# EDGAR Filing Document

**Accession Number:** 0001854440
**File Stem:** 0000935836-25-000523
**Filing Date:** 2025-8
**Character Count:** 20186
**Document Hash:** 5385c57d1971e27f050016bc8c2bf326
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000935836-25-000523.hdr.sgml**: 20250814

**ACCESSION NUMBER**: 0000935836-25-000523

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13G/A

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20250814

**DATE AS OF CHANGE**: 20250814

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Six Flags Entertainment Corporation/NEW
- **CENTRAL INDEX KEY:** 0001999001
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-AMUSEMENT & RECREATION SERVICES [7900]
- **ORGANIZATION NAME:** 07 Trade & Services
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-94553
- **FILM NUMBER:** 251217065

**BUSINESS ADDRESS:**
- **STREET 1:** 8701 RED OAK BLVD.
- **CITY:** CHARLOTTE
- **STATE:** NC
- **ZIP:** 28217
- **BUSINESS PHONE:** (419) 626-0830

**MAIL ADDRESS:**
- **STREET 1:** 8701 RED OAK BLVD.
- **CITY:** CHARLOTTE
- **STATE:** NC
- **ZIP:** 28217

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** CopperSteel HoldCo, Inc.
- **DATE OF NAME CHANGE:** 20231027
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** DARLINGTON PARTNERS CAPITAL MANAGEMENT, LP
- **CENTRAL INDEX KEY:** 0001854440

**ORGANIZATION NAME:**
- **EIN:** 851409925
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

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

**BUSINESS ADDRESS:**
- **STREET 1:** 300 DRAKES LANDING ROAD
- **STREET 2:** SUITE 290
- **CITY:** GREENBRAE
- **STATE:** CA
- **ZIP:** 94904
- **BUSINESS PHONE:** 4154644648

**MAIL ADDRESS:**
- **STREET 1:** 300 DRAKES LANDING ROAD
- **STREET 2:** SUITE 290
- **CITY:** GREENBRAE
- **STATE:** CA
- **ZIP:** 94904

## Ex-99

EXHIBIT 99.1

AGREEMENT REGARDING JOINT FILING

OF STATEMENT ON SCHEDULE 13D OR 13G

The undersigned agree to file jointly with the Securities and Exchange Commission (the "SEC") any and all statements on Schedule 13D or Schedule 13G and Forms 3, 4 and 5 (and any amendments or supplements thereto) required under section 13(d) or section 16(a) of the Securities Exchange Act of 1934, as amended, in connection with purchases and sales by the undersigned of securities of any issuer, until such time as the undersigned file with the SEC a statement terminating this Agreement Regarding Joint Filing of Statement on Schedule 13D or 13G. For that purpose, the undersigned hereby constitute and appoint Darlington Partners Capital Management, LP, a Delaware limited partnership, as their true and lawful agent and attorney-in-fact, with full power and authority for and on behalf of the undersigned to prepare or cause to be prepared, sign, file with the SEC and furnish to any other person all certificates, instruments, agreements and documents necessary to comply with section 13(d) and section 16(a) of the Securities Exchange Act of 1934, as amended, in connection with said purchases and sales, and to do and perform every act necessary and proper to be done incident to the exercise of the foregoing power, as fully as the undersigned might or could do if personally present, until such time as the undersigned file with the SEC a statement terminating this Agreement Regarding Joint Filing of Statement on Schedule 13D or 13G.

Dated: April 12, 2021

---

| | |
|:---|:---|
| &nbsp;&nbsp; **DARLINGTON PARTNERS CAPITAL MANAGEMENT, LP**<br>By: Darlington Partners GP, LLC,<br> General Partner<br>By: *<u>/s/ Scott W. Clark</u>*  <br> Scott W. Clark, Manager<br>| &nbsp;&nbsp; **DARLINGTON PARTNERS GP, LLC**<br>By: *<u>/s/ Scott W. Clark</u>* <br> Scott W. Clark, Manager<br>|
| &nbsp;&nbsp; *<u>/s/ Scott W. Clark</u>* <br> Scott W. Clark<br>| &nbsp;&nbsp; *<u>/s/ Ramsey B. Jishi</u>* <br> Ramsey B. Jishi<br>|
| &nbsp;&nbsp; **DARLINGTON PARTNERS, L.P.**<br>By: Darlington Partners GP, LLC,<br>By: *<u>/s/ Scott W. Clark</u>* <br> Scott W. Clark, Manager<br>|  |

---

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

## SCHEDULE 13G

### Under the Securities Exchange Act of 1934

**(Amendment No. 2)**

**Issuer:** Six Flags Entertainment Corporation/NEW

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

**CUSIP Number:** 83001C108

**Date of Event Which Requires Filing of this Statement:** 06/30/2025

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

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

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

- [ ] Rule 13d-1(d)

---

| 1. | Names of Reporting Persons<br>Darlington Partners Capital Management, LP | Names of Reporting Persons<br>Darlington Partners Capital Management, LP |
|:---|:---|:---|:---|
| 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>8700000.00 |
| 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>8700000.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>8700000.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>8700000.00 |
| 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>8.6% | Percent of Class Represented by Amount in Row (9)<br>8.6% |
| 12. | Type of Reporting Person (See Instructions)<br>IA, PN | Type of Reporting Person (See Instructions)<br>IA, PN |

**Comment for Type of Reporting Person:** Percentage calculated based on 101,101,235 shares of Common Stock outstanding on May 2, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 30, 2025.

---

| 1. | Names of Reporting Persons<br>Darlington Partners GP, LLC | Names of Reporting Persons<br>Darlington Partners GP, 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>8700000.00 |
| 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>8700000.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>8700000.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>8700000.00 |
| 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>8.6% | Percent of Class Represented by Amount in Row (9)<br>8.6% |
| 12. | Type of Reporting Person (See Instructions)<br>HC, OO | Type of Reporting Person (See Instructions)<br>HC, OO |

**Comment for Type of Reporting Person:** Percentage calculated based on 101,101,235 shares of Common Stock outstanding on May 2, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 30, 2025.

---

| 1. | Names of Reporting Persons<br>Darlington Partners, L.P. | Names of Reporting Persons<br>Darlington Partners, L.P. |
|:---|:---|:---|:---|
| 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>8700000.00 |
| 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>8700000.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>8700000.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>8700000.00 |
| 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>8.6% | Percent of Class Represented by Amount in Row (9)<br>8.6% |
| 12. | Type of Reporting Person (See Instructions)<br>PN | Type of Reporting Person (See Instructions)<br>PN |

**Comment for Type of Reporting Person:** Percentage calculated based on 101,101,235 shares of Common Stock outstanding on May 2, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 30, 2025.

---

| 1. | Names of Reporting Persons<br>Scott W. Clark | Names of Reporting Persons<br>Scott W. Clark |
|:---|:---|:---|:---|
| 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>X1 | Citizenship or Place of Organization<br>X1 |
| 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>8700000.00 |
| 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>8700000.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>8700000.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>8700000.00 |
| 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>8.6% | Percent of Class Represented by Amount in Row (9)<br>8.6% |
| 12. | Type of Reporting Person (See Instructions)<br>HC, IN | Type of Reporting Person (See Instructions)<br>HC, IN |

**Comment for Type of Reporting Person:** Percentage calculated based on 101,101,235 shares of Common Stock outstanding on May 2, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 30, 2025.

---

| 1. | Names of Reporting Persons<br>Ramsey B. Jishi | Names of Reporting Persons<br>Ramsey B. Jishi |
|:---|:---|:---|:---|
| 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>X1 | Citizenship or Place of Organization<br>X1 |
| 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>8700000.00 |
| 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>8700000.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>8700000.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>8700000.00 |
| 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>8.6% | Percent of Class Represented by Amount in Row (9)<br>8.6% |
| 12. | Type of Reporting Person (See Instructions)<br>HC, IN | Type of Reporting Person (See Instructions)<br>HC, IN |

**Comment for Type of Reporting Person:** Percentage calculated based on 101,101,235 shares of Common Stock outstanding on May 2, 2025, as reported in the Form 10-Q filed by the Issuer for the quarter ended March 30, 2025.

---

**Item 1(a). Name of Issuer:**
Six Flags Entertainment Corporation/NEW

**Item 1(b). Address of Issuer's Principal Executive Offices:**
8701 RED OAK BLVD. CHARLOTTE, NORTH CAROLINA 28217

**Item 2(a). Name of Person Filing:**
Darlington Partners Capital Management, LP, a Delaware limited partnership ("DPCM LP")

Darlington Partners GP, LLC, a Delaware limited liability company ("DP GP")

Darlington Partners, L.P., a Delaware limited Darlington ("Darlington")

Scott W. Clark

Ramsey B. Jishi

DPCM LP is the investment adviser of private investment funds, including Darlington (together, the "Funds").  DP GP is the general partner of DPCM LP and the Funds.  Mr. Clark and Mr. Jishi are the managers of DP GP.  The Filers are filing this Schedule 13G jointly but not as members of a group, and each disclaims membership in a group.  Each reporting person disclaims beneficial ownership of Common Stock except to the extent of that person's pecuniary interest therein.  In addition, the filing of this Schedule 13G on behalf of Darlington should not be construed as an admission that it is, and it disclaims that it is, a beneficial owner, as defined in Rule 13d-3 under the Act, of any Common Stock covered by this Schedule 13G.

**Item 2(b). Address of Principal Business Office:**
300 Drakes Landing Road, Suite 290, Greenbrae, CA 94904

**Item 2(c). Citizenship:**
See Item 4 of the cover sheet for each reporting person.

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

**Item 2(e). CUSIP Number:**
83001C108

**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) [x] 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:**

DPCM LP:  8,700,000
DP GP:  8,700,000
Darlington:  8,700,000
Scott W. Clark:  8,700,000
Ramsey B. Jishi:  8,700,000

**(b) Percent of class:**

DPCM LP:  8.6%
DP GP:  8.6%
Darlington:  8.6%
Scott W. Clark:  8.6%
Ramsey B. Jishi:  8.6%

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

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

DPCM LP:  0
DP GP:  0
Darlington:  0
Scott W. Clark:  0
Ramsey B. Jishi:  0

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

DPCM LP:  8,700,000
DP GP:  8,700,000
Darlington:  8,700,000
Scott W. Clark:  8,700,000
Ramsey B. Jishi:  8,700,000

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

DPCM LP:  0
DP GP:  0
Darlington:  0
Scott W. Clark:  0
Ramsey B. Jishi:  0

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

DPCM LP:  8,700,000
DP GP:  8,700,000
Darlington:  8,700,000
Scott W. Clark:  8,700,000
Ramsey B. Jishi:  8,700,000

**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.**

DPCM LP's clients, including Darlington, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Stock.  No individual client's holdings of the Stock, other than those of Darlington, are more than five percent of the outstanding Stock.

**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.

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.

**Darlington Partners Capital Management, LP**

**Date:** 08/14/2025

**By:** /s/ Scott W. Clark

**Name & Title:** Manager of Darlington Partners GP, LLC, general partner of Darlington Partners Capital Management, LP

**Darlington Partners GP, LLC**

**Date:** 08/14/2025

**By:** /s/ Scott W. Clark

**Name & Title:** Manager

**Darlington Partners, L.P.**

**Date:** 08/14/2025

**By:** /s/ Scott W. Clark

**Name & Title:** Manager of Darlington Partners GP, LLC, general partner of Darlington Partners, L.P.

**Scott W. Clark**

**Date:** 08/14/2025

**By:** /s/ Scott W. Clark

**Name & Title:** Reporting person

**Ramsey B. Jishi**

**Date:** 08/14/2025

**By:** /s/ Ramsey B. Jishi

**Name & Title:** Reporting person