Gran Tierra Energy Inc.

Item 5.07. Submission of Matters to a Vote of Security Holders. On October 9, 2026, Gran Tierra Energy Inc., a Delaware corporation (the “Company”), held a special meeting of stockholders (the “Special Meeting”) to consider and act upon the following matters: (1) to approve the Share Sale and Purchase Agreement (the “Share Purchase Agreement”) among the Company, Gran Tierra Energy International Holdings GmbH, a company organized and existing under the laws of Switzerland, Maurel & Prom Andina S.A.S., a company organized and existing under the laws of France, and Établissements Maurel et Prom S.A., a company organized and existing under the laws of France, and the transactions contemplated thereby (the “Sale”), as such Sale may be considered to constitute the sale of substantially all of the Company’s property and assets within the meaning of Section 271 of the General Corporation Law of the State of Delaware (the “Sale Proposal”), (2) to approve, on an advisory (non-binding) basis, the compensation that may, under certain circumstances, be paid or provided by the Company to its named executive officers in connection with the Share Purchase Agreement and the Sale (the “Compensation Proposal”), and (3) to adjourn the Special Meeting, if necessary or appropriate, in order to solicit additional proxies if there are insufficient votes at the time of the Special Meeting to approve the Sale Proposal (the “Adjournment Proposal”). The proposals are described in more detail in the Company’s definitive proxy statement filed with the Securities and Exchange Commission on September 15, 2026 (the “Proxy Statement”), which is available on the U.S. Securities and Exchange Commission’s website at www.sec.gov. As of September 14, 2026, the record date for the Special Meeting, 35,380,429 shares of the common stock, par value $0.01 per share, of the Company (the “Common Stock”) were issued and outstanding and entitled to vote at the Special Meeting. A total of 19,390,935 shares, or approximately 54.81% of the issued and outstanding shares of Common Stock entitled to vote, were present or represented by proxy at the Special Meeting, constituting a quorum. The results of the stockholders’ votes are reported below: Shares Voted For Shares Voted Against Shares Abstaining Broker Non-Votes ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Sale Proposal 19,351,115 32,492 7,328 — Compensation Proposal 9,557,007 9,658,068 175,860 — Adjournment Proposal 19,304,196 62,742 23,997 — Because there were sufficient votes at the time of the Special Meeting to approve the Sale Proposal, a vote on the Adjournment Proposal was not necessary. Consummation of the transactions contemplated by the Share Purchase Agreement is subject to the satisfaction of certain closing conditions, all as set forth in the Share Purchase Agreement and discussed in detail in the Proxy Statement. Assuming satisfaction or waiver of such closing conditions, the Company expects the closing of the Sale to occur by December 31, 2026.

Item 8.01. Other Events. Also on October 9, 2026, the Company issued a press release announcing that the Company’s stockholders had approved the Share Purchase Agreement and the transactions contemplated thereby, including the Sale, at the Special Meeting. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.