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, 18 January 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 FMR LLC on 16 and 17 January 2018.

FMR LLC (taking into account the holdings of its subsidiary undertakings) now holds a total of 7,230,164 voting securities of Ablynx, representing 9.68% of the current 74,720,644 outstanding voting rights of Ablynx (versus 9.50% notified previously on 25 August 2017).

FMR LLC has notified Ablynx that FMR Co., Inc., a subsidiary of Fidelity Management & Research Company, which itself is a subsidiary of FMR LLC (the ultimate parent company) has downward crossed the 5% threshold of voting rights of Ablynx since 15 January 2018 and upward crossed the 3% threshold of voting rights held through financial instruments since 16 January 2018.

The notification contains the following information:

• Reason for the notification:
  • acquisition or disposal of voting securities or voting rights
  • 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: FMR LLC
• Transaction date: 15 and 16 January 2018
• Threshold that is crossed: 5% of voting rights and 3% of voting rights held through financial instruments
• Denominator: 74,720,644
• Details of the notification:

Name of select subsidiaries of FMR LLC	% of voting rights	% of voting rights held through financial instruments*	Total of both
FMR LLC Fidelity Management & Research Company FMR Co., Inc.	4.41%	3.21%	7.62%
FMR LLC FIAM Holdings Corp. Fidelity Institutional Asset Management Trust Company	1.05%		1.05%
FMR LLC