Henderson Group - Holding(s) in Company: Lansdowne

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

Henderson Group plc

Sedol B3CM952

2. Reason for the notification  (please tick the appropriate box or boxes)

An acquisition or disposal of voting rights

X

An acquisition or disposal of financial instruments which may result in the acquisition of shares already issued to which voting rights are attached

An event changing the breakdown of voting rights

Other (please specify): Initial Notification of shareholding under Transparency Directive

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

Lansdowne Partners Limited being the General Partner of Lansdowne Partners Limited Partnership (1)

Lansdowne Partners International Limited (2)

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

HSBC Client Holdings UK Ltd

Vidacos Nominees Ltd

(Registered Shareholders)

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

27/03/2012

6. Date on which issuer notified:

28/03/2012

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 the ISIN CODE

Situation previous to the Triggering transaction

Resulting situation after the triggering transaction

Number of Voting Rights

Number of shares

Number of voting rights

% of voting rights

Direct

Indirect

Direct

Indirect

Ordinary Shares

JE00B3CM9527

45,098,010

45,098,010

Below 5%

Below 5%

B: Financial Instruments

Resulting situation after the triggering transaction

Type of financial instrument

Expiration date

Exercise/ Conversion Period/ Date

Number of voting rights that may be acquired if the instrument is exercised/ converted.

% of voting rights

Total (A+B)

Number of voting rights

% of voting rights

Below 5%

Below 5%

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

Lansdowne Partners International Limited is the parent undertaking of Lansdowne Partners Limted.

Proxy Voting:

10. Name of the proxy holder:

Lansdowne Partners Limted

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:

Based on ordinary shares in issue of 1,103,339,862

14. Contact name:

Kamran Salahuddin

15. Contact telephone number:

+44(0)20 7290 5500