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

THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION

Nostrum Oil & Gas Finance B.V.

(incorporated under the laws of the Netherlands)

CONSENT SOLICITATION

Nostrum Oil & Gas Finance B.V. (the "Issuer") today announces its invitations to eligible holders of the following Notes to approve as a resolution in writing, or to the extent that is not achieved, at a meeting of the holders of the Notes (the "Meeting"), the Extraordinary Resolution set out in the Notice delivered to the Clearing System for communication to Direct Participants.

This announcement does not contain the full terms and conditions of the Consent Solicitation, which are contained in the Consent Solicitation Memorandum dated 8 September 2026 prepared by the Issuer (the "Consent Solicitation Memorandum"). The Consent Solicitation Memorandum and the Notice are available to eligible holders from GLAS Trust Company LLC (the "Information and Tabulation Agent") from the date that they are available until 5 Business Days after the Completion Effective Date.

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

Background to the Consent Solicitation

The Sale

On 17 August 2026, Nostrum Oil & Gas PLC (the "Parent", and together with its subsidiaries, the "Group") announced via RNS that the Parent's indirect subsidiary, the Issuer, had entered into an SPA pursuant to which the Issuer had agreed to sell and Altaris Holding Ltd. (the "Purchaser") had agreed to buy the Issuer's participating interests in the charter capital of Zhaikmunai LLP and POSITIV Invest LLP (the "Targets" and together with their respective subsidiaries, the "Target Group") (together with the Issuer's rights under certain agreements evidencing the terms of the intra-group liabilities between the Issuer and the Target Group), subject to certain conditions precedent that are more particularly described below (the "Sale").

The total consideration for the Sale will be U.S.$304,600,000, subject to certain adjustments that may be made in relation to the net working capital and the net debt and cash positions of the Target Group on completion under and in accordance with the SPA ("Completion").

If the conditions precedent to the Sale are satisfied and the Sale completes, the Group expects to repay the Issuer's Senior Secured Notes due 2026 (the "Senior Secured Notes") in full at their outstanding principal amount (plus any accrued and unpaid interest to the date fixed for redemption and any default interest) and the Notes in part at less than their outstanding principal amount (but expects to pay accrued and unpaid interest with respect to all of the Notes up to the Completion Effective Date).

The Parent considers that, in light of the recent maturity of the Senior Secured Notes and the Notes on 30 June 2026 and the Group being unable to repay the amounts due under the Senior Secured Notes and the Notes at that time, the Transaction described in the Consent Solicitation Memorandum will result in the best outcome for the Group and its stakeholders reasonably available in the circumstances.

Conditions to the Sale

The Sale is subject to various conditions precedent, including (but not limited to) merger control clearance pursuant to applicable Kazakhstan law, consents and waivers from the Ministry of Energy of the Republic of Kazakhstan and Qazaq Gaz, applicable shareholder and pre-emption processes in relation to POSITIV Invest LLP, approval of the waivers in respect of and the modifications to the Notes (as more particularly described in the Consent Solicitation Memorandum, the "Proposals") and confirmed financing for the Purchaser.

The SPA provides for a long-stop date of 15 September 2026 by which the conditions precedent to the Sale must be satisfied or waived. The long-stop date may be extended automatically once, for a period of two months, if the conditions precedent have not been satisfied or waived by 15 September 2026.

The Sale is not conditional on and does not require the approval of the Parent's shareholders.

Potential Issuer liability under the SPA and related escrow arrangements

It has been agreed between the Issuer and the Purchaser that U.S.$10,000,000 of the Sale consideration will, following Completion, be held in an escrow account in connection with any potential claims under or in connection with the SPA for a period of at least six months.

Releases required in connection with the Sale

At Completion, certain agreements will become effective to release of (a) the guarantees and security in respect of the Notes, in each case provided by the Targets and any of their respective direct or indirect subsidiaries, as applicable, (b) any Shared Security provided by any member of the Group over any Intra-Group Liabilities owed by the Targets and/or any of their respective direct or indirect subsidiaries, as applicable, and (c) the guarantees and security in respect of the Senior Secured Notes.

Senior Secured Noteholder and Noteholder recoveries on or about Completion

If the conditions precedent to the Sale are satisfied and the Sale completes, at Completion the Group expects to repay the Senior Secured Notes in full at their outstanding principal amount (plus any accrued and unpaid interest to the date fixed for redemption and any default interest). Assuming that Completion occurs on 30 September 2026, approximately U.S.$243,864,658.75^[1] would be required to repay the Senior Secured Notes in full.

As the Senior Secured Notes would be repaid in full, no approval of the Senior Secured Noteholders is being sought by the Issuer pursuant to the Consent Solicitation Memorandum or otherwise.

If the conditions precedent to the Sale are satisfied and the Sale completes, the Group expects to repay the Notes in part at less than their outstanding principal amount.

The Issuer will make payment of interest in respect of the period from (and including) 30 June 2026 to (but excluding) the Completion Effective Date pursuant to Condition 7 of the Notes as soon as reasonably practicable after the Completion Effective Date and in any case within 7 Business Days from the Completion Effective Date (the "Final Interest Payment"). By way of example, if Completion occurs on 30 September 2026, approximately U.S.$2,587,616.37 in interest on the Notes (in respect of the period from (and including) 30 June 2026 to (but excluding) the Completion Effective Date) would be paid to Noteholders. Accordingly, if Completion occurs, there will be no interest that has accrued up to the Completion Effective Date that will remain outstanding. As from the Completion Effective Date the interest rate applicable to the Notes will be 0%.

In accordance with Condition 8 of the Notes (as would be amended pursuant to the Consent Solicitation), after the Final Interest Payment has been made, Nostrum Oil & Gas B.V. ("NOG BV") will effect a purchase in respect of U.S.$417,523,273 in principal amount of Notes within 10 Business Days from the Completion Effective Date (the "Initial Payment"), such that after the Initial Payment, the aggregate principal amount of Notes that will remain outstanding will be U.S.$100,000,000. The total cash amount paid by NOG BV (and therefore the price at which NOG BV will purchase the applicable Notes) will be set by reference to the Cash and Cash Equivalents^[2] available to the Group at that time, after taking into account certain deductions. The Issuer will provide a further update on the amount, price and timing of the Initial Payment in due course.

For the avoidance of doubt, the redemptions, payments purchases described above shall also apply to the U.S.$15,594,000 in principal amount of Senior Secured Notes and U.S.$33,012,515 in principal amount of Notes held in the Holding Period Trust which was established as part of the financial restructuring undertaken by the Issuer and completed in February 2023, and is expected to expire on or before 9 February 2028. As at the date hereof, the cash sat within the Holding Period Trust is U.S.$4,620,274.46.

Following the Completion Effective Date, the maturity date of the Notes will be extended from 30 June 2026 to 31 December 2028, and any and all Defaults or Events of Default that existed as a result of the Issuer's (and the Guarantors') failure to redeem the Notes at their principal amount on 30 June 2026 will be waived and, for the avoidance of doubt, the long-term standstill agreed in connection with the consent solicitation memorandum dated 26 June 2026 shall therefore cease to operate.

Managed Wind-Down

As the Group will no longer continue to own an operating business after the Sale, and as the Group would, but for the approvals sought in the Consent Solicitation Memorandum, thereafter no longer be capable of effecting repayment of the full principal amount of the Notes that would remain outstanding, the Group will as soon as reasonably practicable following Completion pursue a managed wind-down of the Group's business and an orderly liquidation or dissolution (or analogous concept under the laws of any applicable jurisdiction) of each member of the Group, with the intention that each member of the Group shall pay in full all of its liabilities and that such liquidation or dissolution (or analogous concept under the laws of any applicable jurisdiction) shall be on a solvent basis (the "Managed Wind-Down").

In connection with the Sale and the Managed Wind-Down, the consents and approvals sought in the Consent Solicitation Memorandum provide a mechanism for the principal amount of Notes to be adjusted and repurchased or repaid, subject to and based on the level of Cash and Cash Equivalents that are available to the Group from time to time to make such payments, after factoring in the remaining Managed Wind-Down Costs^[3] in accordance with the Managed Wind-Down Budget^[4], any Third Party Liabilities^[5] and a Solvency Guarantee Amount^[6].

The Group expects that the Managed Wind-Down would involve the realisation of any assets with a view to repaying principal amounts of the Notes to the extent possible via a mandatory cash sweep (as would be included in Condition 8 pursuant to the Consent Solicitation). This will require the Group to test Cash and Cash Equivalents available to the Group monthly and, after taking into account applicable deductions and provisions, if available Cash and Cash Equivalents exceeds U.S.$5,000,000, such amounts must be applied to purchase the Notes at par.

Once the Parent considers (acting in its sole and absolute discretion and acting in good faith) that all assets of the Group which are capable (on a commercially reasonable basis) of being realised for available cash, have been so realised, and provided that all such cash proceeds will be applied in effecting such purchase, NOG BV shall be entitled to repurchase the remaining principal amount of Notes at any price, provided that all available Cash and Cash Equivalents at that time are used in effecting such purchase (other than any Cash and Cash Equivalents required to be retained to fund the remaining Managed Wind-Down Costs in accordance with the Managed Wind-Down Budget and any remaining Third Party Liabilities).

In practice, the Group expects that the Managed Wind-Down would involve a bottom-up approach, with subsidiaries being wound down first and any residual assets and distributions flowing upward through the Group structure.

The Group is continuing to prepare its Managed Wind-Down Budget and carry out diligence in respect of, amongst other things, its Third Party Liabilities; however, at the date of this announcement, the Group estimates (but provides no assurance) that:

(i)         its Managed Wind-Down Costs will be approximately U.S.$30,000,000;

(ii)         its Third Party Liabilities will be approximately U.S.$10,000,000;

(iii)        its Sale-related fees, costs and expenses, including financial adviser fees, legal fees, Trustee and Security Trustee fees, costs and expenses (including related legal fees) will be approximately U.S.$10,000,000;

(iv)        the Ad Hoc Forum Work Fee (described below) will be U.S.$5,000,000; and

(v)        the initial Solvency Guarantee Amount will be U.S.$1,000,000.

The Board of Directors of the Parent acknowledges the importance of monitoring the Group's ongoing costs and will continue to keep the options available to the Group under review.

While the Sale is not conditional on and does not require the approval of the Parent's shareholders, nor would any delisting require the approval of the Parent's shareholders, shareholder approval is expected to be required in connection with the Managed Wind-Down of the Parent pursuant to the Insolvency Act 1986.

The Group does not currently expect that residual proceeds available for distribution to shareholders of the Parent will be material, if any. However, the Group does not rule out the possibility of a final distribution to shareholders at the end of the Managed Wind-Down, which would most likely derive from contingencies reserved for payment of the final Managed Wind-Down Costs not in fact being required.

Ad Hoc Forum and Ad Hoc Forum Work Fee

The Group has been in discussions with an ad hoc forum of beneficial owners of the Notes (who currently hold in aggregate more than 50% in principal amount of the Notes outstanding) (the "Ad Hoc Forum") regarding the Sale, the Managed Wind-Down and the Consent Solicitation, and the Ad Hoc Forum has expressed its support in respect of all such matters.

The Ad Hoc Forum have been working alongside the Group for some time to assist with facilitating and negotiating the Sale such that holders of the Senior Secured Notes and the Notes are able to realise a positive outcome with respect to their investment following the Group's financial restructuring in 2023. Accordingly, the Parent has agreed to pay a work fee in the amount of U.S.$5,000,000 to the Ad Hoc Forum should Completion occur (the "Ad Hoc Forum Work Fee").

SAP

The Group proposes to put in place a strategic alignment plan (the "SAP") to reward officers, directors and/or employees of members of the Group in connection with (i) the Sale, the minimum and maximum aggregate payments under such strategic alignment plan being U.S.$7,000,000 and U.S.$8,000,000, respectively, such SAP being approved by the Board of Directors of the Parent and (ii) the Managed Wind-Down, such SAP being prepared in consultation with the Ad Hoc Forum and approved by the Board of Directors of the Parent.

The SAP is intended to align the interests of those officers, directors and/or employees with the interests of the Senior Secured Noteholders and Noteholders in maximising value from the Sale and the Managed Wind-Down.

No amounts under the SAP will be paid before the Senior Secured Notes have been repaid in full and the Initial Payment has been made. It is expected that a payment of approximately 75% of the Sale-related SAP amount will be made shortly after the Senior Secured Notes have been repaid in full and the Initial Payment has been made.

There can be no assurance that the Sale will complete

If the Sale does not complete, the Completion Consent Conditions will not be satisfied and no changes will be made to the terms of the Notes. Accordingly, the maturity date of the Notes will remain 30 June 2026, although the long-term standstill agreed in connection with the consent solicitation memorandum dated 26 June 2026 will continue to apply.

Under the SPA, the Purchaser has agreed, subject to Completion, to assume the commercial risk associated with the ongoing withholding tax cases in Kazakhstan concerning the Target Group. If the Sale does not complete, those risks will remain with the Group.

Conditions

The consummation of the modifications with respect to the Notes are conditional on certain matters, including that Completion in respect of the Sale shall have occurred (the "Completion Consent Conditions").

The Issuer anticipates that, promptly after the Completion Consent Conditions are satisfied, the relevant documentation (the "Completion Consent Documents") to reflect the modifications with respect to the Notes will be entered into by the parties thereto (the date that such Completion Consent Documents are entered into by the parties thereto, being the "Completion Effective Date").

Indicative Timetable

The following table sets forth the expected dates and times of the key events relating to the Consent Solicitation. The dates and times below are indicative only. The below times and dates as they relate to the Consent Solicitation are subject to the right of the Issuer, in its sole discretion, to amend, extend and/or terminate the Consent Solicitation at any time (subject to applicable law and save as set out in the Consent Solicitation Memorandum). Accordingly, the actual timetable may differ significantly from the indicative timetable below.

Unless stated otherwise, announcements will be made by the Issuer to all relevant stock exchanges and delivered to the Clearing System for communication to Direct Participants. Copies of the announcements will also be made available to eligible holders upon request from the Information and Tabulation Agent from the date that they are available until 5 Business Days after the Completion Effective Date.

Noteholders are advised to check with any bank, securities broker or other intermediary through which they hold Notes when such intermediary would require to receive instructions from a Noteholder in order for that Noteholder to be able to participate in the Consent Solicitation before the deadlines specified above and in the Consent Solicitation Memorandum. The deadlines set by any such intermediary and the Clearing System for the submission of Consent Instructions may be earlier than the relevant deadlines specified above and in the Consent Solicitation Memorandum.

Contact Information

Requests for copies of this announcement, the Consent Solicitation Memorandum or related documents and questions relating to the procedures for voting in respect of the Extraordinary Resolution 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: 8 September 2026

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

Person Responsible

The person responsible for arranging the release of this announcement on behalf of the Issuer is Robin Storey, Chief Legal Officer and Company Secretary.

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 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 Parent 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 has been prepared by the Issuer exclusively for information purposes. It does not constitute or include any advice or recommendation by the Issuer (or any other person) regarding the securities of the Issuer or as to the merits of any transaction or the making of any investment decision. Neither this announcement nor the Consent Solicitation Memorandum constitutes an invitation to participate in the Proposals in any jurisdiction in which, or to any person to whom, it is unlawful to make such invitation or for there to be such participation under applicable securities laws.

This announcement must be read in conjunction with the Consent Solicitation Memorandum. This announcement, the Consent Solicitation Memorandum and the Notice contain important information which each holder of the Notes should read carefully before making a decision with respect to the Proposals. 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 Consent Solicitation immediately from your stockbroker, bank manager, solicitor, accountant or other independent financial, legal or tax adviser. Any individual or company whose 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 Consent Solicitation.

Each Noteholder is solely responsible for making its own independent appraisal of all matters as such Noteholder deems appropriate to make its own decision whether or not to participate in the Consent Solicitation.

In accordance with normal practice, none of the Trustee, the Security Trustee, the Information and Tabulation 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 Proposals, the Extraordinary Resolution, the Consent Solicitation or the Consent Solicitation Memorandum. None of the Trustee, the Security Trustee, the Information and Tabulation Agent or the Registrar, nor any of their respective directors, officers, employees, agents or affiliates have been involved in formulating the Proposals, the Extraordinary Resolution, the Consent Solicitation or the Consent Solicitation Memorandum and makes no representation or warranty with respect to the accuracy, validity, correctness or completeness of the Consent Solicitation Memorandum or any other documents proposed in connection therewith.

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

The distribution of this announcement in certain jurisdictions may be restricted by laws and regulations (including Sanctions). Persons into whose possession this announcement comes are required by the Issuer, the Guarantors, the Trustee, the Security Trustee, the Information and Tabulation Agent and the Registrar to inform themselves about, and to observe, any such restrictions.