Celyad Oncology SA — Proxy Solicitation & Information Statement 2023

Sep 22, 2023

CELYAD ONCOLOGY SA Listed limited liability company

Rue Edouard Belin, 2 1435 Mont-Saint-Guibert

LER Nivelles 0891.118.115

(the "Company")

INFORMATION CONCERNING THE RIGHTS OF SHAREHOLDERS PURSUANT TO ARTICLES ARTICLE 7:130 OF THE CODE OF COMPANIES AND ASSOCIATIONS ON THE OCCASION OF THE EXTRAORDINARY MEETING OF THE COMPANY TO BE HELD ON 25 OCTOBER 2023 AT 2 PM AT THE COMPANY'S REGISTERED OFFICE

1. RIGHT OF SHAREHOLDERS TO INCLUDE ITEMS ON THE AGENDA AND TO SUBMIT DECISIONS' PROPOSALS

In accordance with article 7:130 of the Companies and Associations Code, one or more shareholders holding together at least 3% of the share capital may request the inclusion of items on the agenda to be addressed at the general meeting and request the submission of decisions' proposals concerning items to be addressed or included on the agenda.

The shareholder or shareholders exercising this right must, in order for their request to be examined at the general meeting, satisfy the following two conditions:

• prove that they hold the abovementioned required percentage on the date of their request (either by way of a certificate mentioning the registration of the corresponding shares on the Company's share register, or by way of an attest of a settlement institution or a certified account holder setting out the number of corresponding dematerialised shares registered in its accounts under the name of the shareholder); and
• still be a shareholder for up to 3% of the Company's share capital on the record date (11 October 2023 at midnight (Belgian time)).

Shareholders may then exercise their right by submitting (i) the draft new items for the agenda, and/or (ii) the draft proposals for resolution to be reflected in the agenda. Items to be included on this agenda and/or decisions' proposals must be sent to the Company on 3 October 2023 at the latest by email to investors@celyad.com, or by mail marked for the attention of Celyad Oncology SA, Mrs. An Phan, Head of Legal, Rue André Dumont 9, B-1435 Mont-Saint-Guibert.

The Company will acknowledge receipt of the requests sent by email or by mail to the address indicated by the shareholder within 48 hours after receipt.

The revised agenda will be published on 10 October 2023 at the latest (on the Company's website at the address www.celyad.com, in the Belgian Official Gazette and in the press) if one or more requests to include new items or proposals for decisions on the agenda have been received within the aforementioned deadline.

Further information relating to the abovementioned rights and the modalities for exercising them are available on the Company's website (www.celyad.com).

2. RIGHT OF SHAREHOLDERS TO ASK WRITTEN QUESTIONS

Shareholders may ask questions exclusively in writing before the meeting, concerning the report of the board of directors or the agenda of the meeting. The Company will answer the questions during the meeting.

The exercise of this right is subject to the fulfilment of the following two conditions:

• being a shareholder of the Company on the record date (11 October 2023 at midnight (Belgian time)); and
• having informed the Company of the intent to participate in the general meeting, pursuant to the provisions set out in the convening notice.

The questions can be sent prior to the general meeting by email to the address investors@celyad.com or by mail marked for the attention of Celyad Oncology SA, Mrs. An Phan, Head of Legal, Rue André Dumont 9, B-1435 Mont-Saint-Guibert.

Those questions must be received by the Company on 19 October 2023 at 17h00 (CET) at the latest.

In accordance with applicable legal provisions, the directors answer questions that are asked by the shareholders during the meeting or that have been asked in writing prior to the meeting, during the general meeting on their report or on the agenda. The auditor also answers questions asked by the shareholders at the meeting or in writing prior to the meeting on its report.

Further information relating to the abovementioned right and the modalities for exercising them are available on the Company's website (www.celyad.com).