Darlington Partners and related filers report shared beneficial ownership of 8,700,000 shares (8.5%) of Six Flags Entertainment Corporation common stock in an Amendment No. 4 to a Schedule 13G/A. The 8,700,000 shares are reported as held with shared voting and dispositive power across Darlington Partners Capital Management, Darlington Partners GP, LLC, Darlington Partners, L.P., and the reporting persons Scott W. Clark and Ramsey B. Jishi. The percentage is calculated using 101,987,541 shares outstanding as of March 27, 2026, as cited from the issuer's proxy statement filed April 9, 2026. The filing includes signed certifications that the holdings were not acquired to change or influence control.
Positive
None.
Negative
None.
Insights
Holders report an 8.5% shared stake with shared voting and dispositive power.
The filing records 8,700,000 shares held with shared voting and dispositive authority by Darlington-linked entities and two managers. This structure indicates control is exercised collectively through the partnership and GP rather than by a single individual.
Key dependencies include any amendments to the Schedule 13G/A position and disclosures in subsequent proxy filings; future filings will show whether the stake crosses thresholds triggering different reporting categories.
This is a disclosure of beneficial ownership, not an operational or financing event.
The statement ties the 8.5% figure to a specific outstanding-share base: 101,987,541 shares as of March 27, 2026, cited from the proxy statement. The filing includes customary disclaimers that the filers do not form a group and disclaim beneficial ownership beyond pecuniary interest.
Cash‑flow treatment or sale intent is not stated; subsequent filings would clarify any changes in position or plans.
Key Figures
Shares beneficially owned:8,700,000 sharesPercent of class:8.5%Shares outstanding used:101,987,541 shares+2 more
5 metrics
Shares beneficially owned8,700,000 sharesReported beneficial ownership by Darlington-related filers
Percent of class8.5%Calculated using shares outstanding as of <date>March 27, 2026</date>
Shares outstanding used101,987,541 sharesOutstanding share count referenced from the issuer's proxy statement filed April 9, 2026
Signature date<date>05/15/2026</date>Reported signature dates for the filing certifications
Key Terms
Schedule 13G/A, beneficial ownership, shared dispositive power
3 terms
Schedule 13G/Aregulatory
"Amendment No. 4 to Schedule 13G/A reporting beneficial ownership"
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.
beneficial ownershipfinancial
"Amount beneficially owned: DPCM LP: 8,700,000 (percent of class 8.5%)"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
shared dispositive powerregulatory
"Shared Dispositive Power 8,700,000.00 reported for each filing person"
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 4)
Six Flags Entertainment Corporation/NEW
(Name of Issuer)
Common Stock
(Title of Class of Securities)
83001C108
(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):
83001C108
1
Names of Reporting Persons
Darlington Partners Capital 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
8,700,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
8,700,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
8,700,000.00
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)
8.5 %
12
Type of Reporting Person (See Instructions)
IA, PN
Comment for Type of Reporting Person: Percentage calculated based on 101,987,541 shares of Common Stock outstanding on March 27, 2026, as reported in the proxy statement filed by the Issuer on April 9, 2026.
SCHEDULE 13G
CUSIP Number(s):
83001C108
1
Names of Reporting Persons
Darlington Partners 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
8,700,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
8,700,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
8,700,000.00
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)
8.5 %
12
Type of Reporting Person (See Instructions)
HC, OO
Comment for Type of Reporting Person: Percentage calculated based on 101,987,541 shares of Common Stock outstanding on March 27, 2026, as reported in the proxy statement filed by the Issuer on April 9, 2026.
SCHEDULE 13G
CUSIP Number(s):
83001C108
1
Names of Reporting Persons
Darlington Partners, L.P.
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
8,700,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
8,700,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
8,700,000.00
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)
8.5 %
12
Type of Reporting Person (See Instructions)
PN
Comment for Type of Reporting Person: Percentage calculated based on 101,987,541 shares of Common Stock outstanding on March 27, 2026, as reported in the proxy statement filed by the Issuer on April 9, 2026.
SCHEDULE 13G
CUSIP Number(s):
83001C108
1
Names of Reporting Persons
Scott W. Clark
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
8,700,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
8,700,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
8,700,000.00
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)
8.5 %
12
Type of Reporting Person (See Instructions)
HC, IN
Comment for Type of Reporting Person: Percentage calculated based on 101,987,541 shares of Common Stock outstanding on March 27, 2026, as reported in the proxy statement filed by the Issuer on April 9, 2026.
SCHEDULE 13G
CUSIP Number(s):
83001C108
1
Names of Reporting Persons
Ramsey B. Jishi
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
8,700,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
8,700,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
8,700,000.00
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)
8.5 %
12
Type of Reporting Person (See Instructions)
HC, IN
Comment for Type of Reporting Person: Percentage calculated based on 101,987,541 shares of Common Stock outstanding on March 27, 2026, as reported in the proxy statement filed by the Issuer on April 9, 2026.
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Six Flags Entertainment Corporation/NEW
(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.
(b)
Address or principal business office or, if none, residence:
300 Drakes Landing Road, Suite 290, Greenbrae, CA 94904
(c)
Citizenship:
See Item 4 of the cover sheet for each reporting person.
(d)
Title of class of securities:
Common Stock
(e)
CUSIP No.:
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)
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:
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: 8.5%
DP GP: 8.5%
Darlington: 8.5%
Scott W. Clark: 8.5%
Ramsey B. Jishi: 8.5%
(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 5 Percent or Less of a Class.
Not Applicable
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required.
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 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.
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
Signature:
/s/ Scott W. Clark
Name/Title:
Manager of Darlington Partners GP, LLC, general partner of Darlington Partners Capital Management, LP
Date:
05/15/2026
Darlington Partners GP, LLC
Signature:
/s/ Scott W. Clark
Name/Title:
Manager
Date:
05/15/2026
Darlington Partners, L.P.
Signature:
/s/ Scott W. Clark
Name/Title:
Manager of Darlington Partners GP, LLC, general partner of Darlington Partners, L.P.
Date:
05/15/2026
Scott W. Clark
Signature:
/s/ Scott W. Clark
Name/Title:
Reporting person
Date:
05/15/2026
Ramsey B. Jishi
Signature:
/s/ Ramsey B. Jishi
Name/Title:
Reporting person
Date:
05/15/2026
Exhibit Information
Exhibit 99.1 - Agreement Regarding Joint Filing of Statement on Schedule 13D or 13G
What stake does Darlington Partners report in Six Flags (FUN)?
Darlington reports 8,700,000 shares, equal to 8.5% of Six Flags common stock. The percentage is calculated using 101,987,541 shares outstanding as of March 27, 2026, per the issuer's proxy statement filed April 9, 2026.
Who specifically holds the reported Six Flags shares for Darlington?
The shares are reported as held by DPCM LP, Darlington Partners GP, LLC, Darlington Partners, L.P., Scott W. Clark, and Ramsey B. Jishi. All are disclosed as having shared voting and dispositive power over the 8,700,000 shares.
Does the filing say Darlington intends to change control of Six Flags?
No; the filers certify the securities were not acquired and are not held to change or influence control. The filing contains signed certifications stating no acquisition for control purposes.
On what date is the outstanding share base for the 8.5% stake measured?
The 8.5% calculation uses the outstanding share count of 101,987,541 shares as of March 27, 2026, which the filing cites from the issuer's proxy statement filed April 9, 2026.
Do the filers claim sole voting or dispositive power over the reported shares?
No; each reporting person discloses 0 sole voting power and 8,700,000 shared voting and dispositive power, indicating shared control rather than unilateral authority over votes or dispositions.
