Holding(s) in Company

Pennon Group PLC
21 March 2007


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



2. Reason for the notification

Disclosure triggered by the implementation of the Transparency Directive with
new 5% disclosure threshold



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



            Pictet Asset Management SA



4. Full name of shareholder(s) (if different from 3)





5. Date of the transaction (and date on which the threshold is crossed or
reached if different)



 N/A



6. Date on which issuer notified:



20 March 2007



7. Threshold(s) that is/are crossed or reached:



5%



8. Notified details:





A: Voting rights attached to shares


Class/type of shares if possible              Situation previous to the Triggering transaction
using the ISIN CODE
                                  Number of shares                   Number of voting Rights
Ordinary shares
                                  N/A
GB0009877944                                                         N/A



Resulting situation after the triggering transaction


Class/type of shares if      Number of shares         Number of voting rights (ix)      % of voting rights
possible using the ISIN CODE
                             Direct                   Direct (x)   Indirect (xi)        Direct      Indirect

Ordinary shares                                                         25,599,217       0           7.189
                                 0
GB0009877944                                              0





B: Financial Instruments

Resulting situation after the triggering transaction (xii)


Type of         Expiration Date       Exercise/Conversion       Number of voting rights     % of voting rights
financial       (xiii)                Period/ Date (xiv)        that may be acquired if the
instrument                                                      instrument is exercised/
                                                                converted.

N/A             N/A                   N/A                       N/A                         N/A



Total (A+B)


Number of voting rights        % of voting rights


25,599,217                     7.189



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



      Not applicable.  No controlled undertaking individually holds 3% or more
of the voting rights.



Proxy Voting:



10. Name of the proxy holder:



            Pictet Asset Management SA



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



            25,599,217



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



            Omission



13. Additional information:



            Omission



Annex to Notification Of Major Interests In Shares



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



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   Margaret Lilian Heeley - Assistant Company Secretary



Phone number 01392 443060



21 March 2007



www.pennon-group.co.uk



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