Filing of Definitive Proxy Statement for Special Meeting of Stockholders to Consider Approval of Sale of Colombian and Ecuadorian Businesses

CALGARY, Alberta, Sept. 23, 2026 (GLOBE NEWSWIRE) -- Gran Tierra Energy Inc. ("Gran Tierra" or the "Company") (NYSE American:GTE) (TSX:GTE) (LSE:GTE) announces that it filed its definitive proxy statement (the "Proxy Statement") with the U.S. Securities and Exchange Commission (the "SEC") on September 15, 2026 in connection with the Company's special meeting of stockholders (the "Special Meeting"). At the Special Meeting, stockholders will be asked to approve the previously announced sale of Gran Tierra's Colombian and Ecuadorian businesses to Maurel & Prom for total consideration of approximately $1.33 billion, subject to adjustment (the "Sale"), pursuant to the terms and conditions of the Share Sale and Purchase Agreement entered into on August 5, 2026 (the "Share Purchase Agreement"). Stockholders will also vote on an advisory proposal concerning certain transaction-related executive compensation and a proposal to adjourn the Special Meeting, if necessary, to solicit additional proxies.

Gran Tierra’s Board of Directors unanimously recommends that its stockholders approve the Share Purchase Agreement and the transactions contemplated thereby, including the Sale (the “Sale Proposal”). The approval of the Sale Proposal requires the affirmative vote of the holders of a majority of the outstanding shares of common stock entitled to vote thereon at the Special Meeting, voting in person or represented by proxy.

The Sale continues to progress toward completion. On September 22, 2026, Gran Tierra announced the successful completion of the solicitation of consents from holders of its 9.750% Senior Secured Amortizing Notes due 2031 to effect certain proposed amendments to the indenture under which the notes were issued, satisfying a key condition to closing and enabling a subsidiary of Maurel & Prom to assume the notes at completion of the Sale. With noteholder approval now in hand, stockholder approval at the Special Meeting is among the final steps remaining, alongside the regulatory approvals in Colombia and Ecuador.

Proxy materials are expected to be delivered to stockholders by September 24, 2026. Stockholders who have not received their proxy materials, have questions or require assistance voting their shares should contact their broker, bank or other intermediary, as applicable, or Kingsdale Advisors, the Company’s strategic stockholder advisor and proxy solicitation agent, toll-free in North America at (855) 476-7987, by call or text at (437) 561-5013, or by email at contactus@kingsdaleadvisors.com.

The Special Meeting will be held virtually on October 9, 2026 at 10:00 a.m. Mountain Time (12:00 p.m. Eastern Time). The Special Meeting will be held in a virtual-only format by live webcast at https://meetings.lumiconnect.com/400-691-155-645; no physical or in-person meeting will be held. Holders of shares as of the close of business on September 14, 2026, the record date for the Special Meeting, will be able to attend the Special Meeting online, vote their shares electronically and submit questions during the meeting and at any adjournment or postponement thereof.

Stockholders are encouraged to read the Proxy Statement, the Share Purchase Agreement attached as Annex A thereto and the other annexes carefully and in their entirety and submit their proxy or voting instructions as promptly as possible and, in any event, no later than 10:00 a.m. Mountain Time on October 8, 2026, by following the instructions included with their proxy materials. Stockholders who hold their shares in “street name” should follow the instructions received from their broker, bank, or other intermediary to vote their shares.

The Proxy Statement and other documents filed by the Company with the SEC are available free of charge at www.sec.gov. The Proxy Statement and additional information concerning the Special Meeting are also available at https://www.grantierra.com/events/special-meeting-of-shareholders/.

About Gran Tierra Energy Inc.

Gran Tierra Energy Inc., together with its subsidiaries, is an independent international energy company currently focused on oil and natural gas exploration and production in Canada, Colombia and Ecuador. The Company has entered into an exploration, development and production sharing agreement in Azerbaijan, which remains subject to ratification. Upon completion of the Sale, the Company's producing operations will be focused on Canada, and the Company will continue to pursue its interests in Azerbaijan and additional new growth opportunities that would further strengthen the Company’s portfolio. The Company’s common stock trades on the NYSE American, the Toronto Stock Exchange and the London Stock Exchange under the ticker symbol GTE. Additional information concerning Gran Tierra is available at www.grantierra.com. Except to the extent expressly stated otherwise, information on the Company’s website or accessible from our website or any other website is not incorporated by reference into and should not be considered part of this press release. Investor inquiries may be directed to info@grantierra.com or (403) 265-3221.

Solicitation of Proxies

The Company and its directors and executive officers may be deemed to be participants in the solicitation of proxies in respect of the Special Meeting. Information regarding the Company’s directors and executive officers is contained in the Proxy Statement.