UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K/A

Amendment No. 1

For the fiscal year ended December 31, 2017

or

For the transition period from                      to                     

Commission File Number: 001-36511

Eclipse Resources Corporation

(Exact name of registrant as specified in its charter)

(814) 308-9754

(Registrant’s telephone number, including area code)

Securities Registered Pursuant to Section 12(b) of the Act:

Securities Registered Pursuant to Section 12(g) of the Act: None.

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ☐    No  ☒

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes  ☐    No  ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  ☒    No  ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).    Yes  ☒    No  ☐

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§ 229.405 of this chapter) is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  ☒

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 13(a) of the Exchange Act.  ☒

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    ☐  Yes    ☒  No

The aggregate market value of the voting common stock held by non-affiliates of the registrant as of June 30, 2017, the last business day of the most recently completed second fiscal quarter, was approximately $248 million.

Number of shares of the registrant’s common stock outstanding at March 2, 2018: 301,770,671 shares.

Documents incorporated by reference: Portions of the registrant’s proxy statement for its 2018 annual meeting of stockholders to be filed pursuant to Regulation 14A within 120 days after the registrant’s fiscal year end are incorporated by reference into Part III of this Annual Report on Form 10-K.

EXPLANATORY NOTE

This Amendment No. 1 on Form 10-K/A (this “Amendment No. 1”) to the Annual Report on Form 10-K of Eclipse Resources Corporation (the “Company”) for the fiscal year ended December 31, 2017, originally filed with the U.S. Securities and Exchange Commission (the “SEC”) on March 2, 2018 (the “Original Filing”), is being filed solely to correct an inconsistent statement in the reserve report (the “Reserve Report”) of Netherland, Sewell & Associates, Inc., the Company’s independent petroleum engineers (“NSAI”), filed by the Company as Exhibit 99.1 to the Original Filing, regarding the extent to which the Reserve Report takes into account future contractual arrangements for firm transportation costs. The Company is filing the corrected Exhibit 99.1 with this Amendment No. 1, together with the consent of NSAI included as Exhibit 23.2 with this Amendment No. 1. Specifically, the statement “Additionally, we have made no investigation of any firm transportation contracts that may be in place for these properties; no adjustments have been made to our estimates of future revenue to account for such contracts.” on page 2 of such Reserve Report was changed to read “Additionally, we have made no specific investigation of any current or future firm transportation contracts that may be in place for these properties. Our estimates of future net revenue include fees and pricing effects related to these contracts to the extent that such costs and prices are accounted for in the field- and lease-level accounting statements.” There were no other changes to the Reserve Report.

Pursuant to Rule 12b-15 under the Securities Exchange Act of 1934, as amended, this Amendment No. 1 also contains new certifications pursuant to Section 302 of the Sarbanes-Oxley Act of 2002, which are attached hereto. Because no financial statements have been included in this Amendment No. 1 and this Amendment No. 1 does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4, and 5 of the certifications have been omitted.

Except as described above, no other changes have been made to the Original Filing, and this Amendment No. 1 does not modify, amend or update in any way any of the financial or other information contained in the Original Filing. This Amendment No. 1 does not reflect events that may have occurred subsequent to the filing date of the Original Filing. This Amendment No. 1 should be read in conjunction with the Original Filing and the Company’s other filings with the SEC subsequent to the filing of the Original Filing.

The consolidated financial statements are listed on the Index to Financial Statements beginning on page F-1 of the Original Filing. The consolidated financial statements were previously filed with the Original Filing.

No financial statement schedules are submitted because of the absence of the conditions under which they are required, the required information is insignificant or because the required information is included in the consolidated financial statements.

EXHIBIT INDEX

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.