Welcome to our dedicated page for Atara Biotherapeutics SEC filings (Ticker: ATRA), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
Atara Biotherapeutics' SEC filings document the company's allogeneic EBV T-cell immunotherapy business, public common stock, and regulatory record for tabelecleucel, including 8-K disclosures tied to FDA communications, Complete Response Letter updates, and the EBVALLO Biologics License Application.
The filings also report financial results and liquidity updates, commercialization and milestone arrangements, amendments to royalty-related purchase and sale agreements, warrant issuance terms, Nasdaq continued-listing compliance notices, and proxy matters such as board elections, executive compensation, equity awards, and shareholder voting proposals.
Redmile Group and related entities updated their ownership disclosure for Atara Biotherapeutics. They report beneficial ownership of 950,994 shares of common stock, representing 9.9% of the class, including shares issuable from pre-funded warrants subject to a 9.99% Beneficial Ownership Limitation.
The filing explains that this increase in deemed beneficial ownership results from a higher number of Atara shares outstanding, which raised the maximum shares issuable upon warrant exercise. Redmile-managed funds directly hold 441,701 common shares and 3,412,843 pre-funded warrants, of which 509,293 shares are currently counted toward beneficial ownership under the limitation.
Atara Biotherapeutics reports a reported 8.56% ownership position held by Adage Capital Management and affiliated individuals.
Adage Capital Management, L.P., together with Robert Atchinson and Phillip Gross, states shared dispositive and voting power over 700,000 shares of Common Stock. The filing calculates the percentage using 8,178,114 shares outstanding as of March 10, 2026. The statement is a joint Schedule 13G disclosure of beneficial ownership and identifies the Reporting Persons and their business addresses.
Atara Biotherapeutics amended its sales-agreement prospectus to confirm it may continue at-the-market sales up to an aggregate offering price of $79,269,007 under the existing Sales Agreement with TD Securities (USA) LLC. This supplement, dated May 12, 2026, relies on a staff interpretation addressing Form S-3 eligibility after a Section 10(a)(3) update.
The supplement states the company may offer and sell shares of Common Stock from time to time through the named sales agent, and that the full amount remaining under the Sales Agreement is available despite a change in the Form S-3 eligibility criterion referenced in General Instruction I.B.1 because the company qualifies under General Instruction I.B.6.
Atara Biotherapeutics, Inc. reported Q1 2026 commercialization revenue of $516,000, sharply lower than $98.1 million a year earlier, when large milestone payments were recognized. The company posted a net loss of $4.1 million, compared with net income of $38.0 million in Q1 2025.
Total assets were $20.0 million and cash and cash equivalents were $8.4 million as of March 31, 2026. Total liabilities were $57.3 million, including $41.5 million related to the sale of future Ebvallo revenues, resulting in a stockholders’ deficit of $37.3 million.
The company states that existing cash and investments will not fund planned operations for 12 months after issuance of these financial statements and concludes that substantial doubt exists about its ability to continue as a going concern. Management plans to seek additional capital, potentially through equity offerings, debt, its ATM program, and strategic transactions, while continuing to rely on Pierre Fabre for global development, manufacturing and commercialization of tab-cel/Ebvallo. Outstanding common shares were 9,010,172 as of May 8, 2026.
Atara Biotherapeutics reported first quarter 2026 results showing a sharp normalization of revenue after a one-time 2025 event and a return to modest losses. Commercialization revenue was $0.5 million, compared with $98.1 million a year earlier, when revenue was accelerated from transferring tab-cel manufacturing to Pierre Fabre.
The company posted a net loss of $4.1 million, or ($0.29) per share, versus net income of $38.0 million in the prior-year period, as operating expenses fell significantly. Research and development expenses dropped to $0.2 million and general and administrative expenses to $3.6 million, reflecting 2025 cost-reduction initiatives.
Cash, cash equivalents and short-term investments were $8.4 million as of March 31, 2026. Atara expects this balance, together with $4.8 million of at-the-market offering proceeds received after quarter end and operating efficiencies, to fund planned operations into mid-2027, despite a capital structure that includes a substantial liability related to the sale of future revenues.
Atara Biotherapeutics’ largest Panacea-affiliated holder updated its ownership report after a significant share sale. Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P. together now report beneficial ownership of 1,318,894 shares of Atara common stock, representing 16.1% of the company’s outstanding shares as of March 10, 2026.
On May 7, 2026, Panacea Venture Healthcare Fund II, L.P. sold 313,446 shares in open market transactions at a weighted average price of $10.0975 per share. James Huang, through Panacea Innovation Limited and related general partners, may be deemed to share beneficial ownership of these holdings but disclaims such beneficial ownership.
Atara Biotherapeutics, Inc. reported an insider filing showing that investment entities associated with Panacea Innovation executed an open-market sale of 313,446 shares of common stock at a weighted average price of $10.0975 per share, with individual trades between $10.00 and $10.50. The shares sold were held by Panacea Venture Healthcare Fund II, L.P. Following the sale, entities associated with Panacea report indirect holdings of 1,011,000 shares in one position and 307,894 shares in another. James Huang and Panacea Innovation Limited may be deemed to share beneficial ownership of these fund holdings, but each expressly disclaims beneficial ownership.
EcoR1 Capital, LLC, a ten percent owner of Atara Biotherapeutics, reported an indirect open-market purchase of 507,407 shares of Common Stock at a weighted average price of $9.35 per share. The shares were bought by funds it advises, which now hold 1,552,000 shares in total.
EcoR1 Capital, LLC filed an initial Form 3 reporting its status as a more than ten percent owner of Atara Biotherapeutics, Inc. common stock. The filing shows indirect beneficial ownership of 1,044,593 shares, with EcoR1-related Qualified Fund holding 970,829 shares for the benefit of its investors.
Atara Biotherapeutics received a Schedule 13G reporting that Point72-affiliated entities beneficially own 526,682 shares of Common Stock, representing 6.2% of the class as of May 7, 2026. The filing states Point72 Asset Management, Point72 Capital Advisors Inc., and Steven A. Cohen share voting and dispositive power over these shares through Point72 Associates under a joint filing agreement. The reporting persons own no shares directly and the disclosure notes Point72 Associates has the right to receive dividends or sale proceeds for the reported position.