Western Midstream and Aris Water Solutions Announce Election Deadline for Aris Securityholders to Elect Form of Merger Consideration and Expiration of Hart-Scott-Rodino Act Waiting Period

Western Midstream Partners, LP (NYSE: WES) (“WES”) and Aris Water Solutions, Inc. (NYSE: ARIS) (“Aris”) jointly announced today that, in connection with WES’s pending acquisition of Aris (the “Transaction”), the deadline for Aris securityholders to elect the form of merger consideration they wish to receive in the Transaction, as described in more detail below, has been set for 5:00 p.m., New York time, on October 7, 2025 (such deadline, as it may be extended, the “Election Deadline”). The Election Deadline is based on WES’s and Aris’s expectation that the Transaction will close on October 15, 2025, subject to the approval of the stockholders of Aris and the satisfaction of other customary closing conditions.

Aris securityholders of record wishing to make an election as to the form of consideration they wish to receive must deliver a properly completed and signed election form or online election (the “Election Form”), together with all required documents and materials, to Computershare Trust Company, N.A. (the “Exchange Agent”) by the Election Deadline. An election will be valid only if a properly completed Election Form, together with all required documents and materials set forth in the Election Form and the instructions thereto, is received by the Exchange Agent by the Election Deadline.

Aris securityholders who hold shares through a bank, broker, or other nominee should contact their bank, broker, or other nominee for instructions on how to make an election for the form of consideration they wish to receive. Such securityholders who hold shares through a bank, broker, or other nominee may be subject to an earlier election deadline and must carefully review and properly complete any election materials they received from their bank, broker or other nominee regarding how to make an election.

As further described in (i) the Agreement and Plan of Merger, dated as of August 6, 2025, by and among WES, Aris and the other parties thereto (the “Merger Agreement”), (ii) the proxy statement of Aris and prospectus of WES (the “Proxy Statement/Prospectus”), included in the registration statement on Form S-4 filed by WES with the Securities and Exchange Commission (the “SEC”), which was declared effective on September 12, 2025, (the “Registration Statement”) and (iii) the Election Form and accompanying election materials, each issued and outstanding share of Class A common stock, par value $0.01 per share, of Aris and each Aris OpCo Stapled Unit (comprising one unit of Aris Water Holdings, LLC and one corresponding share of Class B common stock, par value $0.01 per share, of Aris) shall, subject to certain exceptions as set forth in the Merger Agreement, have the right to elect to receive: (i) 0.625 common units representing limited partner interests in WES (“WES Common Units” and, such consideration, the “Common Unit Election Consideration”), (ii) a combination of $7.00 in cash (without interest) and 0.450 WES Common Units, or (iii) $25.00 in cash (without interest) (the “Cash Election Consideration”). The Cash Election Consideration is subject to proration to ensure that the total cash consideration payable in the Transaction will not exceed $415.0 million.