Holding(s) in Company

Pennon Group PLC
20 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

An acquisition or disposal of voting rights

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

   AXA S.A., 25 Avenue Matignon, 75008 Paris and its group of companies

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)

2 March 2007

6. Date on which issuer notified:

16 March 2007

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



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

B18V863



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                                                            
B18V863                       17,509,291              17,509,291    1,099,362            4.92        0.31               
        


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.



Total (A+B)
Number of voting rights        % of voting rights

18,608,653                     5.23%



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


Name of the Company/Fund                          Number of Shares          % of issued share capital


Sun Life Unit Assurance Ltd A/c X                    5,488,326                       1.54117
                            Direct

Sun Life Unit Assurance Ltd A/c X                    7,371,003                       2.06984
                            Direct
AXA UK Investment Co ICVC                              28,881                        0.00811
Extra Income Fund
                            Indirect

AXA UK Investment Co ICVC                            1,010,573                       0.28378
UK Equity Income Fund
                            Indirect

AXA UK Investment Co ICVC                              20,000                        0.00562
UK Growth Fund
                            Indirect

Sun Life Pensions Management Ltd                       56,313                        0.01581
                            Direct

Sun Life Pensions Management Ltd A/c                 3,260,439                       0.91556
                            Direct

AXA Insurance UK                                      171,320                        0.04811
                            Direct

AXA UK Group Pension Scheme                            23,000                        0.00646
                            Indirect

Sun Life International (IOM) Ltd                      100,000                        0.02808
                            Direct

Sun Life Pensions Management Ltd                       11,758                        0.00330
                            Direct

Sun Life Pensions Management Ltd                       2,500                         0.00070
                            Direct

Sun Life Unit Assurance Ltd                            87,608                        0.02460
LTAV UK Equity
                            Direct

Sun Life Unit Assurance Ltd                            64,327                        0.01806
FTSE All Share Tracker
                            Direct

Sun Life Pensions Management                          393,782                        0.11058
LTAV UK Equity
                            Direct

Sun Life Pensions Management                          296,254                        0.08319
FTSE All Share Tracker
                            Direct

Framlington onshore private clients                    16,908                        0.00475
                            Indirect

AXA Winterthur                                        205,661                        0.05775
                            Direct

                            Total Direct             17,509,291                      4.91675

                            Total Indirect           1,099,362                       0.30871
                            TOTAL                    18,608,653                      5.22546



Proxy Voting:



10. Name of the proxy holder:





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





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





13. Additional information:



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





20 March 2007



www.pennon-group.co.uk



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