NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION IN OR INTO ANY JURISDICTION WHERE IT IS UNLAWFUL TO RELEASE, PUBLISH OR DISTRIBUTE THIS ANNOUNCEMENT.

NOTHING IN THIS ELECTRONIC TRANSMISSION CONSTITUTES AN OFFER TO BUY, AN OFFER OF, OR A SOLICITATION OF AN OFFER TO SELL, SECURITIES IN ANY JURISDICTION IN WHICH SUCH OFFER OR SOLICITATION WOULD BE UNLAWFUL. THE TENDER OFFER REFERRED TO IN THIS ANNOUNCEMENT IS SUBJECT TO OFFER AND DISTRIBUTION RESTRICTIONS IN THE UNITED STATES, THE UNITED KINGDOM, ITALY, FRANCE AND BELGIUM. SEE "OFFER AND DISTRIBUTION RESTRICTIONS" IN THE TENDER OFFER MEMORANDUM.

Nostrum Oil & Gas Finance B.V.

(incorporated under the laws of the Netherlands)

Nostrum Oil & Gas B.V.

(incorporated under the laws of the Netherlands)

TRANSACTION UPDATE AND SUPPLEMENT TO TENDER OFFER MEMORANDUM

Nostrum Oil & Gas Finance B.V. (the "Issuer") and Nostrum Oil & Gas B.V. (the "Offeror") today announce that, on 17 August 2026, Nostrum Oil & Gas PLC (the "Parent" together with its subsidiaries, the "Group") announced via the Regulatory News Service operated by the London Stock Exchange plc that the Issuer had entered into a sale and purchase agreement to sell the Issuer's participating interests in the charter capital of Zhaikmunai LLP and POSITIV Invest LLP (together with the Issuer's rights under certain related loan agreements) to Altaris Holding Ltd., which is owned by Fincraft Energy Holding Limited and Alturion Holding Limited (the "Sale") (the "Announcement").

The Announcement, which can be found here: https://www.londonstockexchange.com/news-article/NOG/agreement-to-sell-kazakhstan-operations/17740760, contains important information, which the holders of the Issuer's senior secured notes (Reg S ISIN: USN64884AF16; Private Placement ISIN: US66978CAF95) (the "Senior Secured Notes") and senior unsecured notes (Reg S ISIN: USN64884AE41; Private Placement ISIN: US66978CAD48) (the "Senior Unsecured Notes", and together with the Senior Secured Notes, the "Notes") should read carefully, including with respect to the Offeror's ongoing tender offer with respect to the Senior Secured Notes which was commenced on 24 July 2026 (the "Tender Offer").

The Offeror considers that the Sale may constitute a material change with respect to the Tender Offer, and the Tender Offer, which was scheduled to expire at 5:00 p.m. (New York City time) on 21 August 2026, has now been extended until 5:00 p.m. (New York City time) on 2 September 2026 (unless amended, modified, extended, terminated and/or withdrawn by the Offeror). Accordingly, all references to "Expiration Date" in the Tender Offer Memorandum shall be read as 5:00 p.m. (New York City time) on 2 September 2026. The Offeror is extending the Tender Offer in order to provide additional time for Eligible Holders to consider the Tender Offer.

Valid Tender Instructions previously received by the Information and Tender Agent and not validly withdrawn do not need to be resubmitted to the Information and Tender Agent.

Eligible Holders that have not yet submitted a valid Tender Instruction, and Eligible Holders who had previously validly withdrawn their Tender Instructions, may still participate in the Tender Offer by following the procedures described in the Tender Offer Memorandum.

Save for the amendment set out above, all other terms and conditions of the Tender Offer as described in the Tender Offer Memorandum remain unchanged.

This announcement does not contain the full terms and conditions of the Tender Offer, which are contained in the Tender Offer Memorandum dated 24 July 2026 prepared by the Offeror (the "Tender Offer Memorandum"). The Tender Offer Memorandum is available to Eligible Holders from GLAS Trust Company LLC (the "Information and Tender Agent") from the date that it is available until the Tender Offer Settlement Date.

Capitalised terms used in this announcement but not defined have the meanings given to them in the Tender Offer Memorandum.

This announcement and the Announcement shall be incorporated into, and form part of, the Tender Offer Memorandum and shall therefore constitute Information Incorporated by Reference.

Contact Information

Requests for additional copies of the Tender Offer Memorandum or related documents and questions relating to the procedures for participating in the Tender Offer should be directed to:

INFORMATION AND TABULATION AGENT

GLAS Trust Company LLC

3 Second Street, Suite 206
Jersey City, New Jersey 07311
United States

Email: [email protected]

Dated: 19 August 2026

LEI of Nostrum Oil & Gas Finance B.V.: 213800SGF6UKA42KSB50

LEI of Nostrum Oil & Gas B.V.: 7245000TZTMGZHEKJ971

Further Information

For further information please visit www.nostrumoilandgas.com

Further Enquiries

Nostrum Oil & Gas PLC                                          

Yelena Zhuravleva, CFO

[email protected]

TEAM LEWIS                                                                                        

Galyna Kulachek

+ 44 (0) 20 7802 2664

[email protected]

About Nostrum Oil & Gas

Nostrum Oil & Gas PLC (the ultimate parent company of the Offeror and the Issuer) is an independent energy company with gas processing infrastructure and an export hub in north-west Kazakhstan. Its shares are listed on the London Stock Exchange (ticker symbol: NOG). The principal producing asset of Nostrum Oil & Gas PLC is the Chinarevskoye field which is operated by its wholly-owned subsidiary Zhaikmunai LLP, which is the sole holder of the subsoil use rights with respect to the development of the Chinarevskoye field. The Company also owns an 80% interest in Positiv Invest LLP, which holds the subsoil use rights for the "Kamenskoe" and "Kamensko-Teplovsko-Tokarevskoe" areas in the West Kazakhstan region (the Stepnoy Leopard fields).

Forward-Looking Statements

Some of the statements in this announcement are forward-looking. Forward-looking statements include statements regarding the intent, belief and current expectations of the Group or its officers with respect to various matters. When used in this announcement, the words "expects", "believes", "anticipates", "plans", "may", "will", "should" and similar expressions, and the negatives thereof, are intended to identify forward-looking statements. Such statements are not promises nor guarantees and are subject to risks and uncertainties that could cause actual outcomes to differ materially from those suggested by any such statements.

No part of this announcement constitutes, or shall be taken to constitute, an invitation or inducement to invest in the Group or any other entity, and shareholders of the Group are cautioned not to place undue reliance on the forward-looking statements. Save as required by the relevant listing rules and applicable law, the Group does not undertake to update or change any forward-looking statements to reflect events occurring after the date of this announcement.

DISCLAIMER

This announcement must be read in conjunction with the Tender Offer Memorandum. This announcement and the Tender Offer Memorandum contain important information which each holder of the Senior Secured Notes should read carefully before making a decision with respect to the Tender Offer. If you are in any doubt as to the action you should take, you are recommended to seek your own financial and legal advice regarding the consequences (financial, legal, tax or otherwise) of the Tender Offer immediately from your stockbroker, bank manager, solicitor, accountant or other independent financial, legal or tax adviser. Any individual or company whose Senior Secured Notes are held on its behalf by a broker, dealer, bank, custodian, trust company or other nominee or intermediary must contact such entity immediately if they wish to participate in the Tender Offer.

Each Eligible Holder is solely responsible for making its own independent appraisal of all matters as such Eligible Holder deems appropriate to make its own decision whether or not to participate in the Tender Offer.

In accordance with normal practice, none of the Trustee, the Security Trustee, the Information and Tender Agent or the Registrar, nor any of their respective directors, officers, employees, agents or affiliates expresses any opinion on the merits of, makes any representation or recommendation whatsoever regarding, or shall be liable for, the Tender Offer or the Tender Offer Memorandum. None of the Trustee, the Security Trustee, the Information and Tender Agent or the Registrar, nor any of their respective directors, officers, employees, agents or affiliates have been involved in formulating the Tender Offer or the Tender Offer Memorandum and makes no representation or warranty with respect to the accuracy, validity, correctness or completeness of the Tender Offer Memorandum or any other documents proposed in connection therewith.

Before making a decision with respect to the Tender Offer, Senior Secured Noteholders should carefully consider all of the information in the Tender Offer Memorandum and, in particular, the risk factors described in the section entitled "Risk Factors and Other Considerations" in the Tender Offer Memorandum.