TUSK · Insider Trading
Mammoth Energy Services, Inc. Common Stock
Every open-market purchase and sale reported by TUSK officers, directors and 10%+ beneficial owners on SEC Form 4, which must be filed within two business days of the transaction. Sales often reflect scheduled 10b5-1 plans or tax withholding rather than a directional view, so read counts alongside the size and the filer.
| Filed | Insider | Role | Type | Shares | Value |
|---|---|---|---|---|---|
| 2026-09-17 | Mark Lawrence Plaumann | Director | Buy | +5,000 | +$15.00K |
| 2026-07-01 | Phillip Lancaster | Director | J | +68,152 | — |
| 2026-06-22 | Paul M. Jacobi | Chief Business Officer | J | +3,211 | — |
| 2026-06-22 | CD Holding Company, LLC | 10%+ Owner | J | +6,470,441 | — |
| 2026-06-22 | Amron Holdings LLC | Director | J | +29,450 | — |
| 2026-06-22 | Joseph Jacobs | Chief Business Officer | MIXED | +11,447,137 | +$10.47M |
| 2026-06-15 | Arthur H Amron | Director | Buy | +4,500 | +$14.61K |
| 2026-05-28 | Arthur H Amron | Director | Buy | +5,500 | +$17.85K |
| 2025-12-15 | Arthur H Amron | Director | Buy | +10,000 | +$18.90K |
| 2025-05-27 | Arthur L Smith | Director | Sell | −20,000 | −$50.20K |
| 2025-05-21 | Arthur L Smith | Director | Sell | −65,000 | −$162.85K |
| 2024-12-16 | Arthur H Amron | Director | Buy | +1,000 | +$2.97K |
| 2024-11-26 | Corey J. Booker | Director | Sell | −25,000 | −$86.35K |
| 2024-11-22 | Corey J. Booker | Director | Sell | −11,709 | −$37.85K |
| 2024-11-15 | Corey J. Booker | Director | Sell | −10,707 | −$38.72K |
| 2024-11-12 | Corey J. Booker | Director | Sell | −3,683 | −$13.35K |
| 2024-06-14 | Paul M. Jacobi | Director | A | +27,856 | — |
| 2024-06-14 | James D Palm | Director | A | +27,856 | — |
| 2024-06-14 | Corey J. Booker | Director | A | +27,856 | — |
| 2024-06-14 | Arthur H Amron | Director | A | +27,856 | — |
| 2024-06-14 | Arthur L Smith | Director | A | +27,856 | — |
| 2024-05-30 | Arthur H Amron | Director | Buy | +5,000 | +$18.09K |
| 2024-03-14 | Arthur H Amron | Director | Buy | +3,000 | +$11.16K |
| 2024-03-14 | Joseph Jacobs | Director | J | −535,366 | — |
| 2023-12-19 | Arty Straehla | Chief Executive Officer | Sell | −70,000 | −$305.44K |
| 2023-12-15 | Arty Straehla | Chief Executive Officer | Sell | −120,000 | −$528.24K |
| 2023-06-08 | James D Palm | Director | A | +23,810 | — |
| 2023-06-08 | Arthur H Amron | Director | A | +23,810 | — |
| 2023-06-08 | Paul M. Jacobi | Director | A | +23,810 | — |
| 2023-06-08 | Corey J. Booker | Director | A | +23,810 | — |
| 2023-06-08 | Arthur L Smith | Director | A | +23,810 | — |
| 2023-03-07 | Mark E. Layton | CFO and Secretary | F | −36,375 | −$201.88K |
| 2023-03-07 | Arty Straehla | Chief Executive Officer | F | −129,220 | −$717.17K |
| 2022-11-14 | Arthur L Smith | Director | Sell | −20,000 | −$141.32K |
| 2022-06-30 | Arthur H Amron | Director | A | +45,662 | — |
| 2022-06-30 | James D Palm | Director | A | +45,662 | — |
| 2022-06-30 | Corey J. Booker | Director | A | +45,662 | — |
| 2022-06-30 | Paul M. Jacobi | Director | A | +45,662 | — |
| 2022-06-30 | Arthur L Smith | Director | A | +45,662 | — |
| 2022-06-21 | WEXFORD CAPITAL LP | Director | Buy | +45,382 | +$96.98K |
| 2022-06-15 | Joseph Jacobs | Director | Buy | +50,802 | +$117.35K |
| 2022-06-10 | Wexford GP LLC | Director | Buy | +97,768 | +$241.38K |
| 2022-03-11 | Mark E. Layton | CFO and Secretary | Sell | −40,417 | −$82.33K |
| 2021-12-14 | Arthur L Smith | Director | Buy | +25,000 | +$50.00K |
| 2021-06-04 | Paul M. Jacobi | Director | A | +25,641 | — |
| 2021-06-04 | James D Palm | Director | A | +25,641 | — |
| 2021-06-04 | Arthur L Smith | Director | A | +25,641 | — |
| 2021-06-04 | Arthur H Amron | Director | A | +25,641 | — |
| 2021-06-04 | Corey J. Booker | Director | A | +25,641 | — |
| 2021-03-11 | Mark E. Layton | CFO and Secretary | Sell | −55,789 | −$290.98K |
| Insider | Role | Shares Held | Value |
|---|---|---|---|
| Joseph Jacobs | Chief Business Officer | 12,071,823 | $37.91M |
| CD Holding Company, LLC | 10%+ Owner | 6,470,441 | $20.32M |
| Phillip Lancaster | Director | 159,445 | $500.66K |
| Corey J. Booker | Director | 140,488 | $441.13K |
| Arthur L Smith | Director | 130,034 | $408.31K |
| Amron Holdings LLC | Director | 96,585 | $303.28K |
| Arthur H Amron | Director | 67,135 | $210.80K |
| Paul M. Jacobi | Chief Business Officer | 31,067 | $97.55K |
| Mark Lawrence Plaumann | Director | 5,000 | $15.70K |
Form 4 reports a change in beneficial ownership by an officer, director or 10%+ holder, and must be filed within two business days of the transaction — so this is close to real time, unlike the 45-day-lagged 13F institutional data.
Transaction codes matter more than the raw buy/sell count. Code P is an open-market purchase — an insider choosing to buy with their own money, which is the signal most research treats as informative. Code S is a sale, but sales are frequently pre-scheduled under a 10b5-1 plan or cover tax withholding on vesting equity, so a run of sales often says nothing directional. Codes A and M are grants and option exercises rather than open-market decisions.
Full filing history and per-insider positions are on the TUSK quote page; the site-wide leaderboard is on the insider transactions hub.
Market data may be delayed, incomplete, or inaccurate. Not a recommendation to buy, sell, or hold any security. Verify quotes with your broker before trading. See Terms §17.