Mont-Saint-Guibert, Belgium, September 15, 2023, 10:01 p.m. CET – regulated information – Celyad Oncology SA (Euronext: CYAD) (“Celyad Oncology” or the “Company”), announced today, in accordance with article 14 of the Belgian law of May 2, 2007 relating to the publication of significant participations in issuers whose shares are admitted to trading on a regulated market (the “Transparency Law”), have received a rectified transparency notification dated September 13 2023 indicating that CFIP CLYD (UK) Limited, a subsidiary of Fortress Investment Group LLC, has crossed the statutory threshold of 25%, holding 7,954,808 shares, representing 29.99% of the shares of Celyad Oncology and 27.53% of the rights voting on September 4, 2023. This press release replaces that of September 7, 2023.