Sec Form 4 Filing - Oasis Petroleum Inc. @ Oasis Midstream Partners LP - 2021-06-29

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 Oasis Petroleum Inc. 2. Issuer Name and Ticker or Trading Symbol Oasis Midstream Partners LP [ OMP] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 1001 FANNIN ST., SUITE 1500 3. Date of Earliest Transaction (MM/DD/YY) 06/29/2021 (Street) HOUSTON, TX77002 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ 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 units representing limited partner interests 06/29/2021 J( 1 ) 3,623,188 ( 1 ) D $ 24 ( 1 ) 33,846,032 I See Footnote ( 2 )

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 Call Option ("obligation to sell") $ 24 06/29/2021 J 543,478 ( 3 ) ( 3 ) 07/26/2021 Common units representing limited partner interests 543,478 $ 24 ( 3 ) 543,478 I See Footnotes ( 2 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Oasis Petroleum Inc. 1001 FANNIN ST., SUITE 1500 HOUSTON, TX77002 X Oasis Petroleum LLC 1001 FANNIN ST., SUITE 1500 HOUSTON, TX77002 X OMS Holdings LLC 1001 FANNIN ST., SUITE 1500 HOUSTON, TX77002 X Signatures /s/ Nickolas J. Lorentzatos, Executive Vice President, General Counsel and Corporate Secretary of Oasis Petroleum Inc. 07/01/2021 Signature of Reporting Person Date /s/ Nickolas J. Lorentzatos, Executive Vice President, General Counsel and Corporate Secretary of Oasis Petroleum LLC 07/01/2021 Signature of Reporting Person Date /s/ Nickolas J. Lorentzatos, Executive Vice President, General Counsel and Corporate Secretary of OMS Holding LLC 07/01/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The Issuer redeemed from Oasis Petroleum Inc. ("OAS") these common units representing limited partner interests ("Common Units") held by OMS Holdings LLC ("OMS Holdings") in connection with, and in the same quantity as were offered in, the Issuer's public offering of Common Units which closed on June 29, 2021 (the "Offering"). ( 2 )This Form 4 is being jointly filed by OMS Holdings, Oasis Petroleum LLC ("Oasis Petroleum") and OAS. As of June 29, 2021, OMS Holdings directly owns 33,846,032 Common Units, Oasis Petroleum directly owns 100% of the outstanding membership interests in OMS Holdings and OAS directly owns 100% of the outstanding membership interests in Oasis Petroleum. Accordingly, OAS and Oasis Petroleum may be deemed to be indirect beneficial owners of the securities of the Issuer held by OMS Holdings. ( 3 )Under the underwriting agreement entered into in connection with the Offering, the Issuer granted the underwriter a 30-day over-allotment option to purchase an aggregate 543,478 additional Common Units. Upon the exercise of the option, Issuer will redeem from OAS, at a price per Common Unit equal to $24.00, a number of Common Units held by OMS Holdings equal to the number of additional Common Units purchased by the underwriter.

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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