Holding(s) in Company

Pennon Group PLC
11 April 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)


3 April 2007


6. Date on which issuer notified:


10 April 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 using     Situation previous to the Triggering
the ISIN CODE                                          transaction
                                          Number of       Number of voting
                                          shares          Rights
Ordinary
B18V863                                      19,550,573             19,550,573


Resulting situation after the triggering transaction

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

                       Direct        Direct (x)    Indirect     Direct  Indirect
                                                   (xi)
Ordinary
B18V863                 18,077,802    18,077,802    1,852,771    5.08     0.52




B: Financial Instruments

Resulting situation after the triggering transaction (xii)

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





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

19,930,573                                   5.60%


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      % of issued share
                                               Shares            capital

AXA Sun Life pc                                 380,000                0.10670
(fmly Axa Equity & Law Life Assurance
Society plc)
Direct

Sun Life Unit Assurance Ltd A/c
X                                             5,488,326                1.54113
Direct

Sun Life Unit Assurance Ltd A/c
X                                             7,371,003                2.06979
Direct

AXA UK Investment Co ICVC                        52,079                0.01462
Extra Income Fund
Indirect

AXA UK Investment Co ICVC                     1,740,784                0.48881
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                0.91554
Direct

Sun Life Assurance Society Pc                   190,000                0.05335
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                                              13,158                0.00369
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                      63,608                0.01786
FTSE All Share Tracker
Direct

Sun Life Pensions Management                    393,782                0.11057
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                                  203,491                0.05714
Direct

Total Direct                                 18,077,802                5.07627

Total Indirect                                1,852,771                0.52026

                                   TOTAL     19,930,573                5.59653

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 Christopher Paul Richards - Interim Assistant Company Secretary


Phone number 01392 443060




11 April 2007


www.pennon-group.co.uk


End transmission


                      This information is provided by RNS
            The company news service from the London Stock Exchange