Result Of Rump Placing

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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

RESULT OF RUMP PLACING

Following the announcement earlier today regarding valid acceptances under the fully underwritten Rights Issue of Pennon Group plc (the “Company”) announced on 7 October 2026, the Company confirms Barclays Bank PLC and Morgan Stanley & Co. International plc, as underwriters in respect of the Rights Issue (together, the “Underwriters”), have successfully procured subscribers for all of the New Ordinary Shares for which valid acceptances were not received, representing approximately 5.8 per cent. of the total number of New Ordinary Shares to be issued pursuant to the Rights Issue, and for all of the New Ordinary Shares resulting from the aggregation of fractional entitlements of New Ordinary Shares, at a price of 330 pence per New Ordinary Share.

Today's placing has been multiple times over-subscribed reflecting continued investor support for the Company. The overall equity raise will be used to fund the increased investment in the regulated water businesses, including the cost change reopener programme, and to maintain gearing within the Company’s long-term policy range throughout AMP8.

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