Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ Quarterly report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for the quarterly period ended July 4, 2021 or ☐ Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for the transition period from to Commission file number: 1-13703 Six Flags Entertainment Corporation (Exact Name of Registrant as Specified in Its Charter) Delaware (State or Other Ju ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ Quarterly report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for the quarterly period ended April 4, 2021 or ☐ Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for the transition period from to Commission file number: 1-13703 Six Flags Entertainment Corporation (Exact Name of Registrant as Specified in Its Charter) Title of each class Tradin ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ Annual Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for the fiscal year ended December 31, 2020 ☐ Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the transition period from to Commission File Number: 1-13703 SIX FLAGS ENTERTAINMENT CORPORATION Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in ...