NINE ENERGY SERVICE, INC. reported that CastleKnight-related reporting persons beneficially own 1,157,943 shares of common stock, representing 8.3% of the class as of 03/31/2026. The holdings are reported as shared voting and dispositive power under a joint filing by CastleKnight entities and Aaron Weitman.
Positive
None.
Negative
None.
Insights
Large passive stake disclosed by CastleKnight group, shown as shared control.
The filing lists 1,157,943 shares (8.3%) held with shared voting and dispositive power across CastleKnight Master Fund LP, related GP/management entities, Weitman Capital LLC, and Aaron Weitman. The schedule is a consolidation of related entities asserting shared control.
Practical implications depend on whether this stake is passive; the report follows Schedule 13G presentation. Subsequent disclosures could clarify any change to active investor status.
Shared voting/dispositive power implies coordinated influence rather than sole control.
All reporting persons list zero sole voting/dispositive power and identical shared power counts, indicating coordinated authority among affiliated vehicles and an individual manager. Signatures include a standard disclaimer of beneficial ownership to the extent of pecuniary interest.
Watch for amendments or a Schedule 13D if the group moves to active acquisition or seeks change in corporate control.
Key Figures
Reported shares beneficially owned:1,157,943 sharesPercent of class:8.3%Form type:Schedule 13G+3 more
6 metrics
Reported shares beneficially owned1,157,943 sharesAmount beneficially owned as of 03/31/2026
Percent of class8.3%Percent of common stock outstanding as reported
Form typeSchedule 13GFiling type for passive/beneficial ownership disclosure
CUSIP65441V200Nine Energy Service common stock identifier
Ownership reporting date03/31/2026As-of date for ownership amounts
Signature date04/09/2026Date the Schedule 13G was signed by reporting persons
"Item 1. (a) Name of issuer: NINE ENERGY SERVICE, INC."
A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.
Shared dispositive powerregulatory
"Shared Dispositive Power 1,157,943.00"
Beneficially ownedfinancial
"Amount beneficially owned: CastleKnight Master Fund LP - 1,157,943"
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.
CastleKnight-related reporting persons report 1,157,943 shares, equal to 8.3% of NINE ENERGY SERVICE common stock as of 03/31/2026. The amount is shown as shared voting and shared dispositive power among affiliated entities and Aaron Weitman.
Who are the filing parties for the 13G on NINEQ?
The filing names CastleKnight Master Fund LP, CastleKnight Fund GP LLC, CastleKnight Management LP, CastleKnight Management GP LLC, Weitman Capital LLC, and Aaron Weitman. Addresses and jurisdictions are provided in the filing text for each reporting person.
What voting and disposition rights are reported?
Each reporting person reports 0 sole voting/dispositive power and 1,157,943 shares of shared voting and shared dispositive power. That indicates coordinated authority rather than individual sole control over the reported shares.
When was the ownership reported and when was the form signed?
The ownership position is reported as of 03/31/2026. The signature block shows execution dates of 04/09/2026 by Aaron Weitman and affiliated entities as managers and signatories for the filing.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
NINE ENERGY SERVICE, INC.
(Name of Issuer)
Common Stock, par value $0.01 per share
(Title of Class of Securities)
65441V200
(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):
65441V200
1
Names of Reporting Persons
CastleKnight Master Fund LP
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
CAYMAN ISLANDS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
1,157,943.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,157,943.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,157,943.00
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)
8.3 %
12
Type of Reporting Person (See Instructions)
PN
SCHEDULE 13G
CUSIP Number(s):
65441V200
1
Names of Reporting Persons
CastleKnight Fund GP LLC
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
0.00
6
Shared Voting Power
1,157,943.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,157,943.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,157,943.00
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)
8.3 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
CUSIP Number(s):
65441V200
1
Names of Reporting Persons
CastleKnight Management LP
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
0.00
6
Shared Voting Power
1,157,943.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,157,943.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,157,943.00
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)
8.3 %
12
Type of Reporting Person (See Instructions)
IA, PN
SCHEDULE 13G
CUSIP Number(s):
65441V200
1
Names of Reporting Persons
CastleKnight Management GP LLC
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
0.00
6
Shared Voting Power
1,157,943.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,157,943.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,157,943.00
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)
8.3 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
CUSIP Number(s):
65441V200
1
Names of Reporting Persons
Weitman Capital LLC
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
NEW JERSEY
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
1,157,943.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,157,943.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,157,943.00
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)
8.3 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
CUSIP Number(s):
65441V200
1
Names of Reporting Persons
Aaron Weitman
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
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
1,157,943.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,157,943.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,157,943.00
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)
8.3 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
NINE ENERGY SERVICE, INC.
(b)
Address of issuer's principal executive offices:
2001 Kirby Drive, Suite 200, Houston, Texas 77019
Item 2.
(a)
Name of person filing:
CastleKnight Master Fund LP
CastleKnight Fund GP LLC
CastleKnight Management LP
CastleKnight Management GP LLC
Weitman Capital LLC
Aaron Weitman
(b)
Address or principal business office or, if none, residence:
CastleKnight Master Fund LP
Maples Corporate Services Limited
P.O. Box 309
Ugland House
Grand Cayman KY1-1104
Cayman Islands
CastleKnight Fund GP LLC
888 Seventh Avenue, 24th Floor
New York, New York 10019
United States of America
CastleKnight Management LP
888 Seventh Avenue, 24th Floor
New York, New York 10019
United States of America
CastleKnight Management GP LLC
888 Seventh Avenue, 24th Floor
New York, New York 10019
United States of America
Weitman Capital LLC
c/o Aaron Weitman
c/o CastleKnight Management LP
888 Seventh Avenue, 24th Floor
New York, New York 10019
United States of America
Aaron Weitman
c/o CastleKnight Management LP
888 Seventh Avenue, 24th Floor
New York, New York 10019
United States of America
(c)
Citizenship:
CastleKnight Master Fund LP - Cayman Islands
CastleKnight Fund GP LLC - Delaware
CastleKnight Management LP - Delaware
CastleKnight Management GP LLC - Delaware
Weitman Capital LLC - New Jersey
Aaron Weitman - United States
(d)
Title of class of securities:
Common Stock, par value $0.01 per share
(e)
CUSIP Number(s):
65441V200
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:
CastleKnight Master Fund LP - 1,157,943
CastleKnight Fund GP LLC - 1,157,943
CastleKnight Management LP - 1,157,943
CastleKnight Management GP LLC - 1,157,943
Weitman Capital LLC - 1,157,943
Aaron Weitman - 1,157,943
(b)
Percent of class:
CastleKnight Master Fund LP - 8.3%
CastleKnight Fund GP LLC - 8.3%
CastleKnight Management LP - 8.3%
CastleKnight Management GP LLC - 8.3%
Weitman Capital LLC - 8.3%
Aaron Weitman - 8.3%
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
CastleKnight Master Fund LP - 0
CastleKnight Fund GP LLC - 0
CastleKnight Management LP - 0
CastleKnight Management GP LLC - 0
Weitman Capital LLC - 0
Aaron Weitman - 0
(ii) Shared power to vote or to direct the vote:
CastleKnight Master Fund LP - 1,157,943
CastleKnight Fund GP LLC - 1,157,943
CastleKnight Management LP - 1,157,943
CastleKnight Management GP LLC - 1,157,943
Weitman Capital LLC - 1,157,943
Aaron Weitman - 1,157,943
(iii) Sole power to dispose or to direct the disposition of:
CastleKnight Master Fund LP - 0
CastleKnight Fund GP LLC - 0
CastleKnight Management LP - 0
CastleKnight Management GP LLC - 0
Weitman Capital LLC - 0
Aaron Weitman - 0
(iv) Shared power to dispose or to direct the disposition of:
CastleKnight Master Fund LP - 1,157,943
CastleKnight Fund GP LLC - 1,157,943
CastleKnight Management LP - 1,157,943
CastleKnight Management GP LLC - 1,157,943
Weitman Capital LLC - 1,157,943
Aaron Weitman - 1,157,943
Item 5.
Ownership of 5 Percent or Less of a Class.
Not Applicable
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.
If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary.
Please see Exhibit B attached hereto.
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 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.
CastleKnight Master Fund LP
Signature:
By: CastleKnight Fund GP LLC, its general partner, By: Weitman Capital LLC, its managing member, By: /s/ Aaron Weitman
Name/Title:
Aaron Weitman/Manager
Date:
04/09/2026
CastleKnight Fund GP LLC
Signature:
By: Weitman Capital LLC, its managing member, By: /s/ Aaron Weitman
Name/Title:
Aaron Weitman/Manager
Date:
04/09/2026
CastleKnight Management LP
Signature:
By: CastleKnight Management GP LLC, its general partner, By: Weitman Capital LLC, its managing member, By: /s/ Aaron Weitman
Name/Title:
Aaron Weitman/Manager
Date:
04/09/2026
CastleKnight Management GP LLC
Signature:
By: Weitman Capital LLC, its managing member, By: /s/ Aaron Weitman
Name/Title:
Aaron Weitman/Manager
Date:
04/09/2026
Weitman Capital LLC
Signature:
/s/ Aaron Weitman
Name/Title:
Aaron Weitman/Manager
Date:
04/09/2026
Aaron Weitman
Signature:
/s/ Aaron Weitman
Name/Title:
Aaron Weitman
Date:
04/09/2026
Comments accompanying signature: * Each Reporting Person disclaims beneficial ownership of the reported securities except to the extent of his, her or its pecuniary interest therein, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.
Exhibit Information
Exhibit A - Joint Filing Agreement
Exhibit B - Control Person Identification
