Issue of Equity

Horizon Discovery Group plc

Issue of Equity

Cambridge, UK, 7 October 2015: Horizon Discovery Group plc (LSE: HZD) ("Horizon" or the "Company"), the international life science company supplying research tools and services that power genomics research and the development of personalised medicines, today announces that, further to the announcement made on 29 September 2014, the conditions for the issue of additional new ordinary shares of 1p each in the Company (the "Deferred Consideration Shares") to former stockholders of Sage Labs Inc. ("Sage") twelve months after the closing of the acquisition of Sage by Horizon pursuant to a Merger Agreement dated 26 September 2014 (the "Merger Agreement") have been satisfied.

Horizon has approved the allotment and issue of the 576,730 Deferred Consideration Shares to the former stockholders of Sage under the Merger Agreement, and an application has been made for the admission to trading on AIM of the Deferred Consideration Shares ("Admission"). Admission is expected to take place on or about 8 October 2015. The Deferred Consideration Shares will rank pari passu in all respects with Horizon's existing shares in issue.

Following Admission, the Company's enlarged issued share capital will comprise 94,082,081 Ordinary Shares with one voting right per share. No shares are held in Treasury. The total number of voting rights in the Company is therefore 94,082,081. This figure of 94,082,081 ordinary shares may be used by shareholders in the Company as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change in their interest in, the share capital of the Company under the FCA's Disclosure and Transparency Rules.

The subsequent sale of any Deferred Consideration Shares will be subject to orderly market arrangements, identical to those dictated in the Merger Agreement for the initial consideration shares.

ENDS

Contacts:

For further information from Horizon Discovery Group plc, please contact:

Horizon Discovery Group plc

Dr. Darrin Disley CEO / Richard Vellacott CFO

Tel: +44 (0) 1223 655580

Consilium Strategic Communications (Financial Media and Investor Relations)

Amber Fennell / Jessica Hodgson / Matthew Neal / Laura Thornton

Tel: +44 (0) 20 3709 5701

Email: [email protected]

Panmure Gordon & Co. (NOMAD)

Corporate Finance: Freddy Crossley / Fabien Holler / Duncan Monteith

Corporate Broking: Tom Salvesen

Tel: +44 20 7886 2500

About Horizon Discovery Group plc www.horizondiscovery.com/

Horizon is a revenue-generating life science group supplying research tools to organisations engaged in translational genomics research and the development of personalised medicines. Horizon has a diverse and international customer base of over 1,200 organisations across more than 50 countries, including major pharmaceutical, biotechnology and diagnostic companies as well as leading academic research centers. The Group supplies its products and services into multiple markets, estimated to total in excess of £29 billion by 2015.

Horizon's core capabilities are built around its proprietary translational genomics platform, a high-precision and flexible suite of gene editing tools able to alter almost any endogenous gene sequence of human or mammalian cell-lines. Horizon offers over 20,000 catalogue products, almost all of which are based on the application of gene editing to generate cell lines that accurately model the disease-causing mutations found in genetically based diseases. These 'patients-in-a-test-tube' are being used by customers to identify the effect of individual or compound genetic mutations on drug activity, patient responsiveness, and resistance, which may lead to the successful prediction of which patient sub-groups will respond to currently available and future drug treatments.

In addition, Horizon provides custom cell line and in vivo model generation services for research and bioproduction applications, quantitative molecular reference standards, in vivo disease models, and contract research and custom screening services.

Horizon is headquartered in Cambridge, UK, and is listed on the London Stock Exchange's AIM market under the ticker "HZD", for further information please visit: www.horizondiscovery.com.