GTE Gran Tierra Energy Inc.

FORM 8.3

PUBLIC OPENING POSITION DISCLOSURE/DEALING DISCLOSURE BY

A PERSON WITH INTERESTS IN RELEVANT SECURITIES REPRESENTING 1% OR MORE

Rule 8.3 of the Takeover Code (the "Code")

1.         KEY INFORMATION

2.         POSITIONS OF THE PERSON MAKING THE DISCLOSURE

If there are positions or rights to subscribe to disclose in more than one class of relevant securities of the offeror or offeree named in 1(c), copy table 2(a) or (b) (as appropriate) for each additional class of relevant security.

(a)        Interests and short positions in the relevant securities of the offeror or offeree to which the disclosure relates following the dealing (if any)

All interests and all short positions should be disclosed.

Details of any open stock-settled derivative positions (including traded options), or agreements to purchase or sell relevant securities, should be given on a Supplemental Form 8 (Open Positions).

(b)        Rights to subscribe for new securities (including directors' and other employee options)

3.         DEALINGS (IF ANY) BY THE PERSON MAKING THE DISCLOSURE

Where there have been dealings in more than one class of relevant securities of the offeror or offeree named in 1(c), copy table 3(a), (b), (c) or (d) (as appropriate) for each additional class of relevant security dealt in.

The currency of all prices and other monetary amounts should be stated.

(a)        Purchases and sales

(b)        Cash-settled derivative transactions

(c)        Stock-settled derivative transactions (including options)

(i)         Writing, selling, purchasing or varying

(ii)        Exercise

(d)        Other dealings (including subscribing for new securities)

4.         OTHER INFORMATION

(a)        Indemnity and other dealing arrangements

(b)        Agreements, arrangements or understandings relating to options or derivatives

(c)        Attachments

Public disclosures under Rule 8 of the Code must be made to a Regulatory Information Service.

The Panel's Market Surveillance Unit is available for consultation in relation to the Code's disclosure requirements on +44 (0)20 7638 0129.

*If the discloser is a natural person, a telephone number does not need to be included, provided contact information has been provided to the Panel's Market Surveillance Unit.

The Code can be viewed on the Panel's website at www.thetakeoverpanel.org.uk.

*Previous dates of dealing