# EDGAR Filing Document

**Accession Number:** 0000061227
**File Stem:** 0001085146-26-000289
**Filing Date:** 2026-3
**Character Count:** 11932
**Document Hash:** 7b622702fd290240467219b8126743c7
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001085146-26-000289.hdr.sgml**: 20260331

**ACCESSION NUMBER**: 0001085146-26-000289

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13G

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20260331

**DATE AS OF CHANGE**: 20260331

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Nine Energy Service, Inc.
- **CENTRAL INDEX KEY:** 0001532286
- **STANDARD INDUSTRIAL CLASSIFICATION:** OIL, GAS FIELD SERVICES, NBC [1389]
- **ORGANIZATION NAME:** 01 Energy & Transportation
- **EIN:** 800759121
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-90688
- **FILM NUMBER:** 26820187

**BUSINESS ADDRESS:**
- **STREET 1:** 2001 KIRBY DRIVE
- **STREET 2:** SUITE 200
- **CITY:** HOUSTON
- **STATE:** TX
- **ZIP:** 77019
- **BUSINESS PHONE:** (713) 227-7888

**MAIL ADDRESS:**
- **STREET 1:** 2001 KIRBY DRIVE
- **STREET 2:** SUITE 200
- **CITY:** HOUSTON
- **STATE:** TX
- **ZIP:** 77019

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** NSC-Tripoint, Inc.
- **DATE OF NAME CHANGE:** 20111007
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** MACKAY SHIELDS LLC
- **CENTRAL INDEX KEY:** 0000061227
- **STANDARD INDUSTRIAL CLASSIFICATION:** UNKNOWN SIC - 0000 [0000]

**ORGANIZATION NAME:**
- **EIN:** 134080466
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G

**BUSINESS ADDRESS:**
- **STREET 1:** 299 PARK AVENUE
- **STREET 2:** 32ND FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10171
- **BUSINESS PHONE:** 212-230-3811

**MAIL ADDRESS:**
- **STREET 1:** 299 PARK AVENUE
- **STREET 2:** 32ND FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10171

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MACKAY SHIELDS FINANCIAL CORP
- **DATE OF NAME CHANGE:** 19920929

### Attached PDF Documents

**Attachment 1:** `mackay_jfa033126.pdf`

_No text found in this document._

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

## SCHEDULE 13G

### Under the Securities Exchange Act of 1934

**Issuer:** Nine Energy Service, Inc.

**Title of Class of Securities:** Common Stock

**CUSIP Number:** —

**Date of Event Which Requires Filing of this Statement:** 03/05/2026

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

- [x] Rule 13d-1(b)

- [ ] Rule 13d-1(c)

- [ ] Rule 13d-1(d)

---

| 1. | Names of Reporting Persons<br>MacKay Shields LLC | Names of Reporting Persons<br>MacKay Shields LLC |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>DE | Citizenship or Place of Organization<br>DE |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>1662134.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>1662134.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1662134.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1662134.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>11.91% | Percent of Class Represented by Amount in Row (9)<br>11.91% |
| 12. | Type of Reporting Person (See Instructions)<br>IA | Type of Reporting Person (See Instructions)<br>IA |

**Comment for Type of Reporting Person:** The reporting persons are party to a voting agreement with the Issuer dated March 5, 2026. This agreement allows the reporting persons to vote up to 10% of the total voting power of all of the outstanding voting securities of the Company on such matter as of the applicable record date after giving effect to any other voting agreement between the Company and any of its shareholders. The percentage reported herein is calculated based on 13,950,000 shares of Common Stock outstanding as of March 5, 2026.

---

| 1. | Names of Reporting Persons<br>NYLI MacKay High Yield Corporate Bond Fund | Names of Reporting Persons<br>NYLI MacKay High Yield Corporate Bond Fund |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>MA | Citizenship or Place of Organization<br>MA |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>1404300.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>1404300.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1404300.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>1404300.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>10.07% | Percent of Class Represented by Amount in Row (9)<br>10.07% |
| 12. | Type of Reporting Person (See Instructions)<br>IV | Type of Reporting Person (See Instructions)<br>IV |

**Comment for Type of Reporting Person:** The reporting persons are party to a voting agreement with the Issuer dated March 5, 2026. This agreement allows the reporting persons to vote up to 10% of the total voting power of all of the outstanding voting securities of the Company on such matter as of the applicable record date after giving effect to any other voting agreement between the Company and any of its shareholders. The percentage reported herein is calculated based on 13,950,000 shares of Common Stock outstanding as of March 5, 2026.

---

**Item 1(a). Name of Issuer:**
Nine Energy Service, Inc.

**Item 1(b). Address of Issuer's Principal Executive Offices:**
2001 KIRBY DRIVE, SUITE 200, HOUSTON, 77019

**Item 2(a). Name of Person Filing:**
MacKay Shields LLC

NYLI MacKay High Yield Corporate Bond Fund

**Item 2(b). Address of Principal Business Office:**
299 PARK AVENUE
32ND FLOOR
New York, New York
10171

**Item 2(c). Citizenship:**
MacKay Shields LLC - Delaware

NYLI MacKay High Yield Corporate Bond Fund - Massachusetts

**Item 2(d). Title of Class of Securities:**
Common Stock

**Item 2(e). CUSIP Number:**
—

**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) [x] 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:**

MacKay Shields LLC - 1,662,134
NYLI MacKay High Yield Corporate Bond Fund - 1,404,300

**(b) Percent of class:**

21.98

**(c) Number of shares as to which the person has:**

**(i) Sole power to vote or to direct the vote:**

MacKay Shields LLC - 0
NYLI MacKay High Yield Corporate Bond Fund - 0

**(ii) Shared power to vote or to direct the vote:**

MacKay Shields LLC - 1,662,134
NYLI MacKay High Yield Corporate Bond Fund - 1,404,300

**(iii) Sole power to dispose or to direct the disposition of:**

MacKay Shields LLC - 0
NYLI MacKay High Yield Corporate Bond Fund - 0

**(iv) Shared power to dispose or to direct the disposition of:**

MacKay Shields LLC - 1,662,134
NYLI MacKay High Yield Corporate Bond Fund - 1,404,300

**Item 5. Ownership of Five Percent or Less of a Class.**

[x] If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following.

**Item 6. Ownership of More than 5 Percent on Behalf of Another Person.**

MacKay Shields LLC, an investment advisor registered under Section 203 of the Investment Advisors Act of 1940 is deemed to be the beneficial owner of 1,662,134 shares of the 11.91% of the Common Stock believed to be outstanding as a result of acting as investment adviser to various clients. All calculations of percentage ownership are based on a total of 13,950,000 shares of Common Stock issued and outstanding as of March 5, 2026.

The NYLI MacKay High Yield Corporate Bond Fund, a registered investment company for which MacKay Shields acts as a sub investment adviser, may be deemed to beneficially own 10.07% of the outstanding common stock of the Company. New York Life Investment Management LLC and indirect wholly owned subsidiary of New York Life and an affiliate of MacKay Shields LLC, is the manager of the NYLI MacKay High Yield Corporate Bond Fund.

**Item 7. Identification and Classification of the Subsidiary**

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. Certification:**

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.

**MacKay Shields LLC**

**Date:** 03/31/2026

**By:** Chris Fitzgerald

**Name & Title:** Chief Compliance Officer

**NYLI MacKay High Yield Corporate Bond Fund**

**Date:** 03/31/2026

**By:** Chris Fitzgerald

**Name & Title:** Chief Compliance Officer