2 July 2026

Not for release, publication or distribution, in whole or in part, directly or indirectly, in or into the United States, Australia, Canada, Japan or South Africa or in any other jurisdiction in which the release, publication or distribution would be unlawful or require registration.

This announcement does not constitute an offer to sell or the solicitation of an offer to purchase the securities described herein, nor shall there be any sale of the securities referred to herein in or into any jurisdiction where such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction.

This announcement contains inside information

Proposed secondary placing of ordinary shares in Harbour Energy PLC ("Harbour" or the "Company")

Potomac View Investments, L.P. (the "Seller"), an entity managed by EIG Management Company, LLC ("EIG"), announces its intention to sell approximately 54.8 million ordinary shares in Harbour (the "Placing Shares"), representing approximately 3.5% of the Company's issued share capital, through a placing of ordinary shares to institutional investors (the "Placing"). The completion of the Placing will represent the disposal of EIG's entire residual shareholding in Harbour.

The price per Placing Share and the final number of Placing Shares to be placed will be determined by way of an accelerated bookbuilding process. The bookbuilding period will commence immediately following this announcement and may close at any time on short notice. The results of the Placing will be announced as soon as practicable thereafter.

Barclays Bank PLC is acting as Sole Global Co-ordinator and Sole Bookrunner on the Placing (the "Sole Global Co-ordinator").

The Company is not party to the Placing and will not receive any proceeds from the Placing.

Enquires:

Barclays                                             +44 (0)207623 2323

Sole Global Co-ordinator and Sole Bookrunner

Mike Powell

Chris Madderson

Casey Bandman

Important notices

This announcement is not for distribution, directly or indirectly, in or into the United States (including its territories and possessions, any state of the United States and the District of Columbia, the "United States"), Australia, Canada, Japan or South Africa or any other jurisdiction in which the distribution or announcement would be unlawful. The distribution of this announcement and the offer and sale of the shares in certain jurisdictions may be restricted by law and persons into whose possession this announcement or other information referred to herein comes should inform themselves about and observe any such restriction. Any failure to comply with these restrictions may constitute a violation of the securities laws of any such jurisdiction.

The Placing Shares are not being offered to the public in any jurisdiction and may not be offered to the public in any jurisdiction in circumstances which would require the preparation or registration of any prospectus or offering document relating to the shares in such jurisdiction. This announcement is not a prospectus and does not constitute or form part of any offer or solicitation to purchase or subscribe for securities in the United States, Canada, South Africa, Australia or Japan or any other jurisdiction in which such offers or sales are unlawful. No action has been taken by the Seller, the Sole Global Co-ordinator or any of its affiliates to permit a public offering of the shares or possession or distribution of this announcement in any jurisdiction where action for that purpose is required. Persons into whose possession this announcement comes are required to inform themselves about and to observe any such restrictions.

The securities referred to herein have not been, and will not be, registered under the U.S. Securities Act of 1933, as amended (the "U.S. Securities Act"), or under the securities laws of any state of the United States, and may not be offered or sold, directly or indirectly, in the United States except pursuant to an available exemption from, or in a transaction not subject to, the registration requirements of the U.S. Securities Act and the securities laws of any state or other jurisdiction of the United States. There will be no public offer of securities in the United States or elsewhere.

In member states of the European Economic Area (the "EEA"), this announcement and any offer if made subsequently is directed exclusively at persons who are "qualified investors" within the meaning of article 2(e) of the Prospectus Regulation (Regulation (EU) 2017/1129) ("Qualified Investors").

In the United Kingdom, this announcement and any offer if made subsequently is directed exclusively at persons who are "qualified investors" as defined in paragraph 15 of Schedule 1 to the Public Offers and Admissions to Trading Regulations 2024, and: (i) who have professional experience in matters relating to investments falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the "Order") or (ii) who fall within Article 49(2)(a) to (d) of the Order, or (iii) to whom it may otherwise lawfully be communicated (all such persons together with Qualified Investors in the EEA being referred to herein as "Relevant Persons"). This announcement is directed only at Relevant Persons and must not be acted on or relied on by persons who are not Relevant Persons. Any investment or investment activity to which this announcement relates is available only to Relevant Persons and will be engaged in only with Relevant Persons.

This announcement includes statements that are, or may be deemed to be, forward-looking statements. These forward-looking statements may be identified by the use of forward-looking terminology, including the terms "intends", "expects", "will", or "may", or, in each case, their negative or other variations or comparable terminology, or by discussions of strategy, plans, objectives, goals, future events or intentions. These forward-looking statements include all matters that are not historical facts. No assurances can be given that the forward-looking statements in this announcement will be realised. As a result, no undue reliance should be placed on these forward-looking statements as a prediction of actual results or otherwise.

In connection with the Placing, the Sole Global Co-ordinator and any of its affiliates may take up a portion of the Placing Shares as a principal position and in that capacity may retain, purchase, sell, offer to sell for its own account such shares and other securities of the Company or related investments in connection with the Placing or otherwise. Accordingly, references in this announcement to the Placing Shares being sold, offered, subscribed, acquired, placed or otherwise dealt in should be read as including any issue or offer to, or subscription, acquisition, placing or dealing by, the Sole Global Co-ordinator and any of its affiliates acting in such capacity. In addition, the Sole Global Co-ordinator and any of its affiliates may have entered or may enter into financing arrangements (including swaps or contracts for differences) with investors in connection with which the Sole Global Co-ordinator and any of its affiliates may from time to time acquire, hold or dispose of shares in the Company. The Sole Global Co-ordinator does not intend to disclose the extent of any such investment or transactions otherwise than in accordance with any legal or regulatory obligations to do so.

Any communications that a transaction is or that the book is "covered" (i.e. indicated demand from investors in the book equals or exceeds the amount of the securities being offered) are not any indications or assurances that the book will remain covered or that the transaction and securities will be fully distributed by the Sole Global Co-ordinator. 

Neither the Sole Global Co-ordinator or any of its affiliates or its or its affiliates' directors, officers, employees, advisers or agents, accepts any responsibility or liability whatsoever for or makes any representation or warranty, express or implied, as to the truth, accuracy or completeness of the information in this announcement (or whether any information has been omitted from the announcement) whether written, oral or in a visual or electronic form, and howsoever transmitted or made available or for any loss howsoever arising from any use of this announcement or its contents or otherwise arising in connection therewith. No prospectus or offering document has been or will be prepared in connection with this secondary offering. Any investment decision to buy securities in the secondary offering must be made solely on the basis of publicly available information. Such information is not the responsibility of, and has not been independently verified by, any of the Seller, the Sole Global Co-ordinator or any of its affiliates.

The Sole Global Co-ordinator is acting on behalf of the Seller and no one else in connection with the Placing and will not be responsible to any other person for providing the protections afforded to any of its clients or for providing advice in relation to the Placing.

Barclays Bank PLC, which is authorised by the Prudential Regulation Authority ("PRA") and regulated by the Financial Conduct Authority and the PRA, is acting on behalf of the Seller only in connection with the Placing and no one else, and will not be responsible to anyone other than the Seller for providing the protections offered to clients of Barclays Bank PLC, nor for providing advice in relation to the Placing Shares or the Placing.