Mammoth Energy director buys 5,000 TUSK shares

MAMMOTH ENERGY SERVICES, INC.

Rhea-AI Filing Summary

MAMMOTH ENERGY SERVICES, INC. (TUSK) director Mark Lawrence Plaumann purchased 5,000 shares of common stock on September 16, 2026 in an open-market transaction at a weighted average price of $3.00 per share. Following this purchase, he beneficially owns 5,000 shares, including 2,100 shares in a Roth IRA and 2,900 shares in a traditional IRA held for his benefit. No Rule 10b5-1 trading plan is reported.

Insider Trade Summary

Net Buyer: 5,000 shares

Net Buy 1 txn

Insider Plaumann Mark Lawrence

Role Director

Bought 5,000 shs ($15K)

Type	Security	Shares	Price	Value
Purchase	Common Stock F1, F2	5,000	$3.00	$15K

Holdings After Transaction: Common Stock — 5,000 shares (Direct)

Footnotes (2)

1. F1. 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.
2. F2. 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.

Key Figures

Shares purchased: 5,000 shares Weighted average purchase price: $3.00 per share Shares owned after transaction: 5,000 shares +2 more

5 metrics

Shares purchased 5,000 shares Open-market purchase on September 16, 2026 by director

Weighted average purchase price $3.00 per share Average price across multiple purchase transactions on September 16, 2026

Shares owned after transaction 5,000 shares Total common stock beneficially owned by the director following the purchase

Roth IRA holdings 2,100 shares Portion of post-transaction holdings in a Roth IRA for the reporting person

Traditional IRA holdings 2,900 shares Portion of post-transaction holdings in a traditional IRA for the reporting person

Key Terms

weighted average purchase price, Roth IRA, traditional IRA

3 terms

weighted average purchase price financial

"The price reported in Column 4 is a weighted average purchase price."

The weighted average purchase price is the average cost per share you paid across multiple buys, calculated so larger purchases count more than smaller ones. Imagine buying apples at different prices: the overall price you effectively paid depends on how many apples you bought at each price. Investors use it to measure true cost basis, calculate gains or losses, decide when to sell, and manage taxes and portfolio performance.

Roth IRA financial

"2,100 shares are held in a Roth IRA and 2,900 shares are held"

A Roth IRA is a retirement savings account you fund with money that’s already been taxed, and withdrawals taken in retirement under the account rules are tax-free. It matters to investors because it shifts the tax bill to today instead of retirement, potentially increasing after-tax income later—think of it like paying for a lifetime subscription now so you can use it without extra charges in the future—helpful for long-term tax planning and flexibility.

traditional IRA financial

"2,100 shares are held in a Roth IRA and 2,900 shares are held"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did TUSK disclose in this Form 4?

The filing reports that director Mark Lawrence Plaumann purchased 5,000 shares of Mammoth Energy Services common stock on September 16, 2026 in an open-market transaction at a weighted average price of $3.00 per share.

How many TUSK shares does the director own after this transaction?

After the reported purchase, Mark Lawrence Plaumann beneficially owns 5,000 shares of Mammoth Energy Services common stock. Of these, 2,100 shares are held in a Roth IRA and 2,900 shares are held in a traditional IRA, each for his benefit.

At what price were the TUSK shares purchased by the director?

The reported price is a weighted average purchase price of $3.00 per share. The shares were bought in multiple transactions at prices within a range, with the weighted average of those trades reported as $3.00.

Was the TUSK insider purchase made under a Rule 10b5-1 trading plan?

No. The Form 4 indicates that the Rule 10b5-1 checkbox is not marked and the footnotes do not describe any such plan, so no Rule 10b5-1 trading plan is reported for this purchase.

How are the director’s TUSK shares held according to the Form 4?

According to a footnote, of the 5,000 shares reported, 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, reflecting retirement-account holdings.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/17/2026 - 04:51 PM Accepted by SEC EDGAR 09/17/2026 - 04:50 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Plaumann Mark Lawrence

(Last) (First) (Middle)

14201 CALIBER DRIVE

SUITE 300

(Street)

OKLAHOMA CITY OKLAHOMA 73134

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
MAMMOTH ENERGY SERVICES, INC. [ TUSK ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/16/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	09/16/2026		P		5,000	A	$3(1)	5,000(2)	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. 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.

2. 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.

Remarks:

	/s/ Mark Plaumann	09/17/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)