Celyad Oncology : Security Note

SECURITIES NOTE

This Securities Note (the "Securities Note") has been prepared by Celyad Oncology SA (the "Company" or "Celyad") in relation to the admission to trading of up to 2,595,777 new shares with ISIN number BE0974260896-XBRU (the "New Shares") on Euronext Brussels and Euronext Paris. This Securities Note has been approved by the Belgian Financial Services and Markets Authority (Autorité des services et marches financiers, the "FSMA") on 8 June 2021, and consequently notified to the French Financial Markets Authority (Autorité des Marchés Financiers, the "AMF"), and should be read in conjunction with the following documents:

• The Company's registration document as approved by the FSMA on 1st June 2021 (the "Registration Document"); and
• the Company's summary note in relation to the admission to trading of up to 2,595,777 new shares on Euronext Brussels and Euronext Paris, as approved by the FSMA on 8 June 2021 and as subsequently notified to the AMF (the "Summary Note").

The Registration Document and the Summary Note, together with this Securities Note, constitute a prospectus within the meaning of article 10 of the Prospectus Regulation 2017/1129 (the "Prospectus Regulation"). This Securities Note contains the minimal disclosure requirement for a share securities note in accordance with Annex 12 of the Prospectus Regulation.

Investing in the New Shares involves a high degree of risk. An investor is exposed to the risk to lose all or part of his/her investment. Celyad is a biotech company which undertakes clinical trials that have not led to the commercialisation of any products yet and which has never been profitable. Previous positive results are no guarantee for success in subsequent studies, for regulatory approval and for market acceptance. The outbreak of the novel coronavirus (COVID-19) or any other infectious disease outbreak or other serious public health concern could result in delays to Celyad's clinical studies and could adversely affect its supply chain and work force. Investors are advised to carefully consider the information contained in the whole prospectus and, in particular, the risks described in the section "Risk Factors". Investors must be able to bear the economic risk of an investment in shares and should be able to sustain a partial or total loss of their investment.

Pursuant to article 21.8 of the Prospectus Regulation, this prospectus has a 12 months validity and will expire on 8 June 2022. In accordance with article 23 of the Prospectus Regulation, the obligation to supplement a prospectus does not longer apply when a prospectus is no longer valid.

No offer to the public of the New Shares will be made in Belgium, France or in any other member state of the European Economic Area that has implemented the Prospectus Regulation and no one has taken any action that would, or is intended to, permit an offer to the public of the New Shares in any country or jurisdiction where any such action for such purpose is required.

The Board of Directors of Celyad assumes responsibility for the content of the Prospectus. The Board of Directors declares that, to the best of its knowledge, the information contained in this Prospectus is in accordance with the facts and that the Prospectus makes no omission likely to affect its import.

On behalf of the Board of Directors,

______________________________

Filippo Petti Managing Director

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TABLE OF CONTENTS
1. RISK FACTORS RELATED TO THE SHARES....................................................................	6
1.1 The market price of the Shares may fluctuate widely in response to various factors.................	6

1.2 If securities or industry analysts do not publish research or publish inaccurate research or unfavourable research about its business, the price of the securities and trading volume could

	decline.........................................................................................................................................	7
1.3	The market price of the Shares could be negatively impacted by actual or anticipated sales of
	substantial numbers of Shares ...................................................	Error! Bookmark not defined.
1.4	Sustainability of a liquid public market......................................................................................	8
1.5	The Company has no present intention to pay dividends on its Shares in the foreseeable future
	....................................................................................................................................................	8
2. GENERAL INFORMATION ....................................................................................................	9
2.1	Introduction ................................................................................................................................	9
	The Prospectus - No offer to the public in Belgium, France or through Euronext	.......... 9
	Language of the Prospectus ............................................................................................	10
	Availability of the Prospectus .........................................................................................	10
2.2	Persons responsible for the contents of the Prospectus ............................................................	10
2.3	Approval of the Prospectus.......................................................................................................	11
2.4	Other available information ......................................................................................................	11
2.5	Notice to investors ....................................................................................................................	12
	Decision to invest............................................................................................................	12
	Forward looking statements ............................................................................................	12
	Market and Industry Information....................................................................................	13
	Rounding of financial and statistical information...........................................................	13
3. ESSENTIAL INFORMATION................................................................................................	14
3.1	Working capital statement ........................................................................................................	14
3.2	Reason for the capital increase and use of proceeds.................................................................	15
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3.3	Interest of natural and legal persons involved in the issue .......................................................	17
3.4	Significant change in the financial position of Celyad since 31 December 2020.....................	17
4. DESCRIPTION OF NEW SHARES TO BE ADMITTED TO TRADING ........................	18
4.1	Authorised Capital ....................................................................................................................	18
4.2	The issue of the New Shares.....................................................................................................	19
4.3	Standstill and lock-up ...............................................................................................................	20
4.4	Issue price of the New Shares...................................................................................................	20
4.5	Description of the New Shares .................................................................................................	20
4.6	Rights attached to the Shares of the Company .........................................................................	21
	Preferential subscription rights .......................................................................................	21
	Voting rights attached to Shares .....................................................................................	21
	Right to attend and vote at shareholders' meetings ........................................................	22
	Dividend rights ...............................................................................................................	26
	Rights regarding liquidation ...........................................................................................	27
	Changes to the share capital............................................................................................	27
	Purchase and sale of own Shares ....................................................................................	27
	Relevant legislation.........................................................................................................	28
	American Depositary Shares...........................................................................................	31
4.7	Takeover bids instigated by third parties during the previous financial year and the current
	financial year ............................................................................................................................	31
4.8	Taxation in Belgium .................................................................................................................	31
	Overview.........................................................................................................................	31
	Taxation on dividends on Shares ....................................................................................	32
	Taxation on capital gains and losses on shares ...............................................................	38
	Tax on stock exchange transactions................................................................................	40
4.9	Taxation in France ....................................................................................................................	41
	Dividends ........................................................................................................................	42

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	Capital gains ...................................................................................................................	44
	Wealth Tax......................................................................................................................	45
	Financial transactions tax................................................................................................	45
	Registration duties (droits d'enregistrement)..................................................................	45
5.	ADMISSION TO TRADING ...................................................................................................	47
6.	DILUTION.................................................................................................................................	48
6.1	Evolution of the share capital of the Company.........................................................................	48
6.2	Financial consequences for the existing shareholders ..............................................................	51

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