Holding(s) in Company

Rosslyn Data Technologies plc

(the "Company", "Rosslyn" or the "Group")

Holdings in Company

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARESi

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

Rosslyn Data Technologies Plc

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

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

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

An event changing the breakdown of voting rights

Yes

Other (please specify):

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

Kestrel Partners LLP

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

Kestrel Opportunities, a cell of Guernsey Portfolios PCC Ltd (through BNY Mellon Nominees Limited) and various other clients of Kestrel Partners LLP (through Bank of New York Nominees Ltd)

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

15 May 2017

6. Date on which issuer notified:

15 May 2017

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

through 12%

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

Ordinary Shares of 0.5p each

ISIN GB00BKX5CP01

0

0

n/a

n/a

23,150,000

n/a

12.31%

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

n/a

n/a

n/a

n/a

n/a

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

n/a

n/a

n/a

n/a

n/a

Nominal

Delta

n/a

n/a

Total (A+B+C)

Number of voting rights

Percentage of voting rights

23,150,000

12.31%

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

Indirect - BNY Mellon Nominees Limited - 19,677,500 Shares. 10.46% of voting rights

Indirect - Bank of New York Nominees Limited - 3,472,500 Shares. 1.85% of voting rights

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:

Disclosure based on Total voting rights of 188,130,067

The indirect voting rights held under (9) relate to shares held in client portfolios managed by Kestrel Partners LLP under discretionary investment management agreements

14. Contact name:

Ian Forrest

15. Contact telephone number:

0203 371 6100