Form4insider filings, from the source

Company · CIK 0001679268 · SIC 1389 — Oil & Gas Field Services, NEC · Nasdaq

MAMMOTH ENERGY SERVICES, INC. · TUSK

Insider activity reported against this company. All insider holders · On EDGAR ↗

1M3M6M1Y2YAll datashares as filed — not split-adjusted
Open-market buys & salesbuys $10.8M · 8sales $172.0M · 12net −$161.2M
$100k$100k$10M$10M$1B$1BbuyssalesOct 2016Jun 2018Feb 2020Oct 2021May 2023Jan 2025Sep 2026

Reported at this company — common stock

TradeReported (ET)InsiderSharesAvg priceTotalOwned afterΔ stakeFlags
Sep 16, 2026 PForm 4 →Sep 17, 4:50 pm EDTMark Lawrence PlaumannDirector5,000$3.00$15,0005,000—
Jun 26, 2026 JForm 4 →Jul 1, 4:56 pm EDTPhillip LancasterDirector68,152——159,445— late
Jun 17, 2026 JForm 4 →Jun 22, 4:42 pm EDTPaul M. JacobiChief Business Officer, Director3,211——31,067—
Jun 17, 2026 JForm 4 →Jun 22, 4:32 pm EDTArthur H Amron +1Director29,450——10,329—
Jun 17, 2026 PForm 4 →Jun 22, 4:26 pm EDTWEXFORD CAPITAL LP +3Chief Business Officer, Director, 10% Owner4,019,574$2.60$10,468,17710,620,789+60.9%
Jun 17, 2026 JForm 4 →Jun 22, 4:26 pm EDTWEXFORD CAPITAL LP +3Chief Business Officer, Director, 10% Owner7,427,563——6,601,215—
Jun 17, 2026 JForm 4 →Jun 22, 4:18 pm EDTCharles E Davidson +110% Owner6,470,441——4,066,610—
Jun 11, 2026 PForm 4 →Jun 15, 4:28 pm EDTArthur H AmronDirector4,500$3.25$14,61067,135+7.18%
Jan 25, 2019 AForm 4 →Jan 29, 5:41 pm ESTArthur H AmronDirector1,549——1,549— plan?
Dec 3, 2018 SForm 4 →Dec 6, 4:05 pm ESTArthur L SmithDirector6,000$24.85$149,0990−100% plan?
Nov 8, 2018 SForm 4 →Nov 13, 4:12 pm ESTArty StraehlaChief Executive Officer, Director38,841$26.68$1,036,442185,317−17.3% plan? late
Nov 8, 2018 SForm 4 →Nov 13, 4:09 pm ESTMark E. LaytonCFO and Secretary1,136$27.13$30,82051,566−2.16% plan? late
Jul 30, 2018 SForm 4 →Aug 1, 7:27 pm EDTGULFPORT ENERGY CORPDirector, 10% Owner118,974$38.01$4,522,2029,829,548−1.20% plan?
Jul 30, 2018 SForm 4 →Aug 1, 5:10 pm EDTMEH SUB LLC +4Director, 10% Owner266,026$38.01$10,111,64821,978,893−1.20% plan?
Jun 29, 2018 SForm 4 →Jul 3, 4:22 pm EDTGULFPORT ENERGY CORPDirector, 10% Owner1,235,600$38.01$46,965,1569,948,522−11.0% plan?
Jun 29, 2018 SForm 4 →Jul 3, 2:43 pm EDTMEH SUB LLC +4Director, 10% Owner2,764,400$38.01$105,074,84422,244,919−11.1% plan?
Jun 7, 2018 AForm 4 →Jun 11, 6:08 pm EDTPaul K Heerwagen IVDirector2,655——2,655— plan?
Jun 7, 2018 AForm 4 →Jun 11, 6:08 pm EDTJames D PalmDirector2,655——19,725— plan?
Jun 7, 2018 AForm 4 →Jun 11, 6:08 pm EDTMatthew RossDirector2,655——12,235— plan?
Jun 7, 2018 AForm 4 →Jun 11, 6:06 pm EDTArthur L SmithDirector2,655——12,235— plan?
Jun 7, 2018 AForm 4 →Jun 11, 4:33 pm EDTMarc T McCarthyDirector2,655——2,655— plan?
Mar 1, 2018 SForm 4 →Mar 7, 8:35 pm ESTMark E. LaytonCFO and Secretary4,373$26.13$114,25252,702−7.66% plan? late
Feb 2, 2018 AForm 4 →Feb 6, 6:09 pm ESTPaul K Heerwagen IVDirector2,913——2,913— plan?
Feb 2, 2018 AForm 4 →Feb 6, 6:07 pm ESTMatthew RossDirector2,913——9,580— plan?
Feb 2, 2018 AForm 4 →Feb 6, 6:06 pm ESTArthur L SmithDirector2,913——9,580— plan?
Feb 2, 2018 AForm 4 →Feb 6, 6:06 pm ESTJames D PalmDirector4,370——17,070— plan?
Feb 2, 2018 AForm 4 →Feb 6, 5:39 pm ESTMarc T McCarthyDirector2,913——2,913— plan?
Nov 14, 2017 SForm 4 →Nov 16, 6:58 pm ESTMark E. LaytonCFO and Secretary925$19.01$17,58757,075−1.59% plan?
Nov 14, 2017 SForm 4 →Nov 16, 6:58 pm ESTArty StraehlaChief Executive Officer, Director25,842$18.45$476,762224,158−10.3% plan?
Aug 24, 2017 PForm 4 →Aug 28, 7:58 pm EDTJames D PalmDirector6,000$12.75$76,52312,700+89.6% plan?
Jun 9, 2017 PForm 4 →Jun 13, 5:01 pm EDTArthur L SmithDirector6,000$16.91$101,4576,000— plan?
Jun 8, 2017 AForm 4 →Jun 22, 4:47 pm EDTMEH SUB LLC +4Director, 10% Owner4,565,416——25,009,319— plan? late
Jun 5, 2017 AForm 5 →Feb 14, 2018, 8:52 pm ESTGULFPORT ENERGY CORPDirector, 10% Owner2,098,137——11,181,467— plan?
Feb 28, 2017 PForm 4 →Mar 2, 6:36 pm ESTArty StraehlaChief Executive Officer, Director460$21.76$10,008460— plan?
Feb 21, 2017 AForm 4 →Feb 23, 5:57 pm ESTMark E. LaytonCFO and Secretary40,000——58,000— plan?
Nov 7, 2016 AForm 4 →Nov 9, 8:19 pm ESTMatthew RossDirector6,667——6,667— plan?
Oct 19, 2016 AForm 4 →Oct 21, 8:45 pm EDTAaron GaydosikDirector6,667——6,667— plan?
Oct 19, 2016 SForm 4 →Oct 21, 8:38 pm EDTGULFPORT ENERGY CORPDirector, 10% Owner76,250$14.06$1,072,2669,080,417−0.83% plan?
Oct 19, 2016 AForm 4 →Oct 21, 6:58 pm EDTMark E. LaytonCFO and Secretary15,000——18,000— plan?
Oct 19, 2016 PForm 4 →Oct 21, 6:58 pm EDTMark E. LaytonCFO and Secretary3,000$15.00$45,0003,000— plan?
Oct 19, 2016 AForm 4 →Oct 21, 6:56 pm EDTArthur L SmithDirector6,667——6,667— plan?
Oct 19, 2016 AForm 4 →Oct 21, 6:55 pm EDTArty StraehlaChief Executive Officer, Director250,000——251,332— plan?
Oct 19, 2016 PForm 4 →Oct 21, 6:55 pm EDTArty StraehlaChief Executive Officer, Director1,332$15.00$19,9801,332— plan?
Oct 19, 2016 AForm 4 →Oct 21, 6:55 pm EDTAndre WeissDirector6,667——6,667— plan?
Oct 19, 2016 AForm 4 →Oct 21, 4:22 pm EDTMarc T McCarthyDirector6,667——6,667— plan?
Oct 19, 2016 SForm 4 →Oct 21, 4:12 pm EDTMammoth Energy Holdings LLC +4Director, 10% Owner171,797$14.06$2,415,89520,445,923−0.83% plan?
Jan 9, 2016 AForm 4 →Jan 10, 2017, 6:26 pm ESTPaul K Heerwagen IVDirector4,444——4,444— plan? late

Reported at this company — derivatives (options, RSUs, warrants)

No reported derivative activity in this period.