Results Of Rights Issue

NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, DIRECTLY OR INDIRECTLY, IN WHOLE OR IN PART, INTO, WITHIN OR FROM THE UNITED STATES, NEW ZEALAND, CHINA, SINGAPORE, HONG KONG, SOUTH AFRICA, JAPAN, THE UNITED ARAB EMIRATES AND ANY OTHER JURISDICTION WHERE TO DO SO WOULD CONSTITUTE A VIOLATION OF THE RELEVANT LAWS OR REGULATIONS OF SUCH JURISDICTION.

THIS ANNOUNCEMENT DOES NOT CONSTITUTE A PROSPECTUS (OR A PROSPECTUS EQUIVALENT DOCUMENT OR AN EXEMPTED DOCUMENT). NOTHING HEREIN SHALL CONSTITUTE AN OFFERING OF ANY SECURITIES. NOTHING IN THIS ANNOUNCEMENT SHOULD BE INTERPRETED AS A TERM OR CONDITION OF THE RIGHTS ISSUE. ANY DECISION TO PURCHASE, SUBSCRIBE FOR, OTHERWISE ACQUIRE, SELL OR OTHERWISE DISPOSE OF ANY NIL PAID RIGHTS, FULLY PAID RIGHTS OR NEW ORDINARY SHARES MUST BE MADE ONLY ON THE BASIS OF THE INFORMATION CONTAINED IN THE INTERNATIONAL OFFERING CIRCULAR. PLEASE SEE THE IMPORTANT NOTICES AT THE END OF THIS ANNOUNCEMENT.

PENNON GROUP PLC

RESULTS OF RIGHTS ISSUE

Pennon Group plc (the “Company”) announces that the 7 for 15 Rights Issue of 220,257,997 New Ordinary Shares at 250 pence per New Ordinary Share announced on 7 October 2026 has closed for acceptances. The Company received valid acceptances in respect of 207,546,531 New Ordinary Shares, representing approximately 94.229 per cent of the total number of New Ordinary Shares to be issued pursuant to the fully underwritten Rights Issue.

It is expected that the New Ordinary Shares will commence trading, fully paid, on the London Stock Exchange plc’s main market for listed securities at 8:00 a.m. today.

It is expected that the New Ordinary Shares in uncertificated form will be credited to CREST accounts as soon as possible after 8:00 a.m. today, that definitive share certificates in respect of the New Ordinary Shares held in certificated form will be dispatched no later than 10 November 2026, and that the online accounts for Shareholders who hold their New Ordinary Shares through the WaterShare+ Nominee and the Corporate Sponsored Nominee will be credited no later than 10 November 2026.

In accordance with their obligations as underwriters in respect of the Rights Issue as set out in the International Offering Circular dated 7 October 2026, Barclays Bank PLC and Morgan Stanley & Co. International plc (together, the “Underwriters”) will use reasonable endeavours to procure subscribers at the Rights Issue Price for the remaining 12,664,157 New Ordinary Shares not taken up by Qualifying Shareholders, subject to the terms and conditions of the Underwriting Agreement, failing which the Underwriters have agreed to subscribe themselves (in the agreed proportions), on a several basis, for any remaining New Ordinary Shares at the Rights Issue Price.

In addition to the New Ordinary Shares not taken up at the Rights Issue Price, the Underwriters will also place 47,309 New Ordinary Shares resulting from the aggregation of fractional entitlements of New Ordinary Shares following the Rights Issue. Holdings of Existing Ordinary Shares in certificated and uncertificated form, holdings of Existing Ordinary Shares through the Corporate Sponsored Nominee and holdings of Existing Ordinary Shares through the WaterShare+ Nominee are each to be treated as separate holdings for the purpose of calculating entitlements under the Rights Issue.

The net proceeds from the placing of the New Ordinary Shares not taken up (after the deduction of the Rights Issue Price of 250 pence per New Ordinary Share and the expenses of procuring subscribers, including any applicable brokerage fees and commissions and amounts in respect of related irrecoverable VAT) will be paid (without interest) to those persons entitled to lapsed provisional allotments in accordance with the terms of the Rights Issue, pro rata to their lapsed provisional allotments, save that amounts of less than £5.00 per holding will not be paid to such persons but will be aggregated and will accrue for the benefit of the Company, and the Company intends to apply such proceeds towards the Better Futures Fund.

The proceeds from the sale of New Ordinary Shares resulting from the aggregation of fractional entitlements (net of related expenses, including any applicable brokerage fees and commissions and amounts in respect of related irrecoverable VAT) will be paid in due proportion to the relevant Shareholders, save that individual amounts of less than £5.00 will not be paid to such persons but will accrue for the benefit of the Company, and the Company intends to apply such proceeds towards the Better Futures Fund.

Unless the context requires otherwise, capitalised terms used but not otherwise defined in this announcement shall have the meanings set out in the International Offering Circular dated 7 October 2026 (the “IOC”), which is available on the Company’s website at: www.pennon-group.co.uk/investor-information.

NOTICE TO ALL INVESTORS

This announcement and any offer of securities to which it relates are only addressed to and directed at persons who: (i) have professional experience in matters relating to investments who fall within the definition of “investment professionals” in Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the “Order”); (ii) fall within Article 49(2)(a) to (d) of the Order; or (iii) are persons to whom it may otherwise lawfully be communicated.

The Underwriters may, in accordance with applicable legal and regulatory provisions and subject to the terms of the Underwriting Agreement, engage in transactions in relation to the Nil Paid Rights and the Ordinary Shares. Subject to any contractual obligations that may be in place between the Company and the Underwriters, in the event that the Underwriters or their respective affiliates subscribe for New Ordinary Shares which are not taken up by Qualifying Shareholders, the Underwriters and their respective affiliates may for a limited period co-ordinate disposals of such shares in accordance with applicable law and regulation. Except as required by applicable law or regulation, the Underwriters and their respective affiliates do not propose to make any public disclosure in relation to such transactions.

INFORMATION TO DISTRIBUTORS