UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report: March 29, 2016

(Date of earliest event reported)

(Exact name of registrant as specified in its charter)

1400 Woodloch Forest Drive, Suite 300

The Woodlands, Texas 77380

(Address of principal executive offices) (Zip Code)

(281) 298-4246

(Registrant’s telephone number, including area code)

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Item 1.01 Entry into a Material Definitive Agreement.

On March 29, 2016, Earthstone Energy, Inc. (“Earthstone”), Lynden Energy Corp., a corporation existing under the laws of British Columbia (“Lynden”), and 1058286 B.C. Ltd., a company organized under the laws of British Columbia, Canada and wholly-owned subsidiary of Earthstone (“Merger Sub”), entered into an amendment (the “Amendment”) to the Arrangement Agreement dated December 16, 2015 (the “Arrangement Agreement”), among Earthstone, Merger Sub and Lynden.

The Amendment clarifies certain technical matters related to the mechanics of the Arrangement, mainly that Merger Sub will be the entity that (i) acquires all of the outstanding common stock of Lynden and (ii) amalgamates with Lynden to form one corporate entity with Lynden surviving the amalgamation as a wholly-owned subsidiary of Earthstone. The Amendment also extends the date by which Lynden must hold its special meeting to May 27, 2016. Finally, the Amendment makes miscellaneous, conforming changes that are consistent with the foregoing summary.  

The foregoing summary of the Amendment does not purport to be complete and is subject to, and qualified in its entirety by, the full text of the Amendment, which is attached to this report as Exhibit 2.1 and incorporated herein by reference.

Forward-Looking Statements

This report contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Statements that are not strictly historical statements constitute forward-looking statements and may often, but not always, be identified by the use of such words such as “expects,” “believes,” “intends,” “anticipates,” “plans,” “estimates,” “potential,” “possible,” or “probable” or statements that certain actions, events or results “may,” “will,” “should,” or “could” be taken, occur or be achieved. The forward-looking statements include statements about the expected benefits of the proposed transaction to Earthstone and Lynden and their stockholders, the anticipated completion of the proposed transaction or the timing thereof, the expected future reserves, production, financial position, business strategy, revenues, earnings, costs, capital expenditures and debt levels of the combined company, and plans and objectives of management for future operations. Forward-looking statements are based on current expectations and assumptions and analyses made by Earthstone, Lynden and their management in light of experience and perception of historical trends, current conditions and expected future developments, as well as other factors appropriate under the circumstances. However, whether actual results and developments will conform to expectations is subject to a number of material risks and uncertainties, including but not limited to: the ability to obtain stockholder, court and regulatory approvals of the proposed transaction; the ability to complete the proposed transaction on anticipated terms and timetable; Earthstone’s and Lynden’s ability to integrate successfully after the transaction and achieve anticipated benefits from it; the possibility that various closing conditions for the transaction may not be satisfied or waived; risks relating to any unforeseen liabilities of Earthstone or Lynden; declines in oil, natural gas liquids or natural gas prices; the level of success in exploration, development and production activities; adverse weather conditions that may negatively impact development or production activities; the timing of exploration and development expenditures; inaccuracies of reserve estimates or assumptions underlying them; revisions to reserve estimates as a result of changes in commodity prices; impacts to financial statements as a result of impairment write-downs; risks related to level of indebtedness and periodic redeterminations of the borrowing base under Earthstone’s credit agreement; Earthstone’s ability to generate sufficient cash flows from operations to meet the internally funded portion of its capital expenditures budget; Earthstone’s ability to obtain external capital to finance exploration and development operations and acquisitions; the ability to successfully complete potential asset dispositions and the risks related thereto; the impacts of hedging on results of operations; uninsured or underinsured losses resulting from oil and natural gas operations; Earthstone’s ability to replace oil and natural gas reserves; any loss of senior management or technical personnel; and risks arising out of hedging transactions. Earthstone’s annual report on Form 10-K for the year ended December 31, 2015, recent current reports on Form 8-K, and other Securities and Exchange Commission (“SEC”) filings discuss some of the important risk factors identified that may affect Earthstone’s business, results of operations, and financial condition. Lynden’s annual report on Form 10-K for the year ended June 30, 2015, quarterly reports on Form 10-Q, recent current reports on Form 8-K, and other SEC filings discuss some of the important risk factors identified that may affect Lynden’s business, results of operations, and financial condition. Earthstone and Lynden undertake no obligation to revise or update publicly any forward-looking statements except as required by law.

Additional Information

This report does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of a vote or proxy. In connection with the proposed transaction, Earthstone and Lynden will file with the SEC a joint proxy and information statement/circular and other relevant documents to be mailed by Lynden and Earthstone to their respective security holders in connection with the proposed transaction. The joint proxy and information statement/circular will also be filed with the Canadian securities regulators. WE URGE INVESTORS AND SECURITY HOLDERS TO READ THE JOINT PROXY AND INFORMATION STATEMENT/CIRCULAR AND ANY OTHER RELEVANT DOCUMENTS WHEN THEY BECOME AVAILABLE, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT EARTHSTONE, LYNDEN AND THE PROPOSED TRANSACTION. Investors and security holders will be able to obtain these materials (when they are available)

and other documents filed with the SEC and the Canadian securities regulators free of charge at the SEC’s website, www.sec.gov and at the System for Electronic Document Analysis and Retrieval (“SEDAR”) at www.sedar.com. In addition, a copy of the definitive joint proxy and information statement/circular (when it becomes available) may be obtained free of charge from Earthstone’s website at www.earthstoneenergy.com, or from Lynden’s website at www.lyndenenergy.com. Investors and security holders may also read and copy any reports, statements and other information filed by Lynden or Earthstone, with the SEC, at the SEC public reference room at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 or visit the SEC’s website for further information on its public reference room. In addition, the documents filed with the SEC by Earthstone can be obtained free of charge from Earthstone’s website at www.earthstoneenergy.com or by contacting Earthstone by mail at 1400 Woodloch Forest Drive, Suite 300, The Woodlands, Texas, 77380, or by telephone at (281) 298-4246. The documents filed with the SEC by Lynden can be obtained free of charge from Lynden’s website at www.lyndenenergy.com or by contacting Lynden by mail at 595 Burrard Street, Suite 2900, Vancouver, British Columbia, V7X 1J5 or by telephone at (604) 629-2991.

Participants in the Solicitation

Earthstone, Lynden and their respective directors, executive officers and certain other members of management and employees may be deemed to be participants in the solicitation of proxies in respect of the proposed transaction. Information regarding Earthstone’s directors and executive officers is available in its proxy statement filed with the SEC by Earthstone on September 21, 2015 in connection with its 2015 annual meeting of stockholders, and information regarding Lynden’s directors and executive officers is available in its management proxy circular filed by Lynden with the SEC on October 21, 2015 in connection with its 2015 annual meeting of stockholders. Other information regarding the participants in the proxy solicitation and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in the joint information statement/circular and other relevant materials to be filed with the SEC and the Canadian securities regulators when they become available.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

The following exhibit is filed with this Current Report on Form 8-K:

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

EXHIBIT INDEX