Transaction Update & Tender Offer Supplement

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until 5:00 p.m. (New York City time) on 2 September 2026 (unless amended, modified, extended, terminated and/or withdrawn by the Offeror).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Valid Tender Instructions previously received by the Information and Tender Agent and not validly withdrawn do not need to be resubmitted to the Information and Tender Agent.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Holders that have not yet submitted a valid Tender Instruction, and Eligible Holders who had previously validly withdrawn their Tender Instructions, may still participate in the Tender Offer by following the procedures described in the Tender Offer Memorandum.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.

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.

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

Dated: 19 August 2026

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

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