THIS ANNOUNCEMENT AND THE INFORMATION CONTAINED HEREIN IS RESTRICTED AND NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, IN WHOLE OR IN PART, IN OR INTO THE UNITED STATES OF AMERICA, CANADA, AUSTRALIA, JAPAN, THE REPUBLIC OF SOUTH AFRICA OR ANY OTHER JURISDICTION IN WHICH SUCH RELEASE, PUBLICATION OR DISTRIBUTION WOULD BE UNLAWFUL. PLEASE SEE THE IMPORTANT NOTICE AT THE END OF THIS ANNOUNCEMENT.

THE COMMUNICATION OF THIS ANNOUNCEMENT AND ANY OTHER DOCUMENTS OR MATERIALS RELATING TO THE RETAIL OFFER AS A FINANCIAL PROMOTION IS ONLY BEING MADE TO, AND MAY ONLY BE ACTED UPON BY, THOSE PERSONS IN THE UNITED KINGDOM FALLING WITHIN ARTICLE 43 OF THE FINANCIAL SERVICES AND MARKETS ACT 2000 (FINANCIAL PROMOTION) ORDER 2005, AS AMENDED (WHICH INCLUDES AN EXISTING MEMBER OF APTAMER GROUP PLC). ANY INVESTMENT OR INVESTMENT ACTIVITY TO WHICH THIS ANNOUNCEMENT RELATES IS AVAILABLE ONLY TO SUCH PERSONS AND WILL BE ENGAGED IN ONLY WITH SUCH PERSONS. THIS ANNOUNCEMENT IS FOR INFORMATIONAL PURPOSES ONLY, AND DOES NOT CONSTITUTE OR FORM PART OF ANY OFFER OR INVITATION TO SELL OR ISSUE, OR ANY SOLICITATION OF AN OFFER TO PURCHASE OR SUBSCRIBE FOR, ANY SECURITIES OF APTAMER GROUP PLC.

THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION FOR THE PURPOSES OF THE MARKET ABUSE REGULATION (EU) 596 / 2014 WHICH FORMS PART OF UK LAW BY VIRTUE OF THE EUROPEAN UNION (WITHDRAWAL) ACT 2018 ("UK MAR"). UPON THE PUBLICATION OF THIS ANNOUNCEMENT, THIS INSIDE INFORMATION IS NOW CONSIDERED TO BE IN THE PUBLIC DOMAIN AND SUCH PERSONS SHALL THEREFORE CEASE TO BE IN POSSESSION OF INSIDE INFORMATION.

31 March 2026

Aptamer Group plc

("Aptamer Group", the "Company" or the "Group")

Result of Retail Offer

and

Posting of notice of General Meeting

£4.5 million raised pursuant to the Placing, Subscription and the Retail Offer

Aptamer Group plc (AIM: APTA), the leading developer of next-generation synthetic binders delivering innovation to the life science industry, announces that the Retail Offer announced on 26 March 2026 and which closed at 12.00 pm yesterday, has raised c.£274,000, before expenses.

Accordingly, subject to the passing of certain Resolutions at the forthcoming General Meeting (11.00 am on 13 April 2026), the Retail Offer will result in the issue of a total of 45,665,573 Retail Offer Shares at the Issue Price of 0.6p per share, to raise gross proceeds of approximately £274,000. As a result, the Company has raised a total of approximately £4.5 million pursuant to the Placing, Subscription and the Retail Offer, of which approximately £3.1 million remains conditional on the passing of certain Resolutions at the General Meeting.

Notice of General Meeting and posting of Circular

The Circular and notice of General Meeting are available on the Company's website and were posted to shareholders on 27 March 2006.

Unless otherwise defined, definitions contained in this Announcement have the same meaning as set out in the announcement made by the Company on 25 March 2026.

The person responsible for arranging for the release of this Announcement on behalf of Aptamer Group is Dr Arron Tolley, Chief Executive Officer.   

For further information please contact: 

About Aptamer Group

Aptamer Group is a leading developer of next-generation synthetic binders delivering innovation to the life sciences industry. The Group develops Optimer® binders, advanced molecules that work like antibodies by attaching to specific targets in the body. These binders are used in medicine, diagnostic tests, and research tools, offering benefits like high stability, reliable performance, and lower costs compared to traditional antibodies.

Aptamer operates a fee-for-service business in the US$210 billion market for antibody alternatives, working with all top 10 global pharmaceutical companies. It is also building valuable Optimer® assets with partners, aiming for future licensing revenue.

Founded in 2008, the Group listed on the London Stock Exchange AIM market in December 2021 and is headquartered in York, UK.

To register for news alerts by email go to https://aptamergroup.com/investors/investor-news-email-alerts/

This announcement should be read in its entirety. In particular, the information in the "Important Notices" section of the announcement should be read and understood.

IMPORTANT NOTICES

The content of this announcement, which has been prepared by and is the sole responsibility of the Company.

The Retail Offer is only open to investors in the United Kingdom who fall within Article 43 of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (which includes an existing member of the Company).

This announcement and the information contained herein is not for release, publication or distribution, directly or indirectly, in whole or in part, in or into or from the United States (including its territories and possessions, any state of the United States and the District of Columbia (the "United States" or "US")), Australia, Canada, Japan, the Republic of South Africa, any member state of the EEA or any other jurisdiction where to do so might constitute a violation of the relevant laws or regulations of such jurisdiction.

The Retail Offer Shares have not been and will not be registered under the US Securities Act of 1933, as amended (the "US Securities Act") or under the applicable state securities laws of the United States and may not be offered or sold directly or indirectly in or into the United States. No public offering of the Retail Offer Shares is being made in the United States. The Retail Offer Shares are being offered and sold outside the United States in "offshore transactions", as defined in, and in compliance with, Regulation S under the US Securities Act ("Regulation S") to non-US persons (within the meaning of Regulation S). In addition, the Company has not been, and will not be, registered under the US Investment Company Act of 1940, as amended.

This announcement does not constitute an offer to sell or issue or a solicitation of an offer to buy or subscribe for Retail Offer Shares in the United States, Australia, Canada, New Zealand, Japan, the Republic of South Africa, any member state of the EEA or any other jurisdiction in which such offer or solicitation is or may be unlawful. No public offer of the securities referred to herein is being made in any such jurisdiction.

This announcement is not for publication or distribution, directly or indirectly, in or into the United States of America.  This announcement is not an offer of securities for sale into the United States.  The securities referred to herein have not been and will not be registered under the US Securities Act and may not be offered or sold in the United States, except pursuant to an applicable exemption from registration.  No public offering of securities is being made in the United States.

The distribution of this announcement may be restricted by law in certain jurisdictions and persons into whose possession any document or other information referred to herein comes should inform themselves about and observe any such restriction. Any failure to comply with these restrictions may constitute a violation of the securities laws of any such jurisdiction.

Each of Turner Pope ("Broker") and SPARK Advisory Partners Limited ("SPARK" or "Nominated Adviser") (together, the "Banks") is authorised and regulated in the United Kingdom by the Financial Conduct Authority, is acting exclusively for the Company and for no-one else and will not regard any other person (whether or not a recipient of this announcement) as its client in relation to the Retail Offer and will not be responsible to anyone other than the Company for providing the protections afforded to its clients, nor for providing advice in connection with the Retail Offer, Admission and the other arrangements referred to in this announcement.

The value of Ordinary Shares and the income from them is not guaranteed and can fall as well as rise due to stock market movements. When you sell your investment, you may get back less than you originally invested. Figures refer to past performance and past performance is not a reliable indicator of future results. Returns may increase or decrease as a result of currency fluctuations.

Certain statements in this announcement are forward-looking statements which are based on the Company's expectations, intentions and projections regarding its future performance, anticipated events or trends and other matters that are not historical facts. These forward-looking statements, which may use words such as "aim", "anticipate", "believe", "intend", "estimate", "expect" and words of similar meaning, include all matters that are not historical facts. These forward-looking statements involve risks, assumptions and uncertainties that could cause the actual results of operations, financial condition, liquidity and dividend policy and the development of the industries in which the Company's businesses operate to differ materially from the impression created by the forward-looking statements. These statements are not guarantees of future performance and are subject to known and unknown risks, uncertainties and other factors that could cause actual results to differ materially from those expressed or implied by such forward-looking statements. Given those risks and uncertainties, prospective investors are cautioned not to place undue reliance on forward-looking statements.

These forward-looking statements speak only as at the date of this announcement and cannot be relied upon as a guide to future performance. The Company and Turner Pope and SPARK expressly disclaim any obligation or undertaking to update or revise any forward-looking statements contained herein to reflect actual results or any change in the assumptions, conditions or circumstances on which any such statements are based unless required to do so by the Financial Conduct Authority, the London Stock Exchange or applicable law.

The information in this announcement is for background purposes only and does not purport to be full or complete. None of Turner Pope or SPARK or any of their affiliates, accepts any responsibility or liability whatsoever for, or makes any representation or warranty, express or implied, as to this announcement, including the truth, accuracy or completeness of the information in this announcement (or whether any information has been omitted from the announcement) or any other information relating to the Company or associated companies, whether written, oral or in a visual or electronic form, and howsoever transmitted or made available or for any loss howsoever arising from any use of the announcement or its contents or otherwise arising in connection therewith. The Banks, BookBuild and their affiliates, accordingly, disclaim all and any liability whether arising in tort, contract or otherwise which they might otherwise be found to have in respect of this announcement or its contents or otherwise arising in connection therewith.

Any indication in this announcement of the price at which the Ordinary Share have been bought or sold in the past cannot be relied upon as a guide to future performance. Persons needing advice should consult an independent financial adviser. No statement in this announcement is intended to be a profit forecast and no statement in this announcement should be interpreted to mean that earnings or target dividend per share of the Company for the current or future financial years would necessarily match or exceed the historical published earnings or dividends per share of the Company.

Neither the content of the Company's website (or any other website) nor the content of any website accessible from hyperlinks on the Company's website (or any other website) is incorporated into or forms part of this announcement. The Retail Offer Shares to be issued or sold pursuant to the Retail Offer will not be admitted to trading on any stock exchange other than the AIM Market of the London Stock Exchange plc.

It is further noted that the Retail Offer is only open to, and this announcement is directed solely at, investors in the United Kingdom who fall within Article 43 of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (which includes an existing member of the Company). Accordingly, this announcement does not require the approval of the relevant communication by an authorised person.

SPARK, which is authorised and regulated by the FCA in the United Kingdom, is acting as Nominated Adviser to the Company in connection with the Fundraise. SPARK will not be responsible to any person other than the Company for providing the protections afforded to clients of SPARK or for providing advice to any other person in connection with the Fundraise or any acquisition of shares in the Company. SPARK has not authorised the contents of, or any part of, this announcement, no representation or warranty, express or implied, is made by SPARK in respect of such contents, and no liability whatsoever is accepted by SPARK for the accuracy of any information or opinions contained in this Announcement or for the omission of any material information, save that nothing shall limit the liability of SPARK for its own fraud. SPARK's responsibilities as the Company's nominated adviser under the AIM Rules for Nominated Advisers are owed solely to the London Stock Exchange and are not owed to the Company or to any Director or to any other person.

Turner Pope, which is authorised and regulated by the FCA in the United Kingdom, is acting as sole broker and bookrunner to the Company in connection with the Fundraise. Turner Pope will not be responsible to any person other than the Company for providing the protections afforded to clients of Turner Pope or for providing advice to any other person in connection with the Fundraise or any acquisition of shares in the Company. Turner Pope is not making any representation or warranty, express or implied, as to the contents of this Announcement. Turner Pope has not authorised the contents of, or any part of, this Announcement, and no liability whatsoever is accepted by Turner Pope for the accuracy of any information, or opinions contained in this Announcement or for the omission of any material information, save that nothing shall limit the liability of Turner Pope for its own fraud.

UK Product Governance Requirements

Solely for the purposes of the product governance requirements of Chapter 3 of the FCA Handbook Product Intervention and Product Governance Sourcebook (the "UK MiFIR Product Governance Requirements"), and disclaiming all and any liability, whether arising in tort, contract or otherwise, which any "manufacturer" (for the purposes of the UK MiFIR Product Governance Requirements) may otherwise have with respect thereto, the Retail Offer Shares have been subject to a product approval process, which has determined that the Retail Offer Shares are: (i) compatible with an end target market of retail investors and investors who meet the criteria of professional clients and eligible counterparties, each as defined in paragraphs 3.5 and 3.6 of COBS; and (ii) eligible for distribution through all permitted distribution channels (the "Target Market Assessment"). Notwithstanding the Target Market Assessment, distributors should note that: the price of the Retail Offer Shares may decline and investors could lose all or part of their investment; the Retail Offer Shares offer no guaranteed income and no capital protection; and an investment in the Retail Offer Shares is compatible only with investors who do not need a guaranteed income or capital protection, who (either alone or in conjunction with an appropriate financial or other adviser) are capable of evaluating the merits and risks of such an investment and who have sufficient resources to be able to bear any losses that may result therefrom. The Target Market Assessment is without prejudice to any contractual, legal or regulatory selling restrictions in relation to the Retail Offer.

For the avoidance of doubt, the Target Market Assessment does not constitute: (a) an assessment of suitability or appropriateness for the purposes of Chapters 9A or 10A respectively of COBS; or (b) a recommendation to any investor or group of investors to invest in, or purchase, or take any other action whatsoever with respect to the Retail Offer Shares. Each distributor is responsible for undertaking its own target market assessment in respect of the Retail Offer Shares and determining appropriate distribution channels.

EU Product Governance Requirements

Solely for the purposes of the product governance requirements contained within: (a) EU Directive 2014/65/EU on markets in financial instruments, as amended ("MiFID II"); (b) Articles 9 and 10 of Commission Delegated Directive (EU) 2017/593 supplementing MiFID II; and (c) local implementing measures (together, the "MiFID II Product Governance Requirements"), and disclaiming all and any liability, whether arising in tort, contract or otherwise, which any "manufacturer" (for the purposes of the MiFID II Product Governance Requirements) may otherwise have with respect thereto, the Retail Offer Shares have been subject to a product approval process, which has determined that the Retail Offer Shares are: (i) compatible with an end target market of retail investors and investors who meet the criteria of professional clients and eligible counterparties, each as defined in MiFID II; and (ii) eligible for distribution through all distribution channels as are permitted by MiFID II (the "EU Target Market Assessment"). Notwithstanding the EU Target Market Assessment, distributors should note that: the price of the Retail Offer Shares may decline and investors could lose all or part of their investment; the Retail Offer Shares offer no guaranteed income and no capital protection; and an investment in the Retail Offer Shares is compatible only with investors who do not need a guaranteed income or capital protection, who (either alone or in conjunction with an appropriate financial or other adviser) are capable of evaluating the merits and risks of such an investment and who have sufficient resources to be able to bear any losses that may result therefrom. The EU Target Market Assessment is without prejudice to the requirements of any contractual, legal or regulatory selling restrictions in relation to the Retail Offer.

For the avoidance of doubt, the EU Target Market Assessment does not constitute: (a) an assessment of suitability or appropriateness for the purposes of MiFID II; or (b) a recommendation to any investor or group of investors to invest in, or purchase or take any other action whatsoever with respect to the Retail Offer Shares. Each distributor is responsible for undertaking its own target market assessment in respect of the Retail Offer Shares and determining appropriate distribution channels.