Sec Form 4 Filing - Silver Run Sponsor II, LLC @ Alta Mesa Resources, Inc. /DE - 2018-02-09

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 Silver Run Sponsor II, LLC 2. Issuer Name and Ticker or Trading Symbol Alta Mesa Resources, Inc. /DE [ AMR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O RIVERSTONE HOLDINGS LLC, 712 FIFTH AVENUE, 36TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 02/09/2018 (Street) NEW YORK, NY10019 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 Class A Common Stock 02/09/2018 A 40,000,000 A $ 10 40,000,000 I See footnotes ( 1 ) ( 5 ) ( 6 ) Class A Common Stock 02/09/2018 C 25,776,000 A 65,776,000 I See footnotes ( 1 ) ( 5 ) ( 6 ) Class C Common Stock 02/09/2018 A 20,000,000 A 20,000,000 I See footnotes ( 3 ) ( 5 ) ( 6 )

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 Warrants (right to buy) $ 11.5 02/09/2018 A 28,466,666 03/11/2018 02/09/2023 Class A Common Stock 28,466,666 $ 1.5 28,466,666 I See footnotes ( 4 ) ( 5 ) ( 6 ) Class B Common Stock ( 2 ) 02/09/2018 C 25,776,000 ( 2 ) ( 2 ) Class A Common Stock 25,776,000 $ 0 0 I See footnotes ( 2 ) ( 5 ) ( 6 ) Common Units ( 3 ) 02/09/2018 A 20,000,000 ( 3 ) ( 3 ) Class A Common Stock 20,000,000 ( 3 ) 20,000,000 I See footnotes ( 3 ) ( 5 ) ( 6 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Silver Run Sponsor II, LLC C/O RIVERSTONE HOLDINGS LLC 712 FIFTH AVENUE, 36TH FLOOR NEW YORK, NY10019 X X Riverstone VI SR II Holdings, L.P. C/O RIVERSTONE HOLDINGS LLC 712 FIFTH AVENUE, 36TH FLOOR NEW YORK, NY10019 X Riverstone Energy VI Holdings GP, LLC C/O RIVERSTONE HOLDINGS LLC 712 FIFTH AVENUE, 36TH FLOOR NEW YORK, NY10019 X Riverstone Energy Partners VI, L.P. C/O RIVERSTONE HOLDINGS LLC 712 FIFTH AVENUE, 36TH FLOOR NEW YORK, NY10019 X Riverstone Energy GP VI, LLC C/O RIVERSTONE HOLDINGS LLC 712 FIFTH AVENUE, 36TH FLOOR NEW YORK, NY10019 X Riverstone Energy GP VI Corp. C/O RIVERSTONE HOLDINGS LLC 712 FIFTH AVENUE, 36TH FLOOR NEW YORK, NY10019 X RIVERSTONE HOLDINGS LLC C/O RIVERSTONE HOLDINGS LLC 712 FIFTH AVENUE, 36TH FLOOR NEW YORK, NY10019 X LAPEYRE PIERRE F JR C/O RIVERSTONE HOLDINGS LLC 712 FIFTH AVENUE, 36TH FLOOR NEW YORK, NY10019 X X LEUSCHEN DAVID M C/O RIVERSTONE HOLDINGS LLC 712 FIFTH AVENUE, 36TH FLOOR NEW YORK, NY10019 X X Signatures Silver Run Sponsor II, LLC By: /s/ Thomas J. Walker, Managing Director 02/13/2018 Signature of Reporting Person Date Riverstone VI SR II Holdings, L.P. By: Riverstone Energy VI Holdings GP, LLC , its general partner By: /s/ Thomas J. Walker, Managing Director 02/13/2018 Signature of Reporting Person Date Riverstone Energy VI Holdings GP, LLC By: /s/ Thomas J. Walker, Managing Director 02/13/2018 Signature of Reporting Person Date Riverstone Energy Partners VI, L.P. By: Riverstone Energy GP VI, LLC, its general partner By: /s/ Thomas J. Walker, Managing Director 02/13/2018 Signature of Reporting Person Date Riverstone Energy GP VI, LLC By: /s/ Thomas J. Walker, Managing Director 02/13/2018 Signature of Reporting Person Date Riverstone Energy GP VI Corp By: /s/ Thomas J. Walker, Vice President 02/13/2018 Signature of Reporting Person Date Riverstone Holdings LLC By: /s/ Thomas J. Walker, Authorized Person 02/13/2018 Signature of Reporting Person Date David M. Lesuchen By: /s/ Thomas J. Walker, Attorney-in-Fact 02/13/2018 Signature of Reporting Person Date Pierre F. Lapeyre, Jr. By: /s/ Thomas J. Walker, Attorney-in-Fact 02/13/2018 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Following the transactions reported herein, includes 16,548,894 shares held of record by Silver Run Sponsor II, LLC ("Sponsor"), 18,522,000 shares held of record by Riverstone VI SR II Holdings, L.P. ("SR II Holdings"), 25,857,148 shares held by Riverstone AMR Partners, L.P. ("AMR Partners"), 1,720,243 shares held of record by Riverstone AMR Partners-U, LLC ("AMR Partners-U") and 3,127,715 shares held of record by Riverstone AMR Partners-T, L.P. ( 2 )Prior to the transactions reported herein, the Class B Common Stock was held of record by Sponsor. In connection with the closing of the initial business combination of the Issuer (the "Initial Business Combination"), each share of Class B Common Stock automatically converted into Class A Common Stock of the Issuer on a 1-to-1 basis. ( 3 )Held of record by Riverstone VI Alta Mesa Holdings, L.P. ("Riverstone Contributor" and, together with the Sponsor, SR II Holdings, AMR Partners, AMR Partners-U and AMR Partners-T, the "Riverstone Funds"). In connection with the closing of the Issuer's Initial Business Combination, the Issuer issued Riverstone Contributor 20,000,000 shares of Class C Common Stock and caused SRII Opco, LP to issue an equal number of its common units (the "SRII Opco Common Units") to the Riverstone Contributor in exchange for certain assets of Riverstone Contributor. The SRII Opco Common Units may, at the option of Riverstone Contributor, be redeemed for shares of Class A Common Stock on a one-to-one basis at any time after 180 days after the closing of the Initial Business Combination and have no expiration date. Upon redemption, an equal number of shares of Class C Common Stock will be cancelled. ( 4 )Includes 9,716,012 warrants held of record by Sponsor, 13,333,333 warrants held of record by SR II Holdings, 4,561,992 warrants held by AMR Partners, 303,504 warrants held of record by AMR Partners-U and 551,825 warrants held of record by AMR Partners-T. Of these, 15,133,333 warrants were purchased simultaneous with the closing of the Issuer's initial public offering on March 29, 2017, and 13,333,333 warrants were issued pursuant to a forward purchase agreement dated as of March 17, 2017. The warrants became exercisable after the completion of the Initial Business Combination, which occurred on February 9, 2018. ( 5 )David M. Leuschen and Pierre F. Lapeyre, Jr. are the members of Riverstone Management Group, L.L.C. ("Riverstone Management"), which is the general partner of Riverstone/Gower Mgmt Co Holdings, L.P. ("Riverstone/Gower"), which is the sole member of Riverstone Holdings LLC ("Holdings"), which is the sole shareholder of Riverstone Energy GP VI Corp, which is the managing member of Riverstone Energy GP VI, LLC ("Riverstone Energy GP") which is the general partner of Riverstone Energy Partners VI, L.P., which is the general partner of AMR Partners, the manager of AMR Partners-U and the managing member of Riverstone Energy VI Holdings GP, LLC, which is the general partner of each of the Riverstone Contributor and SR II Holdings, which is the sole and managing member of Sponsor. Riverstone Energy GP is also the sole member of Riverstone Energy Partners VI (Non-U.S.), LLC, which is the general partner of AMR Partners-T, L.P. ( 6 )Riverstone Energy GP is managed by a managing committee consisting of Pierre F. Lapeyre, Jr., David M. Leuschen, E. Bartow Jones, N. John Lancaster, Baran Tekkora and Robert M. Tichio. As such, each of Riverstone Energy GP, Riverstone Energy GP VI Corp, Holdings, Riverstone/Gower, Riverstone Management, Mr. Leuschen and Mr. Lapeyre may be deemed to have or share beneficial ownership of the securities held directly by the Riverstone Funds. Each such entity or person disclaims any such beneficial ownership of such securities except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that the reporting person is the beneficial owner of the securities for purposes of Section 16 or for any other purpose.

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