AWM Investment Co. reports 214,776 NGS shares (NGS) ownership filing

Rhea-AI Filing Summary

NATURAL GAS SERVICES GROUP INC ownership filing shows 214,776 shares of common stock beneficially owned, representing 1.7% of the class. The filer, AWM Investment Company, Inc., reports sole voting and sole dispositive power over those shares as investment adviser to three funds, with holdings split among the Funds.

The filing names David M. Greenhouse and Adam C. Stettner as controlling principals and states the filer’s address and CUSIP 63886Q109.

Key Figures

Beneficial ownership: 214,776 shares Percent of class: 1.7% CAYMAN shares: 45,560 shares +3 more

6 metrics

Beneficial ownership 214,776 shares reported in Schedule 13G/A amendment

Percent of class 1.7% percent of common stock reported beneficially owned

CAYMAN shares 45,560 shares held by Special Situations Cayman Fund (as reported)

SSFQP shares 145,420 shares held by Special Situations Fund III QP (as reported)

SSPE shares 23,796 shares held by Special Situations Private Equity Fund (as reported)

CUSIP 63886Q109 Common Stock, Par Value $0.01

Key Terms

beneficially owned, sole dispositive power, Schedule 13G/A, investment adviser

4 terms

beneficially owned regulatory

"Amount beneficially owned: 214,776"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

sole dispositive power regulatory

"Sole power to dispose or to direct the disposition"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

Schedule 13G/A regulatory

"(Amendment No. 2 ) NATURAL GAS SERVICES GROUP INC"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

investment adviser financial

"AWM Investment Company, Inc., which is the investment adviser to Special Situations"

An investment adviser is a person or firm that professionally manages money and gives recommendations about buying, selling, or holding investments. Like a financial coach or guide, they have a legal duty to act in a client's best financial interest, so their advice, fees and potential conflicts can directly affect returns and risk — making their role important for investors who want informed, accountable help with portfolios.

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

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Accepted by SEC EDGAR 05/04/2026 - 07:15 PM Learn about SEC filing dates

FAQ

What stake does AWM report in NATURAL GAS SERVICES GROUP (NGS)?

AWM reports beneficial ownership of 214,776 shares, or 1.7%. The shares are held through three funds advised by AWM: Special Situations Cayman Fund, Special Situations Fund III QP, and Special Situations Private Equity Fund.

Who holds voting and investment power over the reported NGS shares?

AWM Investment Company, Inc. holds sole voting and dispositive power for the 214,776 shares as investment adviser to the three named Funds. David M. Greenhouse and Adam C. Stettner are identified as controlling principals.

How are the 214,776 NGS shares allocated among the funds?

The filing breaks the shares down as 45,560; 145,420; and 23,796. Those amounts correspond to holdings by Special Situations Cayman Fund, Special Situations Fund III QP, and Special Situations Private Equity Fund, respectively.

Does this Schedule 13G/A indicate AWM intends to exceed 5% ownership in NGS?

No—this filing states ownership of 1.7%. Item 5 explicitly notes "Ownership of 5 percent or less of a class," indicating the reported position remains below the 5% threshold.

Who signed the amended Schedule 13G/A for these NGS holdings?

Adam Stettner signed as Executive Vice President. The signature block in the amendment is dated 05/04/2026 and lists AWM’s New York business address.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 2)

NATURAL GAS SERVICES GROUP INC

(Name of Issuer)

Common Stock, Par Value $0.01

(Title of Class of Securities)

63886Q109

(CUSIP Number)

03/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 63886Q109

1

Names of Reporting Persons

AWM Investment Company, Inc.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 214,776.00
6	Shared Voting Power
7	Sole Dispositive Power 214,776.00
8	Shared Dispositive Power

9

Aggregate Amount Beneficially Owned by Each Reporting Person

214,776.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

1.7 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Cayman Fund, L.P. (CAYMAN), Special Situations Fund III QP, L.P. (SSFQP) and Special Situations Private Equity Fund, L.P. (SSPE). (CAYMAN, SSFQP and SSPE will hereafter be referred to as the Funds). As the investment adviser to the Funds, AWM holds sole voting and investment power over 45,560 shares of Common Stock of the Issuer (the Shares) held by CAYMAN, 145,420 Shares held by SSFQP, 23,796 Shares held by SSPE.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: NATURAL GAS SERVICES GROUP INC
(b)	Address of issuer's principal executive offices: 404 VETERANS AIRPARK LANE, SUITE 300, MIDLAND, TEXAS, 79705
Item 2.
(a)	Name of person filing: The person filing this report is AWM Investment Company, Inc., a Delaware corporation (AWM), which is the investment adviser to Special Situations Cayman Fund, L.P., a Cayman Islands Limited Partnership (CAYMAN), Special Situations Fund III QP, L.P., a Delaware limited partnership (SSFQP) and Special Situations Private Equity Fund, L.P., a Delaware limited partnership (SSPE), (CAYMAN, SSFQP and SSPE, will hereafter be referred to as the Funds). The principal business of each Fund is to invest in equity and equity-related securities and other securities of any kind or nature. David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are members of: SSCayman, L.L.C., a Delaware limited liability company (SSCAY), the general partner of CAYMAN. Greenhouse and Stettner are members of MGP Advisers Limited Partnership, a Delaware limited partnership (MGP), the general partner of SSFQP; MG Advisers, L.L.C., a New York limited liability company (MG), the general partner of SSPE. Greenhouse and Stettner are also controlling principals of AWM.
(b)	Address or principal business office or, if none, residence: 527 Madison Avenue, Suite 2600 New York, NY 10022
(c)	Citizenship: AWM is a Delaware Corporation
(d)	Title of class of securities: Common Stock, Par Value $0.01
(e)	CUSIP No.: 63886Q109
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 214,776
(b)	Percent of class: 1.7 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: AWM is the investment adviser to each of the Funds. As the investment adviser to the Funds, AWM holds sole voting power over 45,560 shares of common stock of the Issuer (the Shares) held by CAYMAN, 145,420 Shares held by SSFQP and 23,796 Shares held by SSPE. Greenhouse and Stettner are members of: SSCAY, the general partner of CAYMAN. Greenhouse and Stettner are members of MGP, the general partner of SSFQP; MG, the general partner of SSPE. Greenhouse and Stettner are also controlling principals of AWM.
	(ii) Shared power to vote or to direct the vote:
	(iii) Sole power to dispose or to direct the disposition of: AWM is the investment adviser to each of the Funds. As the investment adviser to the Funds, AWM holds sole investment power over 45,560 shares of common stock of the Issuer (the Shares) held by CAYMAN, 145,420 Shares held by SSFQP and 23,796 Shares held by SSPE. Greenhouse and Stettner are members of: SSCAY, the general partner of CAYMAN. Greenhouse and Stettner are members of MGP, the general partner of SSFQP; MG, the general partner of SSPE. Greenhouse and Stettner are also controlling principals of AWM.
	(iv) Shared power to dispose or to direct the disposition of:
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

AWM Investment Company, Inc.

Signature:	Adam Stettner
Name/Title:	Executive Vice President
Date:	05/04/2026