PUBLICATION IN ACCORDANCE WITH ARTICLE 14 OF THE BELGIAN LAW OF 2 MAY 2007 REGARDING THE PUBLICATION OF MAJOR SHAREHOLDINGS (THE "TRANSPARENCY LAW")

REGULATED INFORMATION

GHENT, Belgium, 12 March 2018 - Ablynx [Euronext Brussels and Nasdaq: ABLX] today announced, in accordance with Article 14 of the Belgian Law of 2 May 2007 regarding the publication of major shareholdings in issuers whose securities are admitted to trading on a regulated market (the "Transparency Law"), that it received a notification of shareholdings from BlackRock, Inc. on 8 March 2018.

BlackRock, Inc. (taking into account the holdings of its subsidiary undertakings) notified Ablynx that it has downward crossed the 3% threshold of voting rights held through financial instruments since 6 March 2018 and now holds a total of 3,414,448 voting securities of Ablynx, representing 4.55% of the current 75,073,886 outstanding voting rights of Ablynx (versus 4.04% notified previously on 23 February 2018).

The notification contains the following information:

• Reason for the notification: acquisition or disposal of financial instruments that are treated as voting securities
• Notification by: a parent undertaking or a controlling person
• Persons subject to the notification requirement:

• Transaction date: 6 March 2018
• Threshold that is crossed: 3% of voting rights held through financial instruments
• Denominator: 75,073,886
• Details of the notification:

* Type of financial instrument: ¹'Securities lent' and ²'Contract for Difference'

• Chain of controlled undertakings through which the holding is effectively being held: Please see the full chain of control in the Transparency Notification.
• Additional information: The disclosure obligation arose due to voting rights through financial instruments for BlackRock, Inc. going below 3%.

A full version of the transparency notification is available on Ablynx website, under the section Investors.

The Articles of the Association of Ablynx NV provide for shareholders notification threshold of 3%, 5% or a multiple of 5% of the total number of existing voting rights.

About Ablynx

Ablynx is a biopharmaceutical company engaged in the development of Nanobodies, proprietary therapeutic proteins based on single-domain antibody fragments, which combine the advantages of conventional antibody drugs with some of the features of small-molecule drugs. Ablynx is dedicated to creating new medicines which will make a real difference to society. Today, the Company has more than 45 proprietary and partnered programmes in development in various therapeutic areas including inflammation, haematology, immuno-oncology, oncology and respiratory disease. The Company has collaborations with multiple pharmaceutical companies including AbbVie; Boehringer Ingelheim; Eddingpharm; Merck & Co., Inc., Kenilworth, New Jersey, USA; Merck KGaA; Novo Nordisk; Sanofi and Taisho Pharmaceuticals. The Company is headquartered in Ghent, Belgium. More information can be found on www.ablynx.com.

For more information, please contact
Ablynx:
Dr Edwin Moses
CEO
t:   +32 (0)9 262 00 07
m: +32 (0)473 39 50 68
e:  edwin.moses@ablynx.com

Lies Vanneste
Director Investor Relations
t:   +32 (0)9 262 01 37
m: +32 (0)498 05 35 79
e:  lies.vanneste@ablynx.com

Follow us on Twitter @AblynxABLX

Ablynx media relations:
Consilium Strategic Communications
Mary-Jane Elliott, Philippa Gardner, Sukaina Virji
t:  +44 (0)20 3709 5700
e:  ablynx@consilium-comms.com

Joele Frank, Wilkinson Brimmer Katcher
Dan Katcher or Joseph Sala
t:  +1 212-355-4449