INVESTOR RELATIONS

TR-1(i): NOTIFICATION OF MAJOR INTERESTS IN SHARES

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

STM Group PLC

2. Reason for the notification (please state Yes/No): ( )

An acquisition or disposal of voting rights: ( )

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: (X)

Other (please specify): ( )

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

Paul Chase-Gardener

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

Barclays Stockbrokers Ltd
Rock Nominees Ltd
STM Fidecs Nominees Ltd

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

12/02/2013

6. Date on which issuer notified:

14/03/2013

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

Under 3%

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
	Number of shares	Number of voting Rights
IM00B1S9KY98 Ord 0.1p	5,420,640	5,420,640

Resulting situation after the triggering transaction (vii)

Class/type of shares if possible using the ISIN CODE	Number of shares	Number of voting rights		% of voting rights
	Direct	Direct	Indirect	Direct	Indirect

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

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

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	Number of voting rights instrument refers to	% of voting rights
					Nominal	Delta
n/a	n/a	n/a	n/a	n/a	n/a	n/a

Total (A+B+C)

Number of voting rights	% of voting rights
Under 3%	Under 3%

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

Under 3%

Proxy Voting:

10. Name of the proxy holder:

n/a

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

n/a

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

n/a

13. Additional information:

Paul Chase-Gardener is no longer a shareholder in Rock Holdings Ltd, has resigned from all directorships of Rock Holdings group companies, therefore, is no longer interested in the share capital of any Rock Holdings group companies. Subsequently his shares held in STM Group PLC now fall under 3%

14. Contact name:

Andrea Falcon

15. Contact number:

+44 (0) 1454 634 853