As filed with the United States Securities and Exchange Commission on May 14, 2021

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

POST-EFFECTIVE AMENDMENT NO. 1 TO:

FORM S-8 REGISTRATION STATEMENT NO. 333-233507

FORM S-8 REGISTRATION STATEMENT NO. 333-206564

FORM S-8 REGISTRATION STATEMENT NO. 333-135728

FORM S-8 REGISTRATION STATEMENT NO. 333-129178

FORM S-8 REGISTRATION STATEMENT NO. 333-55738

FORM S-8 REGISTRATION STATEMENT NO. 33-85324

FORM S-8 REGISTRATION STATEMENT NO. 33-74098

FORM S-8 REGISTRATION STATEMENT NO. 33-68560

TO

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Gulfport Energy Corporation

(Exact name of registrant as specified in its charter)

Gulfport Energy Corporation 2019 Amended and Restated Stock Incentive Plan

Gulfport Energy Corporation 2013 Restated Stock Incentive Plan

Gulfport Energy Corporation 2005 Stock Incentive Plan

Gulfport Energy Corporation 1999 Stock Option Plan

(Full title of the plan)

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

DEREGISTRATION OF SECURITIES

These Post-Effective Amendments (the “Post-Effective Amendments”) are being filed by Gulfport Energy Corporation (the “Company”) to deregister all securities unsold under the following Registration Statements on Form S-8 (the “Registration Statements”) filed by the Company with the Securities and Exchange Commission (the “SEC”):

As previously disclosed, on November 13, 2020, the Company and certain of its subsidiaries (together with the Company, the “Debtors”) commenced voluntary cases (the “Chapter 11 Cases”) under chapter 11 of the United States Bankruptcy Code in the United States Bankruptcy Court for the Southern District of Texas. The Debtors’ Chapter 11 Cases are jointly administered under the caption In re Gulfport Energy Corporation, et al., Case No. 20-35562 (DRJ).

As a result of the Chapter 11 Cases, the Company has terminated all offerings of securities pursuant to the Registration Statements. In accordance with an undertaking made by the Company in the Registration Statements to remove from registration, by means of a post-effective amendment, any of the securities that had been registered for issuance that remain unsold at the termination of such offering, the Company hereby removes from registration by means of these Post-Effective Amendments all of such securities registered but unsold under the Registration Statements. The Registration Statements are hereby amended, as appropriate, to reflect the deregistration of such securities and the Company hereby terminates the effectiveness of each of the Registration Statements.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended (the “Act”), the registrant has duly caused these Post-Effective Amendments to the Registration Statements on Form S-8 to be signed on its behalf by the undersigned, thereunto duly authorized, in the city of Oklahoma City, State of Oklahoma, on May 14, 2021. No other person is required to sign these Post-Effective Amendments to the Registration Statements on Form S-8 in reliance upon Rule 478 under the Act.

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