Statement re Horizon Discovery Group plc

NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION IN WHOLE OR IN PART IN, INTO OR FROM ANY JURISDICTION WHERE TO DO SO WOULD CONSTITUTE A VIOLATION OF THE RELEVANT LAWS OF SUCH JURISDICTION

THIS IS AN ANNOUNCEMENT FALLING UNDER RULE 2.8 OF THE CITY CODE ON TAKEOVERS AND MERGERS (THE "CODE")

THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION

FOR IMMEDIATE RELEASE

09 May 2018

Abcam plc

Statement re Horizon Discovery Group plc ("Horizon Discovery")

On 2 May 2018, Abcam plc ("Abcam") announced that it had made a proposal in relation to a possible offer for Horizon Discovery at 181 pence per share (the "Proposal"). This reflected Abcam's strong interest in pursuing strategic expansion in the gene editing market, which the Directors of Abcam believe to be a highly complementary adjacency to Abcam's existing business. The Proposal was rejected by the Board of Horizon Discovery.

Abcam continues to execute on its vision to be the most influential life science company for researchers worldwide, and remains committed to expanding its reach and influence globally. However, it has always been Abcam's intention to remain disciplined about value whilst working towards a transaction with the recommendation of the Board of Horizon Discovery.

On 8 May 2018, Horizon Discovery published its preliminary results for the year ended 31 December 2017. Having considered those results and Horizon Discovery's statement on 2 May 2018 regarding the Board of Horizon Discovery's view that there is little strategic rationale to combining the two companies, Abcam confirms that it does not intend to make an offer for Horizon Discovery.

This is a statement to which Rule 2.8 of the Code applies. Under Note 2 on Rule 2.8 of the Code, Abcam, and any person acting in concert with Abcam, reserves the right to set the restrictions in Rule 2.8 aside in the following circumstances:

a) with the agreement of the board of Horizon Discovery;

b) if a third party announces a firm intention to make an offer for Horizon Discovery;

c) if Horizon Discovery announces a "whitewash" proposal (see Note 1 of the Notes on Dispensations from Rule 9) or a reverse takeover (as defined in the Code); and/or

d) if there has been a material change of circumstances (as determined by the Panel).

In accordance with Rule 26.1 of the Code, a copy of this announcement will be available on the Abcam website at www.abcamplc.com by no later than 12-noon (London time) on the business day following this announcement.

About Abcam plc

As an innovator in reagents and tools, Abcam's purpose is to serve life science researchers globally to achieve their mission, faster. Providing the research and clinical communities with tools and scientific support, the Group offers highly validated biological binders and assays to address important targets in critical biological pathways.

Founded in 1998 and headquartered in Cambridge, UK, Abcam serves researchers in over 130 countries, from eleven locations around the world. Since admission to AIM in 2005 (AIM: ABC). Abcam's revenues have grown 15 fold to £217m (FY2017) and profits 20 fold. Over the same period, its market capitalisation has risen 38 fold to c.£2.5 billion (1 May 2018).

Already a pioneer in data sharing and ecommerce in the life sciences, Abcam's ambition is to be the most influential company in life sciences by helping advance global understanding of biology and causes of disease, which, in turn, will drive new treatments and improved health. Two-thirds of the world's 750,000 life science researchers use Abcam's antibodies and affinity binders, reagents, biomarkers and assays.

By actively listening to and collaborating with researchers, the Group continuously advances its portfolio to address their needs. A transparent programme of customer reviews and datasheets, combined with an industry-leading validation initiative, gives researchers increased confidence in their results.

Important Notices

Ondra LLP, which is regulated in the United Kingdom by the Financial Conduct Authority, is acting as joint financial adviser exclusively for Abcam and no one else in connection with the matters set out in this announcement and will not regard any other person as its client in relation to the matters set out in this announcement and will not be responsible to anyone other than Abcam for providing the protections afforded to clients of Ondra LLP, nor for providing advice in relation to any matter referred to herein.

J.P. Morgan Securities plc, which conducts its UK investment banking business as J.P. Morgan Cazenove ("J.P. Morgan Cazenove"), is authorised in the United Kingdom by the Prudential Regulation Authority (the "PRA") and regulated in the United Kingdom by the PRA and the Financial Conduct Authority. J.P. Morgan Cazenove is acting as joint financial adviser exclusively for Abcam and no one else in connection with the matters set out in this announcement and will not regard any other person as its client in relation to the matters set out in this announcement and will not be responsible to anyone other than Abcam for providing the protections afforded to clients of J.P. Morgan Cazenove or its affiliates, nor for providing advice in relation to any matter referred to herein.

The release, publication or distribution of this announcement in jurisdictions outside the United Kingdom may be restricted by law and, therefore, persons into whose possession this announcement comes should inform themselves about, and observe, such restrictions. Any failure to comply which such restrictions may constitute a violation of the securities law of any such jurisdiction.