# EDGAR Filing Document

**Accession Number:** 0001273441
**File Stem:** 0001013594-25-001192
**Filing Date:** 2025-10
**Character Count:** 21895
**Document Hash:** 6137f7d87bb84896a60a193b32cf8999
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001013594-25-001192.hdr.sgml**: 20251006

**ACCESSION NUMBER**: 0001013594-25-001192

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20251006

**DATE AS OF CHANGE**: 20251006

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** GRAN TIERRA ENERGY INC.
- **CENTRAL INDEX KEY:** 0001273441
- **STANDARD INDUSTRIAL CLASSIFICATION:** CRUDE PETROLEUM & NATURAL GAS [1311]
- **ORGANIZATION NAME:** 01 Energy & Transportation
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-83601
- **FILM NUMBER:** 251378024

**BUSINESS ADDRESS:**
- **STREET 1:** 500 CENTRE STREET SE
- **CITY:** CALGARY
- **STATE:** A0
- **ZIP:** T2G 1A6
- **BUSINESS PHONE:** (403) 265-3221

**MAIL ADDRESS:**
- **STREET 1:** 500 CENTRE STREET SE
- **CITY:** CALGARY
- **STATE:** A0
- **ZIP:** T2G 1A6

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** GRAN TIERRA ENERGY, INC.
- **DATE OF NAME CHANGE:** 20051130

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** GOLDSTRIKE INC
- **DATE OF NAME CHANGE:** 20040113

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** GOLKSTRIKE INC
- **DATE OF NAME CHANGE:** 20031216
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Equinox Partners Investment Management LLC
- **CENTRAL INDEX KEY:** 0000938552

**ORGANIZATION NAME:**
- **EIN:** 133360821
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D

**BUSINESS ADDRESS:**
- **STREET 1:** THREE STAMFORD PLAZA
- **STREET 2:** 301 TRESSER BLVD, 13TH FL
- **CITY:** STAMFORD
- **STATE:** CT
- **ZIP:** 06901
- **BUSINESS PHONE:** 203-516-2270

**MAIL ADDRESS:**
- **STREET 1:** THREE STAMFORD PLAZA
- **STREET 2:** 301 TRESSER BLVD, 13TH FL
- **CITY:** STAMFORD
- **STATE:** CT
- **ZIP:** 06901

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Equinox Partners Investment Management
- **DATE OF NAME CHANGE:** 20201005

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MASON HILL ADVISORS LLC
- **DATE OF NAME CHANGE:** 20120913

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MASON HILL ASSET MANAGEMENT INCET AL
- **DATE OF NAME CHANGE:** 19950221

## Ex-99

EXHIBIT 99.1

#### JOINT FILING AGREEMENT

The undersigned hereby agree that the statement on Schedule 13D with respect to the Common Stock, par value $0.001 per share, of Gran Tierra Energy Inc. dated as of the date hereof is, and any further amendments thereto signed by each of the undersigned shall be, filed on behalf of each of the undersigned pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended.

Dated: October 6, 2025

---

| | |
|:---|:---|
| EQUINOX PARTNERS INVESTMENT MANAGEMENT LLC | EQUINOX PARTNERS INVESTMENT MANAGEMENT LLC |
| /s/ Sean M. Fieler | /s/ Sean M. Fieler |
| Name: | Sean M. Fieler |
| Title: | Manager |
| EQUINOX PARTNERS, L.P. | EQUINOX PARTNERS, L.P. |
| /s/ Sean M. Fieler | /s/ Sean M. Fieler |
| Name: | Sean M. Fieler |
| Title: | Manager of Equinox Partners Investment Management LLC, the Investment Manager of Equinox Partners, L.P. |
| KUROTO FUND LP | KUROTO FUND LP |
| /s/ Sean M. Fieler | /s/ Sean M. Fieler |
| Name: | Sean M. Fieler |
| Title: | Manager of Equinox Partners Investment Management LLC, the Investment Manager of Kuroto Fund LP |
| MASON HILL PARTNERS, LP | MASON HILL PARTNERS, LP |
| /s/ Sean M. Fieler | /s/ Sean M. Fieler |
| Name: | Sean M. Fieler |
| Title: | Manager of Equinox Partners Investment Management LLC, the Investment Manager of Mason Hill Partners, LP |
| /s/ Sean M. Fieler | /s/ Sean M. Fieler |
| SEAN M. FIELER | SEAN M. FIELER |

---

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**GRAN TIERRA ENERGY INC.**

*(Name of Issuer)*

**Common Stock, par value $0.001 per share**

*(Title of Class of Securities)*

**38500T200**

*(CUSIP Number)*

**Eric Wagner**<br>500 Fifth Avenue<br>New York NY 10110<br>(212) 880-9845

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**09/30/2025**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **38500T200** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Equinox Partners Investment Management LLC** | Name of reporting person<br>**Equinox Partners Investment Management LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**5097688.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**5097688.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**5097688.00** | Aggregate amount beneficially owned by each reporting person<br>**5097688.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**14.4%** | Percent of class represented by amount in Row (11)<br>**14.4%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IA** | Type of Reporting Person (See Instructions)<br>**IA** | |

---

**Comment for Reporting Person:** Includes 2,051,427 shares of Common Stock, par value $0.001 per share (the "Shares") of Gran Tierra Energy Inc. (the "Issuer") held in one or more client accounts over which Equinox Partners Investment Management LLC, as investment advisor, has shared voting and dispositive power. The filing of this statement should not be deemed as admission that Equinox Partners Investment Management LLC is, for the purposes of Section 13 of the Act, the beneficial owner of the Shares held in such client account(s).

| **CUSIP No.** | **38500T200** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Equinox Partners, L.P.** | Name of reporting person<br>**Equinox Partners, L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**2163682.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**2163682.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**2163682.00** | Aggregate amount beneficially owned by each reporting person<br>**2163682.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**6.1%** | Percent of class represented by amount in Row (11)<br>**6.1%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **38500T200** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Kuroto Fund LP** | Name of reporting person<br>**Kuroto Fund LP** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**538700.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**538700.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**538700.00** | Aggregate amount beneficially owned by each reporting person<br>**538700.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**1.5%** | Percent of class represented by amount in Row (11)<br>**1.5%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **38500T200** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Mason Hill Partners, LP** | Name of reporting person<br>**Mason Hill Partners, LP** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**343879.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**343879.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**343879.00** | Aggregate amount beneficially owned by each reporting person<br>**343879.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**1%** | Percent of class represented by amount in Row (11)<br>**1%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **38500T200** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Sean M. Fieler** | Name of reporting person<br>**Sean M. Fieler** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**X1** | Citizenship or place of organization<br>**X1** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**5097688.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**5097688.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**5097688.00** | Aggregate amount beneficially owned by each reporting person<br>**5097688.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**14.4%** | Percent of class represented by amount in Row (11)<br>**14.4%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Comment for Reporting Person:** See Footnote 1 on page 2. The filing of this statement should not be deemed an admission that Mr. Fieler is, for the purposes of Section 13 of the Act, the beneficial owner of the Shares held in such client account(s).

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock, par value $0.001 per share

**(b) Name of Issuer:**
GRAN TIERRA ENERGY INC.

**(c) Address of Issuer's Principal Executive Offices:**
500 CENTRE STREET SE, CALGARY, Z4, T2G 1A6

This Statement on Schedule 13D (this "Schedule 13D") relates to the Common Stock, par value $0.001 per share (the "Shares") of Gran Tierra Energy Inc., a Delaware corporation (the "Issuer"), whose principal executive offices are located at 500 Centre Street S.E., Calgary, Alberta T2G 1A6, Canada.

**Item 4. Purpose of Transaction**

The Reporting Persons purchased the Shares based on the Reporting Persons' belief that the Shares, when purchased, were undervalued and represented an attractive investment opportunity. Depending upon overall market conditions, other investment opportunities available to the Reporting Persons, and the availability of Shares at prices that would make the purchase or sale of Shares desirable, the Reporting Persons may endeavor to increase or decrease their position in the Issuer through, among other things, the purchase or sale of Shares on the open market or in private transactions or otherwise, on such terms and at such times as the Reporting Persons may deem advisable.
Brad Virbitsky, a portfolio manager and partner at EPIM, was appointed to the Issuer's Board of Directors as an independent director, effective September 30, 2025, prompting the change from a 13G to a 13D filer.
No Reporting Person has any present plan or proposal which would relate to or result in any of the matters set forth in Item 4(a) through (j) of this Schedule 13D except as set forth herein or such as would occur upon or in connection with completion of, or following, any of the actions discussed herein. The Reporting Persons intend to review their investment in the Issuer on a continuing basis. Depending on various factors including, without limitation, the Issuer's financial position and investment strategy, the price levels of the Shares, conditions in the securities markets and general economic and industry conditions, the Reporting Persons may in the future take such actions with respect to their investment in the Issuer as they deem appropriate including, without limitation, engaging in communications with management and the Board of Directors, engaging in discussions with stockholders of the Issuer or third parties, including potential acquirers and service providers, about the Issuer and the Reporting Persons' investment, making proposals to the Issuer concerning changes to the capital allocation strategy, capitalization, ownership structure, including a sale of the Issuer as a whole or in parts, Board of Directors structure (including Board of Directors composition) or operations of the Issuer, purchasing additional Shares, selling some or all of their Shares, engaging in short selling of or any hedging or similar transaction with respect to the Shares, or changing their intention with respect to any and all matters referred to in Item 4.

**Item 5. Interest in Securities of the Issuer**

**(a)**
The aggregate percentage of Shares reported owned by the Reporting Persons is based upon 35,290,955 Shares outstanding, which is the total number of Shares outstanding as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on July 31, 2025.
As of the date hereof, the Reporting Persons beneficially own an aggregate of 5,097,688 Shares, constituting approximately 14.4% of the outstanding Shares. See rows (11) and (13) of the cover pages to this Schedule 13D for the aggregate number of Shares and percentage of the outstanding Shares beneficially owned by each of the Reporting Persons. See rows (7) through (10) of the cover pages to this Schedule 13D, including the notes relating thereto, for the number of Shares as to which each Reporting Person has the sole or shared power to vote or direct the vote and the sole or shared power to dispose or to direct the disposition.
The filing of this Schedule 13D shall not be deemed an admission that the Reporting Persons are, for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, the beneficial owners of any securities of the Issuer that he or it does not directly own. Each of the Reporting Persons specifically disclaims beneficial ownership of the securities reported herein that he or it does not directly own.
The Reporting Persons expect that Mr. Virbitsky will be awarded certain securities of the Issuer as compensation for his serving as a member of the Issuer's Board of Directors.

**(b)**
See item 5(a) above.

**(c)**
The Reporting Persons have not entered into any transactions in Shares during the past sixty days.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

Except as described above, the only agreement that the Reporting Persons have entered into is a joint filing agreement, dated as October 6, 2025, a copy of which is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Equinox Partners Investment Management LLC

**Signature:** /s/ Sean M. Fieler

**Name/Title:** Sean M. Fieler, Manager

**Date:** 10/06/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Equinox Partners, L.P.

**Signature:** /s/ Sean M. Fieler

**Name/Title:** Sean M. Fieler, Manager of Equinox Partners Investment Management LLC, the Investment Manager of Equinox Partners, L.P.

**Date:** 10/06/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Kuroto Fund LP

**Signature:** /s/ Sean M. Fieler

**Name/Title:** Sean M. Fieler, Manager of Equinox Partners Investment Management LLC, the Investment Manager of Kuroto Fund LP

**Date:** 10/06/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Mason Hill Partners, LP

**Signature:** /s/ Sean M. Fieler

**Name/Title:** Sean M. Fieler, Manager of Equinox Partners Investment Management LLC, the Investment Manager of Mason Hill Partners, LP

**Date:** 10/06/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Sean M. Fieler

**Signature:** /s/ Sean M. Fieler

**Name/Title:** Sean M. Fieler

**Date:** 10/06/2025