Plaumann Mark Lawrence

SEC source: 0001628280-26-062552 · wk-form4_1789678216.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 5,000

F1 · price: The price reported in Column 4 is a weighted average purchase price. These shares were purchased in multiple transactions at prices within a range. The reporting person undertakes to provide to Mammoth Energy Services, Inc., any security holder of Mammoth Energy Services, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price.

F2 · balance_after: Of the shares reported herein, 2,100 shares are held in a Roth IRA and 2,900 shares are held in a traditional IRA, each for the benefit of the Reporting Person.

SEC source: 0001539838-26-000152 · wk-form4_1787601691.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 12,437

SEC source: 0001539838-26-000128 · wk-form4_1781122116.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,437

SEC source: 0001539838-26-000110 · wk-form4_1779400643.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,937

F1 · shares: These securities are restricted stock units, each representing a contingent right to receive one share of common stock, par value $0.01 per share, of the issuer. These restricted stock units were granted to Mr. Plaumann as an annual non-employee director grant under the issuer's equity incentive plan and will vest on the earlier of the one-year anniversary of the date of grant and the date of the 2027 annual meeting of stockholders of the issuer.

F2 · balance_after: Reflects the transfer of 7,688 shares of Common Stock in a transaction exempt from reporting pursuant to Rule 16a-13.

SEC source: 0001539838-25-000117 · wk-form4_1750712915.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 5,267

F1 · shares: An aggregate of 2,965 shares of the issuer's common stock was distributed by Greyhawke Capital Advisors LLC ("Greyhawke") in an in-kind distribution to Mr. Plaumann in connection with the amendment of the Greyhawke limited liability company agreement executed by the members and the manager of Greyhawke on June 19, 2025 during the issuer's open trading window (the "Amended Greyhawke LLC Agreement").

SEC source: 0001539838-25-000103 · wk-form4_1747953503.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,302

F1 · shares: These securities are restricted stock units, each representing a contingent right to receive one share of common stock, par value $0.01 per share, of the issuer. These restricted stock units were granted to Mr. Plaumann as an annual non-employee director grant under the issuer's equity incentive plan and will vest on the earlier of the one-year anniversary of the date of grant and the date of the 2026 annual meeting of stockholders of the issuer.

F2 · balance_after: All of the 1,417 restricted stock units granted to Mr. Plaumann on May 21, 2025 have been assigned by Mr. Plaumann to Greyhawke Capital Advisors LLC ("Greyhawke") under the terms of his employment with Greyhawke. Mr. Plaumann is a managing member of Greyhawke and a holder of a 50% ownership interest in Greyhawke.

SEC source: 0001539838-24-000215 · wk-form4_1733780366.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,302

SEC source: 0001539838-24-000206 · wk-form4_1731622466.xml · nonDerivative · entry 5

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · By Greyhawke Capital Advisors LLC

Disclosed balance after: 9,236

F2 · ownership.direct: The remaining shares held by Greyhawke were previously assigned by Mr. Plaumann to Greyhawke under the terms of his employment with Greyhawke. As a managing member of Greyhawke and a holder of a 50% membership interest therein, Mr. Plaumann may be deemed to have a pecuniary interest in the securities held by Greyhawke.

SEC source: 0001539838-24-000206 · wk-form4_1731622466.xml · nonDerivative · entry 4

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,402

SEC source: 0001539838-24-000206 · wk-form4_1731622466.xml · nonDerivative · entry 3

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,712

SEC source: 0001539838-24-000206 · wk-form4_1731622466.xml · nonDerivative · entry 2

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 5,862

F1 · shares: These shares were distributed by Greyhawke Capital Advisors LLC ("Greyhawke") in a partial in-kind distribution to Mr. Plaumann and the Martin and Selma Rosen GST Trust FBO Robert Rosen and Descendants U/A December 15, 2015 (the "MS Trust") proportionate to their respective membership interests in Greyhawke (the "Distribution"). Mr. Plaumann holds a 50% ownership interest in Greyhawke and, as a result, received 5,862 shares in the Distribution. Mr. Plaumann is the trustee of the MS Trust. Mr. Plaumann, however, is not a beneficiary of the MS Trust, and disclaims any pecuniary interest in the 5,862 shares distributed by Greyhawke to the MS Trust in the Distribution. The Distribution did not involve a purchase or a sale of securities or any additional consideration, and did not result in a change in Mr. Plaumann's pecuniary interest in the shares.

F1 · balance_after: These shares were distributed by Greyhawke Capital Advisors LLC ("Greyhawke") in a partial in-kind distribution to Mr. Plaumann and the Martin and Selma Rosen GST Trust FBO Robert Rosen and Descendants U/A December 15, 2015 (the "MS Trust") proportionate to their respective membership interests in Greyhawke (the "Distribution"). Mr. Plaumann holds a 50% ownership interest in Greyhawke and, as a result, received 5,862 shares in the Distribution. Mr. Plaumann is the trustee of the MS Trust. Mr. Plaumann, however, is not a beneficiary of the MS Trust, and disclaims any pecuniary interest in the 5,862 shares distributed by Greyhawke to the MS Trust in the Distribution. The Distribution did not involve a purchase or a sale of securities or any additional consideration, and did not result in a change in Mr. Plaumann's pecuniary interest in the shares.

SEC source: 0001539838-24-000206 · wk-form4_1731622466.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · By Greyhawke Capital Advisors LLC

Disclosed balance after: 9,476

F1 · shares: These shares were distributed by Greyhawke Capital Advisors LLC ("Greyhawke") in a partial in-kind distribution to Mr. Plaumann and the Martin and Selma Rosen GST Trust FBO Robert Rosen and Descendants U/A December 15, 2015 (the "MS Trust") proportionate to their respective membership interests in Greyhawke (the "Distribution"). Mr. Plaumann holds a 50% ownership interest in Greyhawke and, as a result, received 5,862 shares in the Distribution. Mr. Plaumann is the trustee of the MS Trust. Mr. Plaumann, however, is not a beneficiary of the MS Trust, and disclaims any pecuniary interest in the 5,862 shares distributed by Greyhawke to the MS Trust in the Distribution. The Distribution did not involve a purchase or a sale of securities or any additional consideration, and did not result in a change in Mr. Plaumann's pecuniary interest in the shares.

F2 · ownership.direct: The remaining shares held by Greyhawke were previously assigned by Mr. Plaumann to Greyhawke under the terms of his employment with Greyhawke. As a managing member of Greyhawke and a holder of a 50% membership interest therein, Mr. Plaumann may be deemed to have a pecuniary interest in the securities held by Greyhawke.

SEC source: 0001539838-24-000132 · wk-form4_1718049866.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · By Greyhawke Capital Advisors LLC

Disclosed balance after: 21,200

F1 · shares: These securities are restricted stock units, each representing a contingent right to receive one share of common stock, par value $0.01 per share, of the issuer. These restricted stock units were granted to Mr. Plaumann as an annual non-employee director grant under the issuer's equity incentive plan and will vest on the earlier of the one-year anniversary of the date of grant and the date of the 2025 annual meeting of stockholders of the issuer.

F2 · ownership.nature: These shares have been assigned by Mr. Plaumann to Greyhawke Capital Advisors LLC ("Greyhawke"), under the terms of his employment with Greyhawke. Mr. Plaumann is a managing member of Greyhawke. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

SEC source: 0001539838-23-000083 · wk-form4_1686600304.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · By Greyhawke Capital Advisors LLC

Disclosed balance after: 20,165

F1 · shares: These securities are restricted stock units, each representing a contingent right to receive one share of common stock, par value $0.01 per share, of the issuer. These restricted stock units were granted to Mr. Plaumann as an annual non-employee director grant under the issuer's equity incentive plan and will vest on the earlier of the one-year anniversary of the date of grant and the date of the 2024 annual meeting of stockholders of the issuer.

F2 · ownership.nature: These shares have been assigned by Mr. Plaumann to Greyhawke Capital Advisors LLC ("Greyhawke"), under the terms of his employment with Greyhawke. Mr. Plaumann is a managing member of Greyhawke. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

SEC source: 0001539838-22-000097 · wf-form4_165515743784644.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By Greyhawke Capital Advisors LLC

Disclosed balance after: 18,638

F1 · shares: These securities are restricted stock units, each representing a contingent right to receive one share of common stock, par value $0.01 per share, of the issuer. These restricted stock units were granted to Mr. Plaumann as an annual non-employee director grant under the issuer's equity incentive plan and will vest on the earlier of the one-year anniversary of the date of grant and the date of the 2023 annual meeting of stockholders of the issuer.

F2 · ownership.nature: These shares have been assigned by Mr. Plaumann to Greyhawke Capital Advisors LLC ("Greyhawke"), under the terms of his employment with Greyhawke. Mr. Plaumann is a managing member of Greyhawke. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

SEC source: 0001539838-21-000090 · wf-form4_162309992865853.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By Greyhawke Capital Advisors LLC

Disclosed balance after: 17,364

F1 · shares: These securities are restricted stock units, each representing a contingent right to receive one share of common stock, par value $0.01 per share, of the issuer. These restricted stock units were granted to Mr. Plaumann as an annual non-employee director grant under the issuer's equity incentive plan and will vest on the earlier of the one-year anniversary of the date of grant and the date of the 2022 annual meeting of stockholders of the issuer.

F2 · ownership.nature: These shares have been assigned by Mr. Plaumann to Greyhawke Capital Advisors LLC ("Greyhawke"), under the terms of his employment with Greyhawke. Mr. Plaumann is a managing member of Greyhawke. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

SEC source: 0001539838-20-000077 · wf-form4_159139254420945.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By Greyhawke Capital Advisors LLC

Disclosed balance after: 14,929

F1 · shares: These securities are restricted stock units, each representing a contingent right to receive one share of common stock, par value $0.01 per share, of the issuer. These restricted stock units were granted to Mr. Plaumann as an annual non-employee director grant under the issuer's equity incentive plan and will vest on the earlier of the one-year anniversary of the date of grant and the date of the 2021 annual meeting of stockholders of the issuer.

F2 · ownership.nature: These shares have been assigned by Mr. Plaumann to Greyhawke Capital Advisors LLC ("Greyhawke"), under the terms of his employment with Greyhawke. Mr. Plaumann is a managing member of Greyhawke. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

SEC source: 0001539838-19-000071 · wf-form4_156020423395222.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By Greyhawke Capital Advisors LLC

Disclosed balance after: 11,964

F1 · shares: These securities are restricted stock units, each representing a contingent right to receive one share of common stock, par value $0.01 per share, of the issuer. These restricted stock units were granted to Mr. Plaumann as an annual non-employee director grant under the issuer's equity incentive plan and will vest on the earlier of the one-year anniversary of the date of grant and the date of the 2020 annual meeting of stockholders of the issuer.

F2 · ownership.direct: These shares have been assigned by Mr. Plaumann to Greyhawke Capital Advisors LLC ("Greyhawke"), under the terms of his employment with Greyhawke. Mr. Plaumann is a managing member of Greyhawke. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

F2 · ownership.nature: These shares have been assigned by Mr. Plaumann to Greyhawke Capital Advisors LLC ("Greyhawke"), under the terms of his employment with Greyhawke. Mr. Plaumann is a managing member of Greyhawke. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

SEC source: 0001539838-18-000070 · wf-form4_152875064910894.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By Greyhawke Capital Advisors LLC

Disclosed balance after: 10,134

F1 · shares: These securities are restricted stock units, each representing a contingent right to receive one share of common stock, par value $0.01 per share, of the issuer. These restricted stock units were granted under the issuer's 2016 Equity Incentive Plan and will vest on the earlier of the one-year anniversary of the date of grant and the date of the 2019 annual meeting of stockholders of the issuer.

F2 · ownership.direct: These shares have been assigned by Mr. Plaumann to Greyhawke Capital Advisors LLC ("Greyhawke"), under the terms of his employment with Greyhawke. Mr. Plaumann is a managing member of Greyhawke. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

F2 · ownership.nature: These shares have been assigned by Mr. Plaumann to Greyhawke Capital Advisors LLC ("Greyhawke"), under the terms of his employment with Greyhawke. Mr. Plaumann is a managing member of Greyhawke. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

SEC source: 0001539838-17-000095 · wf-form4_150005420265159.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By Greyhawke Capital Advisors LLC

Disclosed balance after: 8,560

F1 · shares: These securities are restricted stock units, each representing a contingent right to receive one share of common stock, par value $0.01 per share, of the issuer. These restricted stock units were granted under the issuer's 2016 Equity Incentive Plan and will vest on the earlier of the one-year anniversary of the date of grant and the date of the 2018 annual meeting of stockholders of the issuer.

F2 · ownership.direct: These shares are held by Greyhawke Capital Advisors LLC ("Greyhawke"), of which Mr. Plaumann is a managing member. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

F2 · ownership.nature: These shares are held by Greyhawke Capital Advisors LLC ("Greyhawke"), of which Mr. Plaumann is a managing member. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

SEC source: 0001539838-17-000082 · wf-form4_149572956339612.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By Greyhawke Capital Advisors LLC

Disclosed balance after: 6,505

F1 · ownership.direct: These shares are held by Greyhawke Capital Advisors LLC ("Greyhawke"), of which Mr. Plaumann is a managing member. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

F1 · ownership.nature: These shares are held by Greyhawke Capital Advisors LLC ("Greyhawke"), of which Mr. Plaumann is a managing member. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

SEC source: 0001539838-17-000023 · wf-form4_148772580806472.xml · nonDerivative · entry 1

Plaumann Mark Lawrence · CIK 0001290795 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By Greyhawke Capital Advisors LLC

Disclosed balance after: 7,505

F1 · price: The price reported in Column 4 is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from $107.35 per share to $107.38 per share, inclusive. The reporting person undertakes to provide to Diamondback Energy, Inc., any security holder of Diamondback Energy, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

F2 · ownership.direct: These shares are held by Greyhawke Capital Advisors LLC ("Greyhawke"), of which Mr. Plaumann is a managing member. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.

F2 · ownership.nature: These shares are held by Greyhawke Capital Advisors LLC ("Greyhawke"), of which Mr. Plaumann is a managing member. Mr. Plaumann holds a 50% ownership interest in Greyhawke and may be deemed to have a pecuniary interest in these securities.