COGSTATE LTD — Capital/Financing Update 2008

Aug 3, 2008

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4[th] August 2008

CogState Ltd ABN 80 090 975 723 Level 7 21 Victoria Street Melbourne 3000 Telephone +61 3 9664 1300 Facsimile +61 3 9664 1301 www.cogstate.com

Dear Option holder,

CogState Limited – Non-Renounceable Rights Issue

On 29[th] July 2008, CogState Limited (the “Company”) announced a fully underwritten non-renounceable rights issue of approximately 5,967,553 new fully paid ordinary shares (“Rights Issue”) under which its eligible shareholders will be offered one fully paid ordinary share in the Company (“New Share”) for every ten fully paid ordinary shares held on the record date, at an issue price of $0.1027.

The Rights Issue will be fully underwritten by

• United BioSource Corporation

• Myer & Myer Pty Ltd

• DA & DG Simpson

• Wooldridge Colman Superannuation Fund

• Mr. Richard Morgan

• Angeheni Investments Pty Ltd

The underwriters will not be paid any underwriting fee for underwriting the Rights Issue.

The Rights Issue will raise approximately $0.6 million before costs. The funds raised will be used for general working capital allowing CogState to continue expansion in the clinical trial market while also allowing for investment of resources in the potentially lucrative home testing and work place markets.

Under the terms and conditions of the options that you currently hold there is no entitlement to participate in the Rights Issue. In order to participate in the Rights Issue in relation to any vested options that you hold, you must exercise those options by 5.00 pm on Monday 11[th] August 2008. Please note that only vested options may be exercised.

Please note that it is not compulsory to exercise your vested options. If you do wish to exercise your vested options, you may do so by completing all of the steps required by the terms and conditions of the options, including payment of the relevant exercise price. Exercise must occur by 5.00 pm on Monday 11[th] August 2008 so that the Company is able to allot and issue your shares in time for you to participate in the Rights Issue.

If you have any questions in relation to your options please contact Link Market Services on 1300 554 474.

Yours sincerely,

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Brad O’Connor

Chief Executive Officer