X0306 4 2019-05-28 0 0001748773 RATTLER MIDSTREAM LP RTLR 0001539838 Diamondback Energy, Inc. 500 WEST TEXAS AVENUE, SUITE 1200 MIDLAND TX 79701 1 0 0 0 0001771397 Energen Resources Corp 500 WEST TEXAS AVENUE, SUITE 1200 MIDLAND TX 79701 1 0 0 0 Class B Units representing limited partner interests 2019-05-28 4 A 0 107815152 A Common units representing limited partner interests 107815152 107815152 I By Subsidiary Units in Rattler Midstream Operating LLC 2019-05-28 4 A 0 107815152 A Common units representing limited partner interests 107815152 107815152 I By Subsidiary Pursuant to an exchange agreement, dated May 28, 2019, certain holders can tender units in Rattler Midstream Operating LLC ("OpCo") and an equal number of Class B units ("Class B Units") representing limited partner interests in Rattler Midstream LP (the "Partnership") (together, the "Tendered Units") for redemption by the Partnership and OpCo. Such holder has the right to receive, at the election of OpCo with the approval of the conflicts committee of the board of directors of Rattler Midstream GP LLC, the general partner of the Partnership (the "General Partner"), either the number of common units representing limited partner interests in the Partnership ("Common Units") equal to the number of Tendered Units or a cash payment equal to the sum of (i) the number of Tendered Units multiplied by the average daily trading price of the Common Units for the prior 20 days plus (ii) the number of Tendered Units multiplied by the quotient of $1,000,000 divided by the number of then outstanding (Footnote 1 continued) Class B Units. In addition, the Partnership has the right but not the obligation, to directly purchase such Tendered Units for, subject to the approval of the conflicts committee of the board of directors of the General Partner, cash or Common Units at its election. These securities were acquired by Energen Resources Corporation in connection with the contribution of $1,000,000 to the Partnership. These securities were acquired by Energen Resources Corporation in consideration for the tender of its previous membership interests in Rattler Midstream Operating LLC. This Form 4 is being filed jointly by Diamondback Energy, Inc. and Energen Resources Corporation (together, the "Reporting Persons"). Diamondback Energy, Inc. is the sole shareholder of Energen Corporation, which is the sole shareholder of Energen Resources Corporation, and Diamondback Energy, Inc. is the sole member of the General Partner, which owns the non-economic general partner interest in the Partnership. On the basis of the relationship between the Reporting Persons (whether directly or through their affiliates) and certain directors of the General Partner, the Reporting Persons may be deemed to be directors of the Issuer. /s/ Teresa L. Dick as Executive Vice President, Chief Accounting Officer and Assistant Secretary of Diamondback Energy, Inc. 2019-05-29 /s/ Teresa L. Dick as Executive Vice President, Chief Accounting Officer and Assistant Secretary of Energen Resources Corporation 2019-05-29