Equinox group reports 11.7% stake in Gran Tierra

Gran Tierra Energy Inc. shareholder group led by Equinox Partners Investment Management LLC filed Amendment No. 4 to Schedule 13D regarding its holdings of Gran Tierra common stock.

Rhea-AI Filing Summary

Gran Tierra Energy Inc. shareholder group led by Equinox Partners Investment Management LLC filed Amendment No. 4 to Schedule 13D regarding its holdings of Gran Tierra common stock. The reporting persons collectively beneficially own 4,149,531 Shares, representing 11.7% of the outstanding common stock, based on 35,380,429 Shares outstanding as reported in Gran Tierra’s Form 10-Q filed August 5, 2026.

Equinox Partners Investment Management LLC is investment adviser to client accounts that hold a portion of these Shares, and the filing states that all Shares were acquired using approximately $22,163,850.39 of client investment capital, including commissions. Shares may be held in margin accounts and pledged as collateral for debit balances. The reporting persons and Sean M. Fieler expressly disclaim beneficial ownership of Shares they do not directly own, including 43,917 Shares underlying deferred stock units awarded to former director Brad Virbitsky. The filing notes that, other than transactions listed on Schedule 1 or previously reported, there have been no other transactions in the past 60 days.

Key Figures

Beneficial ownership: 4,149,531 Shares Ownership percentage: 11.7% Shares outstanding: 35,380,429 Shares +5 more

8 metrics

Beneficial ownership 4,149,531 Shares Aggregate Gran Tierra common shares beneficially owned by reporting persons

Ownership percentage 11.7% Percentage of outstanding Gran Tierra Shares represented by 4,149,531 Shares

Shares outstanding 35,380,429 Shares Gran Tierra Shares outstanding per Form 10-Q filed August 5, 2026

Total purchase funds $22,163,850.39 Aggregate funds, including commissions, used to purchase Shares held by reporting persons

Equinox Partners, L.P. holdings 1,680,415 Shares Shares with shared voting and dispositive power by Equinox Partners, L.P.

Kuroto Fund holdings 429,147 Shares Shares with shared voting and dispositive power by Kuroto Fund

Mason Hill Partners holdings 357,833 Shares Shares with shared voting and dispositive power by Mason Hill Partners

Director deferred stock units 43,917 Shares Shares underlying deferred stock units awarded to Brad Virbitsky

Key Terms

Schedule 13D, beneficially own, margin accounts, dispositive power, +2 more

6 terms

Schedule 13D regulatory

"constitutes Amendment No. 4 to the (as previously amended, the "") filed"

A Schedule 13D is a legal document that investors file with regulators when they buy a large enough stake in a company to potentially influence its management or decisions. It provides details about the investor’s intention, ownership stake, and plans, helping other investors understand who is gaining control and what their motives might be.

beneficially own financial

"Reporting Persons beneficially own an aggregate of 4,149,531 Shares, constituting approximately"

Beneficially own means having the economic rights and risks of a security—such as the right to receive dividends, sell the shares, or profit from price changes—whether or not your name appears on the official share register. Think of it like renting a car: you use it and reap the benefits even if the title lists someone else. Investors care because beneficial ownership determines who truly controls value, must be disclosed under securities rules, and can signal potential influence or trading activity that affects a stock’s price.

margin accounts financial

"Reporting Persons may effect purchases of Shares through margin accounts maintained"

A margin account is a brokerage account that lets an investor borrow money from the broker to buy more securities than they could with cash alone, using the securities in the account as security for the loan. Think of it like a mortgage for stock purchases: borrowing increases potential gains but also magnifies losses, can trigger a forced sale if the account falls below required limits, and carries interest costs—factors investors must manage carefully.

dispositive power financial

"sole or shared power to dispose or to direct the disposition"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

deferred stock units financial

"was awarded deferred stock units by the Issuer that are convertible into 43,917 Shares"

Deferred stock units are promises from a company to give an employee shares of stock at a future date, often after certain conditions are met or after leaving the company. They function like a form of delayed compensation, allowing employees to earn shares over time. For investors, they represent potential future ownership in the company, but do not provide immediate voting rights or dividends until the shares are actually received.

beneficial owner regulatory

"not be deemed as admission that Equinox Partners Investment Management LLC is, for the purposes"

A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What percentage of Gran Tierra Energy (GTE) does the Equinox group report owning?

The reporting persons state they beneficially own 4,149,531 Shares of Gran Tierra Energy, representing approximately 11.7% of the company’s outstanding common stock, based on 35,380,429 Shares outstanding reported in Gran Tierra’s Form 10-Q filed August 5, 2026.

How many Gran Tierra Energy (GTE) shares does Equinox Partners Investment Management LLC report?

Equinox Partners Investment Management LLC reports shared voting and dispositive power over 4,149,531 Shares. This includes 1,682,136 Shares held in one or more client accounts over which it has shared voting and dispositive power as investment adviser.

What total investment was used to acquire the reported GTE shares?

The reporting persons state that the shares were purchased using client investment capital totaling approximately $22,163,850.39, including commissions. These purchases may involve margin accounts maintained with prime brokers, where shares can be pledged as collateral for debit balances.

How many outstanding Gran Tierra Energy (GTE) shares are used to calculate the 11.7% stake?

The 11.7% beneficial ownership is calculated using 35,380,429 Shares outstanding, which the reporting persons reference from Gran Tierra Energy’s Quarterly Report on Form 10-Q filed with the SEC on August 5, 2026.

Do the reporting persons claim beneficial ownership of director Brad Virbitsky’s deferred stock units in GTE?

No. The filing explains that Brad Virbitsky was awarded deferred stock units convertible into 43,917 Shares as director compensation, and the reporting persons expressly disclaim beneficial ownership of any Shares held by Mr. Virbitsky.

Which entities are included in the Equinox reporting group for Gran Tierra Energy (GTE)?

The group includes Equinox Partners Investment Management LLC, Equinox Partners, L.P., Kuroto Fund, Mason Hill Partners, and Sean M. Fieler, each reporting shared voting and dispositive power over specified blocks of Gran Tierra common stock.

Have there been recent transactions in GTE shares by the reporting persons?

The reporting persons state that during the past 60 days they have not entered into any Gran Tierra share transactions except those listed on Schedule 1 to the statement or previously reported in earlier filings.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 08/13/2026 - 06:26 PM EDT Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 4)

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
Kleinberg, Kaplan, Wolff & Cohen P.C., 500 Fifth Avenue
New York, NY, 10110
(212) 880-9845

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

08/11/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

schemaVersion:

SCHEDULE 13D

CUSIP Number(s): 38500T200

1

Name of reporting person

Equinox Partners Investment Management LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 4,149,531.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 4,149,531.00

11

Aggregate amount beneficially owned by each reporting person

4,149,531.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

11.7 %

14

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person:

Note to Row 8: Includes 1,682,136 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).

SCHEDULE 13D

CUSIP Number(s): 38500T200

1

Name of reporting person

Equinox Partners, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 1,680,415.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 1,680,415.00

11

Aggregate amount beneficially owned by each reporting person

1,680,415.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

4.8 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP Number(s): 38500T200

1

Name of reporting person

Kuroto Fund LP

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 429,147.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 429,147.00

11

Aggregate amount beneficially owned by each reporting person

429,147.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.2 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP Number(s): 38500T200

1

Name of reporting person

Mason Hill Partners, LP

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 357,833.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 357,833.00

11

Aggregate amount beneficially owned by each reporting person

357,833.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.0 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP Number(s): 38500T200

1

Name of reporting person

Sean M. Fieler

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 4,149,531.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 4,149,531.00

11

Aggregate amount beneficially owned by each reporting person

4,149,531.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

11.7 %

14

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person:

Note to Row 8: 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).

SCHEDULE 13D

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 S.E., Calgary, ALBERTA, CANADA , T2G 1A6.
Item 1 Comment: The following constitutes Amendment No. 4 (this "Amendment No. 4") to the Schedule 13D (as previously amended, the "Schedule 13D") filed by the undersigned with respect to shares of the Common Stock, par value $0.001 per share (the "Shares") of Gran Tierra Energy Inc. (the "Issuer"). This Amendment No. 4 amends the Schedule 13D as specifically set forth herein.
Item 3.	Source and Amount of Funds or Other Consideration
	Item 3 of the Schedule 13D is hereby amended and restated in its entirety as follows: All of the Shares to which this Schedule 13D relates were purchased using the investment capital of the applicable clients of EPIM. The aggregate amount of funds used for the purchase of the Shares held by the Reporting Persons is approximately $22,163,850.39, including commissions. The Reporting Persons may effect purchases of Shares through margin accounts maintained for EPIM's clients with prime brokers, which extend margin credit as and when required to open or carry positions in their margin accounts, subject to applicable federal margin regulations, stock exchange rules and such firms' credit policies. Shares may be held in margin accounts and may be pledged as collateral security for the repayment of debit balances in such accounts. Since other securities may be held in such margin accounts, it may not be possible to determine the amounts, if any, of margin used to purchase the Shares.
Item 5.	Interest in Securities of the Issuer
(a)	(a) - (b) The aggregate percentage of Shares reported owned by the Reporting Persons is based upon 35,380,429 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 August 5, 2026. As of the date hereof, the Reporting Persons beneficially own an aggregate of 4,149,531 Shares, constituting approximately 11.7% 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. Brad Virbitsky, an EPIM employee, was appointed to the Issuer's Board of Directors as an independent director effective September 30, 2025, and resigned from the Issuer's Board of Directors on March 12, 2026. Mr. Virbitsky was awarded deferred stock units by the Issuer that are convertible into 43,917 Shares as compensation for his serving as a member of the Issuer's Board of Directors. The Reporting Persons disclaim beneficial ownership of any Shares held by Mr. Virbitsky.
(b)	See Item 5(a).
(c)	During the past sixty (60) days, the Reporting Persons have not entered into any transactions in the Shares except as set forth on Schedule 1 hereto or as previously reported on Schedule 13D.
(d)	No Person is known to the Reporting Persons to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, any Shares that may be beneficially owned by the Reporting Persons.
(e)	Not applicable.
Item 7.	Material to be Filed as Exhibits.
	Exhibit 99 - Schedule 1

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.

Equinox Partners Investment Management LLC

Signature:	/s/ Sean M. Fieler
Name/Title:	Manager
Date:	08/13/2026

Equinox Partners, L.P.

Signature:	/s/ Sean M. Fieler
Name/Title:	Manager of Equinox Partners Investment Management LLC, the Investment Manager of Equinox Partners, L.P.
Date:	08/13/2026

Kuroto Fund LP

Signature:	/s/ Sean M. Fieler
Name/Title:	Manager of Equinox Partners Investment Management LLC, the Investment Manager of Kuroto Fund LP
Date:	08/13/2026

Mason Hill Partners, LP

Signature:	/s/ Sean M. Fieler
Name/Title:	Manager of Equinox Partners Investment Management LLC, the Investment Manager of Mason Hill Partners, LP
Date:	08/13/2026

Sean M. Fieler

Signature:	/s/ Sean M. Fieler
Name/Title:	Sean M. Fieler
Date:	08/13/2026