Holding(s) in Company

For filings with the FSA include the annex

For filings with issuer exclude the annex

TR-1: Notifications of Major Interests in Shares

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

ARM Holdings plc

2. Reason for notification (yes/no)

An acquisition or disposal of voting rights

Yes

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

No

An event changing the breakdown of voting rights

No

Other (please specify):______________

N/A

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

Janus Capital Management LLC

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

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

15 December 2010

6. Date on which issuer notified:

16 December 2010

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

8%

8: Notified Details

A: Voting rights attached to shares

Class/type of shares

If possible use ISIN code

Ordinary

ISIN:

GB0000595859

Situation previous to the triggering transaction

Resulting situation after the triggering transaction

Number of shares

120,309,543

Number of voting rights

120,309,543

Number of shares

103,236,321

Number of voting rights

Percentage of voting rights

103,236,321

Direct

Indirect

7.81%

Direct

Indirect

B: Financial Instruments

Resulting situation after the triggering transaction

Type of financial instrument

Expiration date

Exercise/ conversion period/date

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

Percentage of voting rights

Total (A+B)

Number of voting rights

Percentage of voting rights

103,236,321

7.81%

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

Proxy Voting:

10. Name of proxy holder:

Janus Capital Management LLC

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

17,073,222

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

15 December 2010

13. Additional information:

14 Contact name:

Joanne O'Sullivan

15. Contact telephone name:

0044 1223 406122