Inmarsat Regulatory News (ISAT)

1. Identity of the issuer or the underlying issuerof existing shares to which voting rights areattached: ii

Inmarsat PLC

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

An acquisition or disposal of voting rights

S

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

¨

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

¨

An event changing the breakdown of voting rights

¨

Other (please specify):

¨

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

BlackRock, Inc.

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

5. Date of the transaction and date onwhich the threshold is crossed orreached: v

12 September, 2016

6. Date on which issuer notified:

13 September, 2016

7. Threshold(s) that is/are crossed orreached: vi, vii

Voting rights attached to shares holding for BlackRock, Inc. has gone below 5%

8. Notified details:

A: Voting rights attached to shares viii, ix

Class/type ofshares

if possible usingthe ISIN CODE

Situation previousto the triggeringtransaction

Resulting situation after the triggering transaction

NumberofShares

NumberofVotingRights

Numberof shares

Number of votingrights

% of voting rights x

Direct

Direct xi

Indirect xii

Direct

Indirect

GB00B09LSH68

36,954,975

36,954,975

N/A

N/A

18,772,960

N/A

4.16%

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Expirationdate xiii

Exercise/Conversion Period xiv

Number of votingrights that may beacquired if theinstrument isexercised/ converted.

% of votingrights

Securities Lending

10,289,152

2.28%

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments xv, xvi

Resulting situation after the triggering transaction

Type of financialinstrument

Exercise price

Expiration date xvii

Exercise/Conversion period xviii

Number of voting rights instrument refers to

% of voting rights xix, xx

CFD

3,159,324

Nominal

Delta

0.70%

0.70%

Total (A+B+C)

Number of voting rights

Percentage of voting rights

32,221,436

7.14%

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

See Annex 1

Proxy Voting:

10. Name of the proxy holder:

11. Number of voting rights proxy holder will ceaseto hold:

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

13. Additional information:

BlackRock Regulatory Threshold Reporting Team

14. Contact name:

Marc-Oliver Lesch

15. Contact telephone number:

020 7743 3650

Annex 1

Name

% of voting rights if it equals or is higher than the notifiable threshold

% of voting rights through financial instruments if it equals or is higher than the notifiable threshold

Total of both if it equals or is higher than the notifiable threshold

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock Holdco 4, LLC

BlackRock Holdco 6, LLC

BlackRock Delaware Holdings Inc.

BlackRock Fund Advisors

BlackRock Institutional Trust Company, National Association

BlackRock, Inc.

Trident Merger, LLC

BlackRock Investment Management, LLC

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock International Holdings, Inc.

BR Jersey International Holdings L.P.

BlackRock Group Limited

BlackRock Investment Management (UK) Limited

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock International Holdings, Inc.

BR Jersey International Holdings L.P.

BlackRock Australia Holdco Pty. Ltd.

BlackRock Investment Management (Australia) Limited

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock Capital Holdings, Inc.

BlackRock Advisors, LLC

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock International Holdings, Inc.

BR Jersey International Holdings L.P.

BlackRock (Singapore) Holdco Pte. Ltd.

BlackRock Asia-Pac Holdco, LLC

BlackRock HK Holdco Limited

BlackRock Cayco Limited

BlackRock Trident Holding Company Limited

BlackRock Japan Holdings GK

BlackRock Japan Co., Ltd.

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock International Holdings, Inc.

BR Jersey International Holdings L.P.

BlackRock Group Limited

BlackRock Advisors (UK) Limited

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock Holdco 4, LLC

BlackRock Holdco 6, LLC

BlackRock Delaware Holdings Inc.

BlackRock Fund Advisors

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock International Holdings, Inc.

BR Jersey International Holdings L.P.

BlackRock (Singapore) Holdco Pte. Ltd.

BlackRock Asia-Pac Holdco, LLC

BlackRock HK Holdco Limited

BlackRock Asset Management North Asia Limited

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock International Holdings, Inc.

BR Jersey International Holdings L.P.

BlackRock Holdco 3, LLC

BlackRock Canada Holdings LP

BlackRock Canada Holdings ULC

BlackRock Asset Management Canada Limited

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock International Holdings, Inc.

BR Jersey International Holdings L.P.

BlackRock Group Limited

BlackRock Investment Management (UK) Limited

BlackRock Asset Management Deutschland AG

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock International Holdings, Inc.

BR Jersey International Holdings L.P.

BlackRock Group Limited

BlackRock International Limited

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock International Holdings, Inc.

BR Jersey International Holdings L.P.

BlackRock Group Limited

BlackRock (Netherlands) B.V.

BlackRock, Inc.

BlackRock Holdco 2, Inc.

BlackRock Financial Management, Inc.

BlackRock International Holdings, Inc.

BR Jersey International Holdings L.P.

BlackRock (Singapore) Holdco Pte. Ltd.

BlackRock (Singapore) Limited