INVESTOR ALERT: Class Action Lawsuit Filed on Behalf of Atara Biotherapeutics, Inc. (ATRA) Investors – Holzer & Holzer, LLC Encourages Investors With Significant Losses to Contact the Firm

Group 1 - A shareholder class action lawsuit has been filed against Atara Biotherapeutics, alleging false and misleading statements regarding its business and operations [1] - The lawsuit claims that manufacturing issues and deficiencies in the ALLELE study make FDA approval of tabelecleucel unlikely, overstating its regulatory prospects [1] - The alleged manufacturing issues also increase the risk of regulatory scrutiny and jeopardize ongoing clinical trials, likely impacting Atara's business and financial condition negatively [1] Group 2 - Shareholders who purchased Atara shares between May 20, 2024, and January 9, 2026, and experienced significant losses are encouraged to discuss their legal rights [2] - The deadline to request appointment as lead plaintiff in the case is May 22, 2026 [3] - Holzer & Holzer, LLC is a law firm specializing in shareholder class action litigation and has recovered hundreds of millions for shareholders affected by corporate misconduct [3]