Celyad Oncology SA

Publication of a Transparency Notification Received from Tolefi SA

Regulatory News:

Celyad Oncology SA (Euronext: CYAD) (“Celyad Oncology” or the “Company”) 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 transparency notification dated September 8, 2023, from Tolefi SA and related persons indicating that they have jointly crossed the 20% threshold, holding 6,568,978 shares, or 22.74% of the voting rights of the Company as of September 4, 2023.

Content of the Notification:

• Reason of the Notification:
  Threshold crossing by persons acting in concert

• Notification by:
  Persons acting in concert

• Persons subject to the notification requirement:
  Tolefi SA, Chaussée de Waterloo 1589D, 1180 Uccle
  Serge Goblet
  Isabelle Thoumyre
  Jérôme Goblet
  Jean-Daniel Goblet

• Date on which the threshold is crossed:
  September 4, 2023

• Threshold that is crossed (in %):
  20

• Denominator:
  28,893,101

• Notified details:

A) Voting Rights		Previous notification		After the Transaction
		#of voting rights		# of voting rights				% of voting rights
Holders of voting rights				Linked to the securities		Not linked to the securities		Linked to the securities		Not linked to the securities
Tolefi SA		4,591,402		6,504,864		0