64,190 ( 10 ) 08/05/2030 Common Stock, par value $0.001 64,190 $ 0 64,190 D Employee Stock Options (Right to Buy) $ 21 08/05/2020 A 61,272 ( 10 ) 08/05/2030 Common Stock, par value $0.001 61,272 $ 0 61,272 I Through the Mike Pykosz Gift Trust Employee Stock Options (Right to Buy) $ 21 08/05/2020 A 335,266 ( 11 ) 08/05/2030 Common Stock, par value $0.001 335,266 $ 0 335,266 D Employee Stock Options (Right to Buy) $ 21 08/05/2020 A < span class="form4-data"> 335,262 ( 12 ) 08/05/2030 Common Stock, par value $0.001 335,262 $ 0 335,262 D Employee Stock Options (Right to Buy) $ 21 08/05/2020 A 3,300,398 ( 13 ) 08/05/2030 Common Stock, par value $0.001 3,300,398 $ 0 3,300,398 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other PYKOSZ MICHAEL T C/O OAK STREET HEALTH, INC. 30 W. MONROE STREET, SUITE 1200 CHICAGO, IL60603 X Chief Exec. Officer, Director Signatures /s/ Robert Guenthner, as attorney-in-fact for Michael T. Pykosz 08/12/2020 Signature of Reporting Person Date

Explanation of Responses:

( 1 )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 founders units and 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"). ( 2 )Represents shares of the Issuer's common stock, par value $0.001 (the "Shares") issued in exchange for vested and unvested incentive units and founders 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. Shares issued in exchange for the unvested incentive units were issued under the Oak Street Health Omnibus Incentive Plan (the "Plan"). ( 3 )Represents options issued under the Plan in exchange for vested incentive units in Management Holding in connection with the Organizational Transactions. Such options are fully vested and exercisable. ( 4 )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, 2022. ( 5 )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 in three equal quarterly installments beginning on October 3, 2020. ( 6 )Represents options issued under the Plan in exchange for unvested time-vesting incentive units in Management Holding in connection with the Organizational Transactions. These options will vest in five equal quarterly installments beginning on August 18, 2020. ( 7 )Represents options issued under the Plan in exchange for unvested time-vesting incentive units in Management Holding in connection with the Organizational Transactions. These options will vest in eight equal quarterly installments beginning on October 23, 2020. ( 8 )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 June 14, 2023. ( 9 )Represents options issued under the Plan in exchange for unvested time-vesting incentive units in Management Holding in connection with the Organizational Transactions. These options will vest in twelve equal quarterly installments beginning on August 15, 2020. ( 10 )Represents options issued under the Plan in exchange for unvested time-vesting incentive units in Management Holding in connection with the Organizational Transactions. These options will cliff vest 100% on January 1, 2021. ( 11 )Represents options issued under the Plan in exchange for unvested time-vesting incentive units in Management Holding in connection with the Organizational Transactions. These options will vest 50% on each of January 1, 2022 and January 1, 2023. ( 12 )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. ( 13 )Represents options issued under the Plan in exchange for unvested time-vesting incentive units in Management Holding in connection with the Organizational Transactions. These options will vest 25% beginning on June 11, 2021 and then in twelve equal quarterly installments beginning on September 11, 2021.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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