Proposed Tender Offer & Notice of General Meeting

Niox Group PLC

29 September 2026

THIS ANNOUNCEMENT AND THE INFORMATION CONTAINED HEREIN (TOGETHER THIS "ANNOUNCEMENT") IS RESTRICTED AND IS NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, DIRECTLY OR INDIRECTLY, IN WHOLE OR IN PART, INTO OR FROM THE UNITED STATES OF AMERICA, AUSTRALIA, NEW ZEALAND, CANADA, THE REPUBLIC OF SOUTH AFRICA, JAPAN, SINGAPORE, SWITZERLAND OR ANY OTHER JURISDICTION WHERE, OR TO ANY OTHER PERSON TO WHOM, TO DO SO MIGHT CONSTITUTE A VIOLATION OR BREACH OF ANY APPLICABLE LAW OR REGULATION ("RESTRICTED JURISDICTION"). PLEASE SEE THE IMPORTANT NOTICES AT THE END OF THIS ANNOUNCEMENT.

THE INFORMATION CONTAINED WITHIN THIS ANNOUNCEMENT IS DEEMED TO CONSTITUTE INSIDE INFORMATION AS STIPULATED UNDER THE MARKET ABUSE REGULATIONS (EU) NO. 596/2014 WHICH FORMS PART OF UK LAW BY VIRTUE OF THE EUROPEAN UNION (WITHDRAWAL) ACT 2018, AS AMENDED. UPON THE PUBLICATION OF THIS ANNOUNCEMENT, THIS INSIDE INFORMATION IS NOW CONSIDERED TO BE IN THE PUBLIC DOMAIN.

NIOX GROUP PLC

("NIOX"or the"Company"and, together with its subsidiaries, the “Group")

Proposed return of up to £12.5 million by way of a purchase of up to 15,625,000 Ordinary Shares at 80 pence per share pursuant to a Tender Offer

and

Notice of General Meeting

Oxford, UK – 29 September 2026:NIOX Group plc (AIM: NIOX), a medical device company focused on point-of-care FeNO testing for the diagnosis, monitoring and management of asthma and COPD, announces that it is proposing to return up to £12.5 million to Shareholders by way of a Tender Offer pursuant to which Qualifying Shareholders are invited to tender some, or all, of their Ordinary Shares at the Tender Price of 80 pence per Ordinary Share. The Tender Offer is for a maximum of 15,625,000 Ordinary Shares.

The Tender Price represents a premium of22.0 per cent. to the mid-market closing price on the Latest Practicable Date being 65.6 pence per Ordinary Share, and a premium of 26.9per cent. to the volume weighted average price of 63.1 pence per Ordinary Share over the three months prior to the Latest Practicable Date.

If the maximum number of Ordinary Shares under the Tender Offer is acquired, this will result in the purchase of approximately 3.7 per cent. of the Company's Issued Ordinary Share Capital as at the Latest Practicable Date.

Qualifying Shareholders are not required to tender any or all of their Ordinary Shares if they do not wish to do so. Qualifying Shareholders who participate in the Tender Offer have a Basic Entitlement to tender approximately 3.7 per cent. of the Ordinary Shares held by them at the Tender Offer Record Date, rounded down to the nearest whole number.Qualifying Shareholders will also have the opportunity to sell an Individual Excess Tender to the extent that other Shareholders tender less than their Basic Entitlement.The Tender Offer isbeingmade available to all Qualifying Shareholders who are on the Register atthe Tender Offer Record Date.

The Tender Offer is being effected by Singer Capital Markets Securities Limited ("Singer Capital Markets"), the Company's corporate broker, as principal on the basis that all Ordinary Shares that it buys under the Tender Offer will be subsequently repurchased from it by the Company pursuant to the terms of a Repurchase Agreement. All Ordinary Shares purchased by the Company from Singer Capital Markets will be cancelled.

The Company expects to post a circular to Shareholders (the "Circular") later today and a copy of the Circular will be published on the Company's website at www.investors.niox.com. The Circularwill set out the background to, and reasons for, the Tender Offer and why the Directors believe the Tender Offer to be in the best interests of the Company and its Shareholders as a whole. The Circular will also contain details on the procedure that should be followed by those Qualifying Shareholders who wish to participate in the Tender Offer.A Form of Proxy and Tender Form for use by Shareholders who hold their Ordinary Shares in certificated form in connection with the Tender Offer is also being despatched with the Circular.

The implementation of the Tender Offer requires Shareholder approval by way of a special resolution (the "Tender Offer Resolution"). The Tender Offer Resolution will be proposed at the General Meeting of the Company to be held at Magdalen Centre, 1 Robert Robinson Ave, The Oxford Science Park, Oxford, OX4 4GA at 11:00 a.m. on 21 October 2026.

The Board is making no recommendation to Qualifying Shareholders in relation to their participation in the Tender Offer. However, the Board is unanimously recommending Shareholders to vote in favour of the Tender Offer Resolution to be proposed at the General Meeting, as the Directors intend to do in respect of their own beneficial holdings of shares.

This summary should be read in conjunction with the full text of this announcement and the Circular. Capitalised terms used but not defined in this announcement will have the same meaning given to them in the Circular.

The person responsible for arranging the release of this announcement on behalf of the Company is Sarah Duncan, Chief Financial Officer.

Contacts

NIOX Group plc Jonathan Emms, Chief Executive Officer Sarah Duncan, Chief Financial Officer	+44 (0) 3303 309 356
Singer Capital Markets (Nominated Adviser and Broker) Jen Boorer / James Fischer / Dan Ingram	+44 (0) 20 7496 3000

About NIOX

Our mission is to improve the diagnosis, monitoring and management of both asthma and COPD by increasing access to FeNO testing. Asthma and COPD are two of the world’s biggest healthcare issues, affecting more than 600 million people combined, many of whom are undiagnosed or misdiagnosed. NIOX is the market leader in point-of-care FeNO testing. The Group designs, develops, and commercialises medical devices to measure FeNO, a precise biomarker for type-2 airway inflammation present in asthma and COPD. NIOX® products are widely used by healthcare professionals to improve the diagnosis, monitoring and management of asthma and COPD. NIOX®devices are the device of choice by leading clinical research organisations for respiratory studies.

NIOX provides products and services through its direct sales organisation and extensive distributor network across more than 50 countries. For more information, please visitwww.niox.com

EXPECTED TIMETABLE OF PRINCIPAL EVENTS

Announcement of the Tender Offer and publication of this Circular and Notice of General Meeting	29 September 2026
Tender Offer opens	30 September 2026
Latest time and date for receipt of Forms of Proxy and electronic voting instructions	11.00 a.m. on 19 October 2026
Latest time and date for receipt of Tender Forms and settlement of TTE instructions and share certificates in relation to the Tender Offer (i.e. close of Tender Offer)	1.00 p.m. on 20 October 2026
Tender Offer Record Date	6.00 p.m. on 20 October 2026
General Meeting	11.00 a.m. on 21 October 2026
Announcement of results of the Tender Offer	7.00 a.m. on 22 October 2026
Purchase of Ordinary Shares under the Tender Offer	23 October 2026
CREST accounts credited for revised, uncertificated holdings of Ordinary Shares (or, in the case of unsuccessful tenders, for entire holdings of Ordinary Shares)	by 27 October 2026
CREST accounts credited in respect of Tender Offer proceeds for uncertificated Ordinary Shares	by 27 October 2026
Despatch cheques in respect of Tender Offer proceeds for certificated Ordinary Shares	by 3 November 2026
Return of share certificates in respect of unsuccessful tenders of certificated Ordinary Shares	by 3 November 2026
Despatch of balancing share certificates (in respect of certificated Ordinary Shares) for revised, certificated holdings in the case of partially successful tenders	by 3 November 2026

All times are references to London times and are indicative only and may change. Each of the above times and dates is based on the Company's expectations as at the date of the Circular and are indicative only and may be changed by the Company (subject to any applicable requirements of the AIM Rules, law and/or the Company constitution). If any of the above times and/or dates change, the revised times and/or dates will be notified to Shareholders by an announcement through a Regulatory Information Service.

ADDITIONAL INFORMATION

Background to and reasons for the Tender Offer

On 29 September 2026, the Company announced its interim results for the six months ended 30 June 2026, in which it announced that the Group delivered a resilient first half performance despite an exceptionally strong comparative period with revenues of £24.0 million (H1 2025: £25.2 million). The business made a profit at an adjusted EBITDA level of £8.3 million (H1 2025: £9.2 million). The Group’s cash position (including cash and cash equivalents) was £16.8 million as at 30 June 2026 (31 December 2025: £19.9 million) following the payment of a £6.5 million dividend in June 2026. Cash generated from operations during the period aggregated £3.9 million (H1 2025: £7.0 million), primarily reflecting the build-up of the new NIOX PRO® inventory ahead of the device's commercial global rollout.

The Group’s strong cash generation and robust balance sheet underpins the Board’s decision to recommend a further return of capital by way of a Tender Offer to return £12.5 million to shareholders.

As previously announced, NIOX’s stated intention is to return 80% of free cash flow to shareholders in the medium term, through ordinary dividend payments and additional cash returns. Looking forward, the Board will continue to assess ongoing opportunities to return capital to shareholders, alongside the capital needs of the Group, through the remainder of the current financial year and into FY27.

Should the company generate additional excess cash beyond its current requirements, the company will consider whether a share repurchase programme, under which, pursuant to existing authorities, the company may repurchase its own shares, would also be appropriate in line with its stated capital allocation policy.

As at 31 August 2026, the Company had approximately £17.4 million in cash and no debt. Subject to the passing of the Tender Offer Resolution by Shareholders at the General Meeting, the Directors will give Qualifying Shareholders the opportunity to tender their Ordinary Shares through the Tender Offer for cash. Each Qualifying Shareholder will be entitled to sell up to approximately 3.7 per cent. of the Ordinary Shares registered in their name on the Register as at the Tender Offer Record Date (the "Basic Entitlement"), rounded down to the nearest whole number of Ordinary Shares under the Tender Offer.

The Tender Offer Resolution will give the Directors authority to distribute £12.5 million to Shareholders through the Tender Offer at the Tender Price.

The Board has considered the various options for returning cash in excess of the Company’s foreseeable future investment needs to Shareholders. The Board has determined that the Tender Offer would be the most appropriate method of returning capital to Shareholders in a quick and efficient manner, taking into account the relative costs, complexity and timeframes of the possible methods available, as well as the likely tax treatment for and equality of treatment of all Shareholders.

In particular, the Board considers the Tender Offer to be beneficial to Shareholders as a whole, because:

1. the Tender Offer is available to all Qualifying Shareholders regardless of the size of their holding;
2. the Tender Price represents a premium of approximately 22.0 per cent. to the mid-market closing price of an Ordinary Share on the Latest Practicable Date being 65.6 pence;
3. the Tender Offer provides Qualifying Shareholders who wish to reduce their holdings of Ordinary Shares with an opportunity to do so at a market-driven price with a premium at the Latest Practicable Date;
4. the Tender Offer enables Ordinary Shares to be sold free of commissions or charges that would otherwise be payable if Qualifying Shareholders were to sell Ordinary Shares through their broker;
5. the Tender Offer will reduce the number of Ordinary Shares in issue, and, assuming earnings stay the same, should have a positive impact on the Company’s earnings per share as the Company intends to cancel all Ordinary Shares acquired in connection with the Tender Offer;
6. the Tender Offer provides Qualifying Shareholders with the choice of whether or not they wish to tender all, part or none of their respective Basic Entitlements and thus permits Shareholders who wish to retain their current investment in the Company in Ordinary Shares to do so; and
7. the Tender Offer will allow the Company to broaden the return of cash to include those Qualifying Shareholders whose Ordinary Shares might not otherwise be purchased by the Company through a general on-market buy back.

Structure of the Tender Offer

The Tender Offer will be implemented on the basis of Singer Capital Markets, as principal, acquiring the successfully tendered Ordinary Shares at the Tender Price (with such acquisitions being market purchases in accordance with the provisions of the Companies Act 2006 and the rules of the London Stock Exchange and the FCA). Immediately following completion of the Tender Offer and if the put and call option under the Repurchase Agreement is exercised, Singer Capital Markets shall sell such Ordinary Shares to the Company at the Tender Price, pursuant to the Repurchase Agreement. These acquisitions by the Company will also be market purchases in accordance with the provisions of the Companies Act 2006 and the rules of the London Stock Exchange and the FCA. It is expected that Qualifying Shareholders which hold their shares in uncertificated form and who successfully tender their Ordinary Shares will receive payment for such Ordinary Shares by 27 October 2026 via the CREST system. Certificated Qualifying Shareholders who successfully tender their Ordinary Shares will have cheques in respect of their consideration despatched to their registered address on 3 November 2026. The Company intends to cancel any repurchased Ordinary Shares immediately.

The Tender Offer will be open to all Shareholders on the Register on the Tender Offer Record Date, save for those who are Shareholders subject to the securities laws of a Restricted Jurisdiction. Qualifying Shareholders must consider carefully all of the information contained in the Circular as well as their personal circumstances when deciding whether to participate in the Tender Offer.

Qualifying Shareholders may participate in the Tender Offer by tendering either all or a proportion of their registered holdings of Ordinary Shares. Each Qualifying Shareholder will be entitled to tender up to their Basic Entitlement, rounded down to the nearest whole number of Ordinary Shares under the Tender Offer. The Tender Offer will also present tendering Qualifying Shareholders with an opportunity to sell an Individual Excess Tender to the extent that other Shareholders tender less than their Basic Entitlement. Qualifying Shareholders are not obliged to tender any of their Ordinary Shares if they do not wish to do so.

The Tender Offer is subject to, amongst other things, the passing of the Tender Offer Resolution, and is also subject to the conditions set out in the Repurchase Agreement and Part 4of the Circular being fulfilled. There is no guarantee that the Tender Offer will take place. The Tender Offer will not proceed if any of the Conditions are not satisfied or if it is withdrawn in accordance with its terms by the Company at any point prior to the announcement of the results of the Tender Offer. Non-fulfilment of any of the Conditions would mean that the Tender Offer could not be implemented and that the Company would have to bear the abortive costs of making the Tender Offer.

To the extent that any Shareholders have tendered less than their Basic Entitlement under the Tender Offer, Individual Excess Tenders will be accepted in proportion to the Total Excess Tenders so that the total number of Ordinary Shares purchased pursuant to the Tender Offer does not exceed 15,625,000. The process by which Individual Excess Tenders will be scaled back, if necessary, is described further in paragraph 2.17 of Part 4 of the Circular.

As at 28 September 2026 (being the Latest Practicable Date), there were 420,866,313 Ordinary Shares in issue, representing the total voting rights of the Company. Should the maximum number of Ordinary Shares be validly tendered, up to 15,625,000 Ordinary Shares may be purchased under the Tender Offer for a maximum aggregate consideration of approximately £12.5 million, all of which will be cancelled. Following completion of the Tender Offer, therefore, the Issued Ordinary Share Capital of the Company, and accordingly its total voting rights, will be reduced to 405,241,313 Ordinary Shares, assuming the Tender Offer is taken up in full. The Company will confirm the exact number in the Tender Offer results announcement.

The Tender Price for Ordinary Shares tendered by Qualifying Shareholders under the Tender Offer is 80 pence equivalent to a premium of 22.0 per cent to the closing mid-market price of an Ordinary Share on the Latest Practicable Date, being 65.6 pence; and a premium of 26.9per cent. to the volume weighted average price of 63.1 pence per Ordinary Share over the three months prior to the Latest Practicable Date.

The Tender Offer will close at 1.00 p.m. on 20 October 2026 and tenders received after that time will not be accepted (unless the Tender Offer is extended).

Purchase of Ordinary Shares

Successfully tendered Ordinary Shares will be purchased from Qualifying Shareholders by Singer Capital Markets, acting as principal, free of commission and dealing charges. Ordinary Shares not validly tendered will not be purchased by Singer Capital Markets.

Following the purchase of Ordinary Shares from Qualifying Shareholders by Singer Capital Markets, acting as principal, such Ordinary Shares will be repurchased by the Company from Singer Capital Markets, pursuant to the terms of the Repurchase Agreement. All Ordinary Shares repurchased by the Company will be cancelled immediately. Any rights of Shareholders who do not participate in the Tender Offer will be unaffected by the Tender Offer. The Ordinary Shares successfully tendered under the Tender Offer and subsequently acquired by the Company from Singer Capital Markets pursuant to the Repurchase Agreement and cancelled will not rank for any future dividends.

All Shareholders who tender Ordinary Shares will receive the Tender Price, subject, where applicable, to the scaling-down arrangements described below and set out in full in paragraph 2.17 of Part 4 of the Circular.

If more than 15,625,000 Ordinary Shares are validly tendered by Qualifying Shareholders and the Tender Offer is oversubscribed, acceptances of validly tendered Ordinary Shares will be scaled-down to determine the extent to which individual tenders are accepted. Accordingly, where scaling-down applies, beyond a Qualifying Shareholder’s Basic Entitlement there is no guarantee that all of the Ordinary Shares which are tendered by Qualifying Shareholders will be accepted for purchase.

If implemented, the Tender Offer could result in existing Shareholders with significant holdings of Ordinary Shares that do not participate in the Tender Offer having their proportionate holding in the Company increased. Shareholders with a significant holding of Ordinary Shares should have regard to their obligations under Rule 9 of the Takeover Code. Having regard to the maximum number of Ordinary Shares that may be acquired and cancelled by the Company under the Tender Offer and the Repurchase Agreement and having regard to the interest in Ordinary Shares disclosed to the Company as at the Latest Practicable Date, the Board does not believe the provisions of Rule 9 will be triggered if Shareholders with existing material holdings in the Company do not participate in the Tender Offer (assuming they maintain their level of shareholding as at the Latest Practicable Date). Shareholders who acquire further Ordinary Shares could potentially trigger obligations under Rule 9 and should therefore, before making such an acquisition, be aware of the potential maximum increase in their proportionate holding as a result of such an acquisition following the completion of the Tender Offer.

Circumstances in which the Tender Offer may not proceed

There is no guarantee that the Tender Offer will take place. The Tender Offer is conditional on, among other things, the passing of the Tender Offer Resolution as set out in the Notice of General Meeting and on satisfaction of the other conditions specified in Part 4 of the Circular.

The Tender Offer is also conditional on there not arising any material adverse change or certain other force majeure events prior to the closing of the Tender Offer. Further details of these conditions are set out in paragraph 2 of Part 4 of the Circular.

The Company has reserved the right at any time prior to the announcement of the results of the Tender Offer, with the prior consent of Singer Capital Markets, to extend the period during which the Tender Offer is open and/or vary the aggregate value of the Tender Offer, based on market conditions and/or other factors, subject to compliance with applicable legal and regulatory requirements. The Company has also reserved the right, in certain circumstances, to require Singer Capital Markets not to proceed with the Tender Offer. Any such decision will be announced by the Company through a Regulatory Information Service.

Full terms and conditions of the Tender Offer

Full details of the Tender Offer, including the terms and conditions on which it is made, are set out in Part 4 of the Circular. Some questions and answers related to the Tender Offer are set out in Part 6 of the Circular.

1. Ongoing authority to buy back Ordinary Shares and Result of Tender Offer

As set out in the expected timetable in Part 1 of the Circular, it is expected that the result of the Tender Offer will be announced on 22 October 2026, at which time the Tender Offer is expected to become unconditional subject to the Tender Conditions described in paragraph 2 of Part 4of the Circular having been satisfied. Until such time as the Tender Offer becomes unconditional, the Tender Offer will be subject to the Tender Conditions described in paragraph 2 of Part 4 of the Circular. Settlement is then expected to take place as set out in the timetable in Part 1 of the Circular and as provided for in Part 4 of the Circular.

Should the number of Ordinary Shares validly tendered under the Tender Offer be significantly less than the maximum permitted under the terms of the Tender Offer, or where the Company decides not to proceed with the Tender Offer, and subject to circumstances prevailing following completion of the Tender Offer, the Board may consider alternative options to return surplus cash to Shareholders including by means of market purchases through the London Stock Exchange, or the distribution of dividends.

1. General Meeting to approve the Tender Offer Resolution

In order to comply with applicable company law, the Tender Offer requires the approval of Shareholders at a general meeting of the Company (“General Meeting”). The Company is convening a General Meeting at 11.00 a.m. on 21 October 2026 to consider and, if thought fit, pass the Tender Offer Resolution to authorise and to approve the terms under which the Tender Offer will be effected.

The Board believes that it is in Shareholders' best interests to conduct this General Meeting, and if approved, confirm the results of the Tender Offer as soon as possible. The Tender Offer Resolution is being proposed as a special resolution and must be passed by at least 75 per cent. of the votes cast (whether in person or by proxy) at the General Meeting. Accordingly, a Notice of General Meeting is set out in Part 8 of the Circular convening the General Meeting to be held at 11.00 a.m. on 21 October 2026. The Company will not purchase Ordinary Shares pursuant to the Tender Offer unless the Tender Offer Resolution is duly passed.

The Tender Offer Resolution seeks authority to make market purchases of Ordinary Shares in connection with the Tender Offer. The Tender Offer Resolution specifies the maximum number of Ordinary Shares which may be acquired, and the fixed price at which Ordinary Shares may be acquired, pursuant to this authority. The authority sought will expire at the conclusion of the Company's annual general meeting held in 2027.

Shareholders will find enclosed with the Circular a Form of Proxy for use in connection with the General Meeting. Whether or not you intend to tender any of your Ordinary Shares under the Tender Offer you are requested to complete and return the Form of Proxy as soon as possible and, in any event, so as to be received by Equiniti, Highdown House, Yeoman Way, Worthing, West Sussex, BN99 6DA no later than 11.00 a.m. on 19 October 2026.

To appoint more than one proxy, additional Forms of Proxy may be obtained by contacting the NIOX Group plc Shareholder Helpline on +44 (0) 371 384 2050 between 8.30 a.m. and 5.30 p.m. (London time) from Monday to Friday (excluding public holidays in England and Wales) or you may photocopy the form. Please indicate in the box next to the proxy holder’s name the number of shares in relation to which they are authorised to act as your proxy. Please also indicate by ticking the box provided if the proxy instruction is one of multiple instructions being given. All forms must be signed and should be returned together in the same envelope.

Alternatively, you may appoint a proxy or proxies electronically by using the CREST electronic voting service or if you are an institutional investor via the ‘Proxymity’ platform in accordance with the procedures set out in Part 8 of the Circular.

The completion and return of a Form of Proxy will not preclude Shareholders from attending the General Meeting and voting in person should they wish to do so. The Notice of General Meeting is set out in Part 8 of the Circular.

1. Tax

Shareholders should be aware that there will be tax considerations that they should take into account when deciding whether or not to participate in the Tender Offer. Summary details of certain UK taxation considerations are set out in Part 5 of the Circular.

Qualifying Shareholders who are in any doubt as to their tax position or who are subject to tax in a jurisdiction other than the UK are strongly recommended to consult an appropriate professional adviser before tendering their Ordinary Shares under the Tender Offer.

1. Overseas Shareholders

The attention of Shareholders who are not resident in the United Kingdom is drawn to paragraph 6 of Part 4 of the Circular.

It is the responsibility of all Overseas Shareholders to satisfy themselves as to the observance of any legal requirements in their jurisdiction, including, without limitation, any relevant requirements in relation to the ability of such holders to complete and return a Tender Form. If you are in any doubt about your position, you should consult your professional adviser in the relevant jurisdiction.

1. Repurchase Agreement

The Tender Offer is to be effected by Singer Capital Markets (acting as principal) purchasing Ordinary Shares from Shareholders, such purchases to be market purchases in accordance with the provisions of the AIM Rules for Companies and the rules of the London Stock Exchange.

Immediately following completion of the Tender Offer and if the put option or call option under the Repurchase Agreement is exercised, Singer Capital Markets shall sell such Ordinary Shares to the Company, at a price per Ordinary Share equal to the Tender Price, pursuant to the Repurchase Agreement, details of which are set out in paragraph 7 of Part 7 of the Circular.

On 29 September 2026, the Company entered into the Repurchase Agreement with Singer Capital Markets. Pursuant to the terms of the Repurchase Agreement, and conditional on the Tender Offer becoming unconditional in all respects and not lapsing or terminating in accordance with its terms and to Singer Capital Markets being registered as the holder of the Ordinary Shares purchased by Singer Capital Markets pursuant to the Tender Offer, the Company has granted a put option to Singer Capital Markets which, on exercise, obliges the Company to purchase from Singer Capital Markets at the Tender Price, the Ordinary Shares purchased by Singer Capital Markets pursuant to the Tender Offer. Also, under the Repurchase Agreement, Singer Capital Markets has granted the Company a call option which, on exercise, obliges Singer Capital Markets to sell to the Company, at the Tender Price, the Ordinary Shares purchased by Singer Capital Markets pursuant to the Tender Offer.

If the put option or call option under the Repurchase Agreement is exercised, all successfully tendered Ordinary Shares will, once acquired by the Company from Singer Capital Markets pursuant to the Repurchase Agreement following the closing of the Tender Offer, be cancelled.

1. Intentions of the Directors relating to the Tender Offer

Each Director who holds Ordinary Shares intends to:

1. vote in favour of the Tender Offer Resolution; and
2. tender their respective Basic Entitlements under the Tender Offer, being 357,043 Ordinary Shares in aggregate and representing approximately 0.1 per cent. of the Issued Ordinary Share Capital as at the date of the Circular.

The effect of the Tender Offer on the interests of the Directors does not differ from the effect on the interests of other Shareholders.

1. Actions to be taken

Before the General Meeting

Whether or not you intend to tender any of your Ordinary Shares under the Tender Offer or attend the General Meeting in person, you are requested to complete and return the Form of Proxy in accordance with the instructions printed thereon. Please complete the proxy form enclosed with the Circular and return it to Equiniti, Highdown House, Yeoman Way, Worthing, West Sussex, BN99 6DA as soon as possible and, in any event, so as to be received by no later than 11.00 a.m. on 19 October 2026.

To appoint more than one proxy, additional Forms of Proxy may be obtained by contacting the NIOX Group plc Shareholder Helpline on +44 (0) 371 384 2050 between 8.30 a.m. and 5.30 p.m. (London time) from Monday to Friday (excluding public holidays in England and Wales) or you may photocopy the form. Please indicate in the box next to the proxy holder’s name the number of shares in relation to which they are authorised to act as your proxy. Please also indicate by ticking the box provided if the proxy instruction is one of multiple instructions being given. All forms must be signed and should be returned together in the same envelope.

Alternatively, you may appoint a proxy or proxies electronically by using the CREST electronic voting service or if you are an institutional investor via the ‘Proxymity’ platform in accordance with the procedures set out in Part 8 of the Circular.

If you wish to participate in the Tender Offer

If you hold your Ordinary Shares in certificated form and you wish to tender some or all of your Ordinary Shares, you should complete the Tender Form in accordance with the instructions printed on it and in Part 4 of the Circular and return it by post in the accompanying reply-paid envelope (for use in the UK only) to Equiniti, Corporate Actions, Highdown House, Yeoman Way, Worthing, West Sussex, BN99 6DA, together with your share certificate(s) in respect of the Ordinary Shares tendered. Tender Forms and share certificate(s) and/or other document(s) of title must be received by the Receiving Agent as soon as possible but in any event by no later than 1.00 p.m. on 20 October 2026.

If you hold your Ordinary Shares in uncertificated form and you wish to tender some or all of your Ordinary Shares, you should send a TTE Instruction and follow the procedures set out in Part 4 of the Circular in respect of tendering uncertificated Ordinary Shares.

Qualifying Shareholders who do not wish to sell any Shares under the Tender Offer do not need to take any action, either in relation to the Tender Form or the sending of a TTE Instruction.

Shareholders are reminded that the Tender Offer is not being made to certain Overseas Shareholders.

If you have any questions about the procedure for tendering Ordinary Shares or making a TTE Instruction, you require extra copies of the Circular or the Tender Form or you want help filling in the Tender Form, please telephone the Shareholder Helpline on +44 (0) 371 384 2050. Lines are open from 8.30 a.m. to 5.30 p.m. (London time) Monday to Friday (except public holidays in England and Wales). Please note that calls to these numbers may be monitored or recorded for security and training purposes.

Please note that for legal reasons, the Shareholder Helpline will only be able to provide information contained in the Circular and the accompanying Tender Form and will be unable to give advice on the merits of the Tender Offer or to provide financial, investment or taxation advice.

You are advised to read all of the information contained in the Circular before deciding on the course of action you will take in respect of the General Meeting and the Tender Offer.

The results of the General Meeting will be announced through a Regulatory Information Service and the Company's website as soon as possible once known. It is expected that this will be on 21 October 2026.

Notification of interests

Under the DTRs, certain Shareholders are required to notify the Company of their interests in Ordinary Shares. Following the Company’s purchase of Ordinary Shares from Singer Capital Markets pursuant to the terms of the Repurchase Agreement, and regardless of whether a Shareholder tenders any or all of their Ordinary Shares pursuant to the terms of the Tender Offer, the number of Ordinary Shares in which a Shareholder is interested when taken as a percentage of the Company’s aggregate issued Ordinary Share capital as a whole may change, which may give rise to an obligation under the DTRs on the part of such Shareholder to notify the Company of their interest in Ordinary Shares within two trading days of becoming aware of such change. If you are in doubt as to whether you should notify the Company, or as to the form of that notification, please consult your professional adviser.

1. Recommendations

The Board considers that the Tender Offer is in the best interests of Shareholders as a whole. Accordingly, the Board recommends that Shareholders vote in favour of the Tender Offer Resolution, as they intend to do in respect of their own holdings of Ordinary Shares representing, in aggregate, approximately 2.3 per cent. of the Issued Share Capital of the Company as at the Latest Practicable Date.

The Board is making no recommendation to individual Shareholders in relation to participation in the Tender Offer. Whether or not Shareholders decide to tender their Ordinary Shares will depend, amongst other things, on their own individual circumstances, including their own tax position. Shareholders are recommended to consult an appropriately authorised independent adviser in determining whether or not to participate in the Tender Offer and to the extent of such participation.

Should the Tender Offer Resolution not be approved by the requisite majority of the Shareholders at the General Meeting, the Tender Offer will not occur.

IMPORTANT NOTICES

Forward looking statements

This Announcement contains indications of likely future developments and other forward-looking statements that are subject to risk factors associated with, among other things, the economic and business circumstances occurring from time to time in the countries, sector and business segments in which the Group operates. These factors include, but are not limited to, those discussed in Part 3 of the Circular. These and other factors could adversely affect the Company's and/or Group's results, strategy and prospects. Forward-looking statements involve risks, uncertainties and assumptions. They relate to events and/or depend on circumstances in the future which could cause actual results and outcomes to differ materially from those currently anticipated. No obligation or duty is assumed (except as required by the AIM Rules, the DTRs, the rules of the London Stock Exchange and by law) to update any forward-looking statements, whether as a result of new information, future events or otherwise.

No person has been authorised to give any information or make any representations other than those contained in this Announcement and, if given or made, such information or representations must not be relied on as having been so authorised. The release of this Announcement shall not, under any circumstances, create any implication that there has been no change in the affairs of the Company since the date of the Announcement or that the information in it is correct as of any subsequent time. The contents of the website of the Company, and any website directly or indirectly linked to that website, do not form part of this Announcementand should not be relied upon.

Overseas shareholders

The availability of the Tender Offer to Shareholders who are not resident in the United Kingdom may be affected by the laws of the relevant jurisdiction in which they are located. Persons who are not resident in the United Kingdom should read the paragraph headed "Overseas Shareholders" set out in paragraph 6 of Part 4 of the Circular and should inform themselves about, and observe, any applicable legal or regulatory requirements.

Further Information

Any decision to participate in the Tender Offer should only be made on the basis of an independent review by a Qualifying Shareholder of the Company's publicly available information. Whether or not Shareholders decide to tender their Ordinary Shares will depend, amongst other things, on their own individual circumstances, including their own tax position. Shareholders are recommended to consult their duly authorised independent advisers in making their own decisions. Attention is drawn in particular to the risk factors set out in the Circular to be sent to Shareholders later today.

The Tender Offer will be made solely through the Circular and the accompanying Form of Proxy and Tender Form, which contain the full terms and conditions of the Tender Offer, including details of how to vote in respect of the Tender Offer Resolution. Any approval, decision or other response to the Tender Offer should be made only on the basis of the information in the Circular. Qualifying Shareholders are strongly advised to read the formal documentation in relation to the Tender Offer.

The statements contained in this Announcement are made as at the date of this Announcement, unless some other time is specified in relation to them, and release of this Announcement shall not give rise to any implication that there has been no change in the facts set forth in this Announcement since such date. The statements in this Announcement are not to be construed as legal, business, financial or tax advice.

General

Singer Capital Markets Securities Limited ("Singer Capital Markets"), which is authorised and regulated by the Financial Conduct Authority, is acting exclusively for the Company and no-one else as financial adviser and broker in connection with the Tender Offer and Singer Capital Markets, its affiliates and its and their respective directors, officers, employees and agents will not regard any other person as their client, nor will they be responsible to any person other than the Company for providing the protections afforded to their clients, or for providing advice in relation to the Tender Offer or any other matters or arrangements referred to or contained in this Announcement.

Apart from the responsibilities and liabilities, if any, which may be imposed on Singer Capital Markets by FSMA or the regulatory regime established thereunder, Singer Capital Markets does not accept any responsibility or liability whatsoever nor make any representation or warranty, express or implied, concerning the contents of this Announcement, including its accuracy, completeness or verification, or for any other statement made or purported to be made by it, or on its behalf, in connection with the Tender Offer, this Announcement or the Circular. Each of Singer Capital Markets, its affiliates and their respective directors, officers, employees and agents accordingly disclaims all and any responsibility or liability whether arising in tort, contract or otherwise (save as referred to above) which it might otherwise have in respect of this Announcement or any such statement.

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