Henderson Group: Holding(s) in Company: Wellington

 TR-1: Notification of Major Interests in Shares

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

Henderson Group plc

2. Reason for the notification  (yes/no)

An acquisition or disposal of voting rights

Yes

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

No

An acquisition or disposal of instruments with similar economic effect to qualifying financial instruments

No

An event changing the breakdown of voting rights

No

Other (please specify): ______________

No

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

Wellington Management Company, LLP

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

BBH ISL Nominees Ltd

Goldman Sachs International

HSBC Global Custody Nominee (UK) Limited

JP Morgan Chase Nominees Limited

Mellon Nominees (UK) Ltd

Nortrust Nominees Limited

ROY Nominees Limited

State Street Nominees Limited

Vidacos Nominees Limited

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

12 August 2014

6. Date on which issuer notified:

13 August 2014

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 use ISIN CODE

Situation previous to the triggering transaction

Resulting situation after the triggering transaction

Number of Shares

Number of voting rights

Number of shares

Number of voting rights

Percentage of voting rights

Direct

Indirect

Direct

Indirect

JE00B3CM95277 Ordinary Shares

AU000000HGG2

CHESS Depository Interests

61,294,888

( 61,056,626 ordinary shares and 238,262 CHESS depository interests or 61,294,888 ordinary shares on a converted basis)

61,294,888

( 61,056,626 ordinary shares and 238,262 CHESS depository interests or 61,294,888 ordinary share votes on a converted basis)

55,342,341

( 55,051,780 ordinary shares and 290,561 CHESS depository interests or 55,342,341 ordinary shares on a converted basis)

55,342,341

( 55,051,780 ordinary shares and 290,561 CHESS depository interests or 55,342,341 ordinary share votes on a converted basis)

4.88%

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financial instrument

Expiration date

Exercise/ conversion period

No. of voting rights that may be acquired (if the instrument is exercised/converted)

Percentage of voting rights

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financial instrument

Exercise Price

Expiration date

Exercise/ conversion period

No. of voting rights instrument refers to

Percentage of voting rights

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

55,342,341 ( 55,051,780 ordinary shares and 290,561 CHESS depository interests or 55,342,341 votes on a converted basis)

4.88%

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

BBH ISL Nominees Ltd - 2,107,014 ordinary shares

Goldman Sachs International - 8,351,905 ordinary shares

HSBC Global Custody Nominee (UK) Limited - 176,907 ordinary shares

JP Morgan Chase Nominees Limited - 5,619,594 ordinary shares

Mellon Nominees (UK) Ltd - 1,253,456 ordinary shares and 290,561 CHESS depository interests

Nortrust Nominees Limited - 2,174,914 ordinary shares

ROY Nominees Limited - 20,760,228 ordinary shares

State Street Nominees Limited - 14,086,595 ordinary shares

Vidacos Nominees Limited - 521,167 ordinary shares

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:

14. Contact name:

John D. Norberg

15. Contact telephone number:

617-790-7265