Completion of Acquisition

THIS ANNOUNCEMENT AND THE INFORMATION CONTAINED HEREIN IS RESTRICTED AND, SUBJECT TO CERTAIN EXCEPTIONS, IS NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, IN WHOLE OR IN PART, DIRECTLY OR INDIRECTLY IN, OR INTO OR FROM THE UNITED STATES, AUSTRALIA, CANADA (EXCEPT IN COMPLIANCE WITH CANADIAN SECURITIES LAWS), JAPAN, NEW ZEALAND, THE REPUBLIC OF IRELAND OR THE REPUBLIC OF SOUTH AFRICA OR ANY OTHER JURISDICTION IN WHICH THE SAME WOULD BE UNLAWFUL.

FURTHER, THIS ANNOUNCEMENT IS FOR INFORMATION PURPOSES ONLY AND SHALL NOT CONSTITUTE AN OFFER TO SELL OR ISSUE OR THE SOLICITATION TO BUY, SUBSCRIBE FOR OR OTHERWISE ACQUIRE ANY ORDINARY SHARES OF HORIZON IN ANY JURISDICTION IN WHICH ANY SUCH OFFER OR SOLICITATION WOULD BE UNLAWFUL. THIS ANNOUNCEMENT SHOULD BE READ IN ITS ENTIRETY.

THE SECURITIES REFERRED TO HEREIN MAY NOT BE OFFERED OR SOLD IN THE UNITED STATES ABSENT REGISTRATION OR AN EXEMPTION FROM REGISTRATION UNDER THE U.S. SECURITIES ACT OF 1933, AS AMENDED. THE COMPANY DOES NOT INTEND TO REGISTER ANY OF THE SECURITIES IN THE UNITED STATES OR TO CONDUCT A PUBLIC OFFERING OF THE SECURITIES IN THE UNITED STATES.

Horizon Discovery Group plc ("Horizon" or the "Company")

Completion of Acquisition

Cambridge, UK, 31 August 2017: Horizon Discovery Group plc (LSE: HZD) ("Horizon" or "the Company") is pleased to announce that, further to the Company's announcement on 22 August 2017, the acquisition of GE Healthcare Dharmacon, Inc. ("Dharmacon") completed today and the admission to trading on AIM of the 13,064,868 new ordinary shares of 1 pence each (the "Consideration Shares") is expected to take place at 8.00 a.m. on 1 September 2017.

Dr. Darrin M Disley, CEO of Horizon Discovery, commented: "We are delighted to have completed the transformational acquisition of Dharmacon and look forward to working closely with our new colleagues and providing an expanded array of research solutions to a cumulative customer base now exceeding 10,000 in number. Dharmacon is a global leader in gene modulation products with a fast growing gene-editing product portfolio which are highly complementary to the gene editing, translational genomics, personalised medicine, cell and gene therapy products and services of Horizon. The combined business creates a global leader in the application of gene modulation and gene editing technologies - two rapidly growing and important areas of life science research.

"We expect the strong commercial synergies in markets, sales channels, and brand strength to accelerate revenue growth and margin expansion for the product portfolios of the enlarged business, with additional opportunities to realise operational efficiencies that are intended to drive significant cost savings and EBITDA expansion as we continue to scale.

"The placing of £80 million was significantly oversubscribed and we were pleased that both existing and new UK investors strongly supported the acquisition. Furthermore Horizon is delighted to welcome a significant number of new blue-chip international shareholders including GE Healthcare and many specialist US healthcare investors to the shareholder register."

Following admission of the Consideration Shares, the Company's issued share capital will comprise 148,915,950 ordinary shares of 1 pence each, with voting rights. Horizon does not hold any shares in treasury. This figure of 148,915,950 ordinary shares may be used by shareholders in Horizon to determine if they are required to notify their interest in, or a change in their interest in, Horizon under the Financial Conduct Authority's Disclosure and Transparency Rules.

ENDS

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

Horizon Discovery Group plc

Darrin Disley, Chief Executive Officer

Richard Vellacott, Chief Financial Officer

Chris Claxton, VP Investor Relations

Tel: +44 (0) 1223 655 580

Numis Securities Limited (Broker and NOMAD)

Michael Meade / Freddie Barnfield

Tel: +44 (0) 207 260 1000

Consilium Strategic Communications (Financial Media and Investor Relations)

Mary-Jane Elliott / Susan Stuart / Matthew Neal / Melissa Gardiner

Tel: +44 (0) 20 3709 5701

Email: [email protected]

About Horizon Discovery Group plc - see www.horizondiscovery.com

Horizon Discovery Group plc (LSE: HZD) ("Horizon") is a world leader in gene editing and gene modulation technologies. Horizon designs and engineers cells using its translational genomics platform, a highly precise and flexible suite of DNA editing tools (rAAV, ZFN, CRISPR and Transposon) and, following the acquisition of Dharmacon, its functional genomics platform comprising gene knockdown (RNAi) and gene expression (cDNA, ORF) tools, for research and clinical applications that advance human health. Horizon's platforms and capabilities enable researchers to alter almost any gene or modulate its function in human or mammalian cell-lines.

Horizon offers an extensive range of catalogue products and related research services to support a greater understanding of the function of genes across all species and the genetic drivers of human disease and the development of personalised molecular, cell and gene therapies. These have been adopted by over 10,000 academic, drug discovery, drug manufacturing and clinical diagnostics customers around the globe, as well as in the Company's own R&D pipeline.

Horizon is headquartered in Cambridge, UK, and is listed on the London Stock Exchange's AIM market under the ticker "HZD".