Celyad Oncology SA

Declaration of Voting Results & Voting Rights Announcements • Aug 7, 2025

InformationontheTotalNumberofVotingRightsand Shares (Article15oftheLawof2May2007)

Mont-Saint-Guibert, Belgium; August 7, 2025, 06:30 pm CET; regulated information – Celyad Oncology (Euronext: CYAD) (the "Company" or "Celyad Oncology"), today announces the below information following the issuance, on August 5, 2025, of 3,333,333 new shares of Celyad Oncology to an affiliate of Fortress Investment Group. As a result, the Company's share capital has been increased to 9,216,154.53 EUR and is represented by 44,761,905 shares.

This information is published in accordance with Article 15 of the Belgian Law of 2 May 2007 on the disclosure of major participations in issuers whose shares are admitted to trading on a regulated market and regarding miscellaneous provisions.

Total amount of share capital (EUR)	9,216,154.53
Total Number of shares with single voting rights	35,893,530
Total Number of shares with double voting rights	8,868,375
Total Number of Shares	44,761,905
Total of voting rights	53,630,280
Total number of attributed warrants	3,856,134
Total number of shares with voting rights that could	3,856,134
be created following the exercise of the attributed
warrants
Totalnumberofdilutedshares (Outstandingshares+	48,618,039
Warrants)
Total number of diluted shares with voting rights	57,486,414

Figures – Modified onAugust 5, 2025,following the capital increase:

Contactperson forregulated information (financial, transparency)

By law, any transparency declaration must be sentto ourCompany by emailto the attention of Matthew Kane, Chief Executive Officer (CEO): investors@celyad.com.

Further questions aboutthe content ofthis release can be sentto investors@celyad.com.

About Celyad Oncology

Celyad Oncology is a cutting-edge biotechnology company focused primarily on unlocking the potential of its proprietary CAR-T technology platforms and intellectual property. The Company is headquartered in Mont-Saint-Guibert, Belgium. For more information, visit www.celyad.com.

Celyad Oncology Forward-Looking Statement

This release may contain forward-looking statements, including, without limitation, statements regarding beliefs about and expectations for the Company's updated strategic business model, including associated potential benefits, transactions and partnerships, statements regarding the potential value of the Company's IP, statements regarding the Company's financial statements and cash runway, statements regarding the Company's future fundraising plans, statements regarding the Company's hiring plans, and statements regarding the continuation of the Company's existence. The words "will," "potential," "continue," "target," "project," "should" and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements in this release are based on management's current expectations and beliefs and are subject to a number of known and unknown risks, uncertainties and important factors which might cause actual events, results, financial condition, performance or achievements of Celyad Oncology to differ materially from those expressed or implied by such forward-looking statements. Such risks and uncertainties include, without limitation, risks related to the material uncertainty about the Company's ability to continue as a going concern; the Company's ability to realize the expected benefits of its updated strategic business model; the Company's ability to develop its IP assets and enter into partnerships with outside parties; the Company's ability to enforce its patents and other IP rights; the possibility that the Company may infringe on the patents or IP rights of others and be required to defend against patent or other IP rights suits; the possibility that the Company may not successfully defend itself against claims of patent infringement or other IP rights suits, which could result in substantial claims for damages against the Company; the possibility that the Company may become involved in lawsuits to protect or enforce its patents, which could be expensive, time-consuming, and unsuccessful; the Company's ability to protect its IP rights throughout the world; the potential for patents held by the Company to be found invalid or unenforceable; and other risks identified in the latest Annual Report ofCelyad Oncology. These forward-looking statements speak only as of the date of publication of this document and Celyad Oncology's actual results may differ materially from those expressed or implied by these forward-looking statements. Celyad Oncology expressly disclaims any obligation to update any such forward-looking statements in this document to reflect any change in its expectations with regard thereto or any change in events, conditions or circumstances on which any such statement is based, unless required by law or regulation.

Investor & Media Contact:

David Georges, VP Finance and Administration investors@celyad.com