Pennon Regulatory News (PNN)

PENNON GROUP PLC

FOR IMMEDIATE RELEASE

HOLDING IN COMPANY

NOTIFICATION OF MAJOR INTERESTS IN SHARES

1. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached:

PENNON GROUP PLC / GB00B18V8630

2. Reason for the notification

Acquisition of voting rights.

3. Full name of person(s) subject to the notification obligation

Royal London Asset Management Limited

4. Full name of shareholder(s)

Registered Shareholder:

HSBC Global Custody Nominees (UK) Ltd 12,453,831

3.0207%

5. Date of the transaction and date on which the threshold is crossed or reached:

16 December 2015

6. Date on which issuer notified:

17 December 2015

7. Threshold(s) that is crossed: above 3%

8. Notified details:

A: Voting rights attached to shares

Resulting situation after the triggering transaction

B: Financial Instruments

Resulting situation after the triggering transaction

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments Resulting situation after the triggering transaction

Total (A+B+C)

9. Chain of controlled undertakings through which the voting rights and/or the financial instruments are effectively held, if applicable:

See 4 above

Proxy Voting:

10. Name of the proxy holder:

N/A

11. Number of voting rights proxy holder will cease to hold:

N/A

12. Date on which proxy holder will cease to hold voting rights:

N/A

13. Additional information:

-

A: Identity of the person or legal entity subject to the notification obligation

14. Contact Name: Mamoon Hussain

15. Contact telephone number: 0207 506 6662

B: Identity of the notifier

Full name (including legal form for legal entities):

Pennon Group Plc

Contact address (registered office for legal entities):

Peninsula House, Rydon Lane, Exeter, Devon, EX2 7HR

Contact name Richard Zmuda - Assistant Company Secretary

Phone number 01392 443517

17 December 2015

www.pennon-group.co.uk