Holding(s) in Company

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARES

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

ARK THERAPEUTICS GROUP PLC

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

An acquisition or disposal of voting rights

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):

Passive Crossing

 x

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

 Smith & Williamson Holdings Limited

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

 See section 9

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

21 February 2012

6. Date on which issuer notified:

23 February 2012

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

12%

8. Notified details:

A: Voting rights attached to shares

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

Direct

Direct

Indirect

Direct

Indirect

Ordinary

GB0034251727

25,292,100

25,292,100

25,092,100

11.98%

B: Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Exerciseprice

Expirationdate

Exercise/Conversionperiod

Number of votingrights instrumentrefers to

% of voting rights

 N/A

Nominal

Delta

Total (A+B)

Number of voting rights

Percentage of voting rights

25,092,100

11.98%

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

Smith and Williamson Nominees Limited, a subsidiary of Smith and Williamson Investment Management Limited, a subsidiary of Smith and Williamson Holdings Limited - 6,417,100 shares

Royal Bank of Scotland as custodian for Smith & Williamson Fund Administration Ltd, a subsidiary of Smith & Williamson Investment Management Limited, a subsidiary of Smith & Williamson Investment Management Limited, a subsidiary of Smith & Williamson Holdings Limited - 4,000,000 shares

BNP Paribas as custodian for Smith and Williamson Investment Management Limited, a subsidiary of Smith & Williamson Holdings Limited - 675,000 shares

BNP Paribas Securities Services as custodian for Smith & Williamson Investment Management (Ireland) Limited, a subsidiary of Smith & Williamson Holdings Limited - 14,000,000 shares

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:

14. Contact name:

Not advised

15. Contact telephone number:

Not advised