Celyad Oncology : Security Note

DocuSign Envelope ID: 780E1CBA-3E9B-4DC4-8F77-FFA905801961

Listing and admission to trading on Euronext Brussels and Euronext Paris of up to 2,588,977

new shares

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 2,588,977 new shares with ISIN number BE0974260896-XBRU (the "New Shares") on the regulated markets of 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 21 June 2022, and subsequently passported 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 7 June 2022 (the "Registration Document"); and
• the Company's summary note in relation to the admission to trading of up to 2,588,977 New Shares on Euronext Brussels and Euronext Paris, as approved by the FSMA on 21 June 2022 and as subsequently passported 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 Celyad's shares (the "Shares") involves a high degree of risk and uncertainties. Prospective investors should read the entire Prospectus, and, in particular, should refer to the chapter "Risk factors" for a discussion of certain factors that should be considered in connection with an investment in the Shares, including the risks that (i) Celyad will need substantial additional funding, which may not be available on acceptable terms when needed, if at all, (ii) the Company's drug product candidates are new approaches to cancer treatment that present significant challenges and that shall be approved by applicable authorities (being noted that no product has been approved nor commercialised yet), (iii) in previous clinical trials involving T cell-based immunotherapies, some patients experienced serious adverse events, the Company's drug product candidates may demonstrate a similar effect or have other properties that could halt their clinical development, prevent their regulatory approval, limit their commercial potential, or result in significant negative consequences and (iv) Celyad has incurred net losses in each period since its inception and anticipates that it will continue to incur net losses in the future. In the chapter "Risk factors", although the risk factors are not necessarily all ranked in order of their materiality, in each category the risk factors which in the assessment of Celyad are the most material, taking into account the negative impact on Celyad and the probability of its occurrence, are mentioned first.

All these factors should be considered before investing in the Shares and 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.

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Pursuant to article 21.8 of the Prospectus Regulation, this prospectus has a 12 months validity and will expire on 20 June 2023. 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 existing Shares of the Company are already admitted to listing and trading on Euronext Brussels and Euronext Paris.

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	Future sales of substantial amounts of Shares, or the perception that such sales could occur,
	could adversely affect the market value of the Shares..............................................................	7
1.3	Certain significant shareholders of the Company may have different interests from	the
	Company and may be able to control the outcome of shareholder votes ..................................	7
1.4	Sustainability of a liquid public market...................................................................................	7

1.5 If securities or industry analysts do not publish research or publish inaccurate research or unfavourable research about the Company's business, the price of the Shares and trading

	volume could decline..............................................................................................................	8
1.6	The Company will likely not be in a capacity to pay dividends in the foreseeable future and
	intends to retain all earnings ...................................................................................................	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	Capitalisation and indebtedness ............................................................................................	14

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3.2	Working capital statement ....................................................................................................	15
3.3	Reason for the capital increase and use of proceeds...............................................................	15
3.4	Interest of natural and legal persons involved in the issue .....................................................	16
3.5	Significant change in the financial position of Celyad since 31 December 2021 ....................	16
4.	DESCRIPTION OF THE NEW SHARES TO BE ADMITTED TO TRADING...............	18
4.1	Authorised Capital................................................................................................................	18
4.2	The issuance 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..............................................................................................	21
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.......................................................	23
	Dividend rights ...........................................................................................................	26
	Rights regarding liquidation ........................................................................................	27
	Changes to the share capital ........................................................................................	27
	Purchase and sale of own Shares .................................................................................	28
	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........................................................................................................................	32
4.8	Taxation in Belgium.............................................................................................................	32
	Overview ....................................................................................................................	32
	Taxation on dividends on Shares .................................................................................	32
	Taxation on capital gains and losses on shares.............................................................	38
	Tax on stock exchange transactions.............................................................................	40
	Tax on Securities Accounts (TSA) ..............................................................................	41

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4.9	Taxation in France................................................................................................................	41
	Dividends....................................................................................................................	42
	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 ............................................................	52

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