Every 424B that Atara Biotherape (ATRA) has filed with the SEC in the last 12 months is listed below, newest first, and each one links through to the document itself with the summary and the scores our analysis gives it.
A 424B covers the supplement that carries the terms of a priced offering, so if you follow ATRA and want that one kind of document rather than the whole filing history, this is the page to keep. The company's other filings, of every form, are on the full ATRA filings page.
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 is registering for resale up to 400,000 shares of its common stock by HCR Molag Fund, L.P.
The shares are issuable upon exercise of a warrant that Atara issued under an amendment dated February 20, 2026 and are being registered to satisfy a covenant in that Warrant. The company will receive no proceeds from sales by the selling stockholder; Atara may receive proceeds only if the Warrant is exercised. The filing states 8,178,114 shares outstanding as of March 10, 2026 and a Beneficial Ownership Limitation that prevents exercise to the extent it would cause ownership above 4.99% (subject to increase up to 19.99% with notice and a 61‑day delay). Atara’s common stock is listed on Nasdaq and the last reported sale price in the prospectus was $6.50.
Atara Biotherapeutics registers the offer and sale of up to $11,135,981 of its common stock under a sales agreement with TD Securities (USA) LLC.
The Supplement states the offering is being made pursuant to General Instruction I.B.6 of Form S-3 and is limited by the companys aggregate market value of non-affiliate float of $33,407,943.90 (based on 4,841,731 shares held by non-affiliates as of March 10, 2026 at a price of $6.90 per share). The filing notes the last reported sales price was $6.50 on March 13, 2026.