MAMMOTH ENERGY SERVICES, INC. — Proxy Solicitation & Information Statement 2026

May 15, 2026

DEFA14A 1 a2026-05x15defa14a.htm DEFA14A Document created using Wdesk Copyright 2026 Workiva Document

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

ý Filed by Registrant

Check the appropriate box

¨ Preliminary Proxy Statement

¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

¨ Definitive Proxy Statement

ý Definitive Additional Materials

¨ Soliciting Material under § 240.14a-12

Mammoth Energy Services, Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than Registrant)

Payment of Filing Fee (Check the appropriate box):

ý No fee required

¨ Fee paid previously with written preliminary materials

¨ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11