Mammoth Energy CEO Phil Lancaster resigns; son Bernard named COO; board changes

MAMMOTH ENERGY SERVICES, INC.

CEO Phil Lancaster resigns effective June 30, 2025; will become non-voting board observer June 11.
Bernard Lancaster, son of Phil, appointed COO and Principal Executive Officer effective July 1, 2025.
Paul Jacobi appointed Chief Business Officer effective July 1; resigns from board committees, loses independent status.
Arthur Smith to retire from board at June 11 annual meeting; Mark Plaumann appointed audit committee chair and director.

item 5.02

Executive movements

Machine-extracted from this filing. Every card cites the SEC source. See all recent executive movements.

Appointed

Paul Jacobi

Chief Business Officer

TUSK · MAMMOTH ENERGY SERVICES, INC.

Effective: 2025-07-01
Filed: Jun 05, 2025 23:59 UTC

the Board named Paul Jacobi as the Company's Chief Business Officer effective July 1, 2025.

Appointed

Bernard Lancaster

Chief Operating Officer and Principal Executive Officer

TUSK · MAMMOTH ENERGY SERVICES, INC.

Effective: 2025-07-01
Filed: Jun 05, 2025 23:59 UTC

the Board named Bernard Lancaster as Chief Operating Officer and Principal Executive Officer of the Company effective July 1, 2025.

Departed

Arthur Smith

Director

TUSK · MAMMOTH ENERGY SERVICES, INC.

Effective: 2025-06-11
Filed: Jun 05, 2025 23:59 UTC

Arthur Smith, who has served as a director of the Company since the Company's initial public offering, will not stand for re-election at the Company's 2025 Annual Meeting of Stockholders on June 11, 2025 (the "2025 Annual Meeting"), and will retire as a director, chairman of the audit committee and member of the compensation committee and nominating and corporate governance committee, effective as of the date of the 2025 Annual Meeting.

Departed

Phil Lancaster

Chief Executive Officer

TUSK · MAMMOTH ENERGY SERVICES, INC.

Effective: 2025-06-30
Successor: Bernard Lancaster
Filed: Jun 05, 2025 23:59 UTC

Mr. P. Lancaster has resigned from his CEO with Mammoth effective as of June 30, 2025.

Source: SEC EDGAR

accession 0001628280-25-029661

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