[Form 4] Arq, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Arq, Inc. Chief Executive Officer Robert E. Rasmus reported a routine tax-withholding share disposition tied to equity compensation. On March 23, 2026, 845 shares of common stock were withheld at $2.27 per share to satisfy tax obligations from vesting restricted stock awards.

Following this withholding, he directly holds 479,937 common shares. Additional indirect holdings are reported as 70,718 shares through RER Investments LLC and 527,779 shares through RER Legacy Investments II LLC, where he is the ultimate control person but disclaims beneficial ownership beyond his pecuniary interest.

Insights

Corporate governance analyst

Routine tax withholding on vested stock, not an open-market sale.

The filing shows Arq CEO Robert E. Rasmus had 845 common shares withheld at $2.27 per share on March 23, 2026. Footnotes explain this was to cover tax obligations from vesting restricted stock awards, a standard administrative mechanism.

This F-code transaction is classified as a tax-withholding disposition rather than a discretionary market sale, so it carries weak signaling value about his view of the stock. After the event he continues to hold a substantial position, including 479,937 shares directly and indirect interests via RER Investments LLC and RER Legacy Investments II LLC.

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^*

Rasmus Robert E.

(Last) (First) (Middle)

C/O ARQ, INC.

8051 E MAPLEWOOD AVE STE 210

(Street)

GREENWOOD VILLAGE COLORADO 80111

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Arq, Inc. [ ARQ ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/23/2026

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	03/23/2026		F		845(1)	D	$2.27	479,937	D
Common Stock								70,718	I	By RER Investments LLC(2)
Common Stock								527,779	I	By RER Legacy Investments II LLC.(3)

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. Reflects the withholding of shares of the Issuer's common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock awards ("RSAs") on March 23, 2026.

2. The shares of Common Stock reported on this row are held by RER Investments LLC ("RER Investments"). Mr. Rasmus, the Chief Executive Officer and a Director of the Issuer, is the ultimate control person of RER Investments, and an indirect beneficial owner of these shares. Mr. Rasmus disclaims beneficial ownership of these shares except to the extent of his pecuniary interest therein.

3. The shares of Common Stock reported on this row are held by RER Legacy Investments II LLC ("RER Legacy"). Mr. Rasmus, the Chief Executive Officer and a Director of the Issuer, is the ultimate control person of RER Legacy, and an indirect beneficial owner of these shares. Mr. Rasmus disclaims beneficial ownership of these shares except to the extent of his pecuniary interest therein.

Remarks:

	/s/ Robert E. Rasmus	03/25/2026
	** 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)

FAQ

What insider transaction did Arq (ARQ) report for CEO Robert E. Rasmus?

Arq reported that CEO Robert E. Rasmus had 845 shares of common stock withheld at $2.27 per share. This covered tax obligations related to the vesting of restricted stock awards on March 23, 2026, and was not an open-market sale or purchase.

Was the Arq (ARQ) CEO’s Form 4 transaction a sale of shares in the market?

No, the Form 4 shows a tax-withholding disposition of 845 shares at $2.27, not an open-market sale. The shares were withheld to satisfy tax liabilities arising from vesting restricted stock awards on March 23, 2026, a common administrative equity-compensation practice.

How many Arq (ARQ) shares does CEO Robert E. Rasmus hold after this transaction?

After the tax withholding, Robert E. Rasmus directly holds 479,937 shares of Arq common stock. The filing also reports 70,718 shares held indirectly through RER Investments LLC and 527,779 shares through RER Legacy Investments II LLC, where he is the ultimate control person.

What do the indirect Arq (ARQ) holdings through RER Investments LLC represent?

The Form 4 reports 70,718 Arq common shares held by RER Investments LLC. Rasmus is the ultimate control person and an indirect beneficial owner but disclaims beneficial ownership beyond his pecuniary interest, meaning his economic stake is limited to the portion he effectively owns.

What is RER Legacy Investments II LLC’s relationship to Arq (ARQ) CEO share ownership?

RER Legacy Investments II LLC holds 527,779 Arq common shares according to the filing. Robert E. Rasmus is its ultimate control person and an indirect beneficial owner, while disclaiming beneficial ownership except to the extent of his pecuniary interest in that entity’s holdings.

How significant is the 845-share tax withholding for Arq (ARQ) CEO’s overall position?

The 845-share tax withholding is small relative to Rasmus’s reported holdings. He still owns 479,937 shares directly, plus indirect interests via RER Investments LLC and RER Legacy Investments II LLC, so the transaction appears routine rather than a major change in exposure.