Mandatory Purchase of SUNs and Initial Cash Amount

NOTICE OF MANDATORY PURCHASE OF SENIOR UNSECURED NOTES AND INITIAL CASH AMOUNT

Nostrum Oil & Gas PLC (the "Company", and together with its subsidiaries, the "Group") announced via RNS on 16 October 2026 (the "Announcement") that the Company's indirect subsidiary, Nostrum Oil & Gas Finance B.V. (the "Issuer"), had completed the sale of its Kazakhstan operations (the "Sale") pursuant to a sale and purchase agreement (the “SPA”) and that the Issuer would give notice to the holders (the "Noteholders") of its Senior Unsecured Notes due 2028 (the "Notes") in respect of the mandatory purchase of the Notes. The Announcement is available at: https://www.londonstockexchange.com/news-article/NOG/sale-of-kazakhstan-operations-redemption-of-ssns/17838615.

Final Interest Payment

The Company announces that on or about 26 October 2026, the Issuer will pay a final interest payment of U.S.$ 3,018,885.76 on the Notes (the “Final Interest Payment”) for the period from (and including) 30 June 2026 to (but excluding) 15 October 2026 (the "Completion Effective Date").

Initial Payment

In accordance with the Company’s announcement via RNS on 8 September 2026, after the Final Interest Payment has been made, within 10 business days from the Completion Effective Date, Nostrum Oil & Gas B.V. ("NOG BV") is due to effect a purchase of U.S.$417,523,273 in principal amount of Notes (the "Initial Payment").

The Company announces that on or around 29 October 2026, NOG BV will pay a total cash amount of U.S.$170,000,000 at a price of U.S.$0.40716 per U.S.$1 in principal amount in respect of the Initial Payment.

After the Initial Payment has been made, the aggregate principal amount of the Notes that will remain outstanding will be U.S.$100,000,000 and the Group will have cash and cash equivalents available to it in the amount of approximately U.S.$45.5 million, which have been retained by the Group including for the following purposes:

funding the managed wind-down costs of approximately U.S.$27.5 million, as detailed in the managed wind-down budget prepared in consultation with the third-party adviser, FRP Advisory Trading Limited;

payment of third-party and contingent liabilities in an amount of approximately U.S.$17.0 million (including transaction costs relating to the Sale); and

reserved solvency guarantee amount of $1.0 million.

U.S.$10.0 million of consideration paid in connection with the Sale is held in an escrow account in accordance with the terms of the SPA.

The cash balances of the disposed entities (Zhaikmunai and POSITIV Invest) at 23.59 hours London time on the day before the completion date was approximately U.S.$6.2 million which remains receivable by the Group as a net cash adjustment in accordance with the terms of the SPA.

Dated: 20 October 2026

Person Responsible