{"schema_version":"secwatch.filing_event.v1","accession":"0001193125-24-284167","form_type":"8-K","ticker":"ATRA","cik":"0001604464","company_name":"Atara Biotherapeutics, Inc.","filed_at":"2024-12-23T23:59:59+00:00","discovered_at":"2026-05-14T18:03:08.945480+00:00","generated_at":"2026-05-28T23:37:08.145063+00:00","sec_items":["5.03","9.01"],"event_type":"other","sentiment":"neutral","materiality_score":0.3,"calibrated_materiality_score":0.3,"confidence":"high","headline":"Atara Biotherapeutics adopts Third Amended and Restated Bylaws with governance changes","bullets":["Board approved revised bylaws effective Dec 20, 2024; includes rights to postpone/cancel special stockholder meetings.","Grants Board exclusive use of white proxy card; enhances chair's authority over meeting conduct.","Tightens disclosure and procedural requirements for stockholder proposals and director nominations.","Adds severability clause and other administrative updates."],"urls":{"canonical":"https://secwatch.observer/filing/0001193125-24-284167","json":"https://secwatch.observer/filing/0001193125-24-284167.json","markdown":"https://secwatch.observer/filing/0001193125-24-284167.md","text":"https://secwatch.observer/filing/0001193125-24-284167.txt","edgar_index":"https://www.sec.gov/Archives/edgar/data/1604464/000119312524284167/0001193125-24-284167-index.htm","edgar_primary_document":"https://www.sec.gov/Archives/edgar/data/1604464/000119312524284167/d480921d8k.htm"},"model":{"generated_by":"deepseek-v4-flash:cloud@v2","generated_at":"2026-05-28T23:37:08.145063+00:00"},"review":{"review_status":"machine_generated","human_reviewed":false,"corrected":false,"correction_note":null,"correction_timestamp":null,"superseded_by":null,"related_filings":[]},"source_grounded_claims":[{"claim_id":"b186da29fcaff62402e4c90718b0c631d37ccf6c","claim":"Atara Biotherapeutics, Inc.: Board approved Third Amended and Restated Bylaws with principal revisions including additional rights to postpone/reschedule special meetings, exclusive use of white proxy card for the Board, meeting conduct rules, stockholder proposal disclosure and procedural requirements, director eligibility req (effective 2024-12-20).","evidence_excerpt":"On December 20, 2024, the Board of Directors (the “ Board ”) of Atara Biotherapeutics, Inc., a Delaware corporation (the “ Company ”), approved the amendment and restatement of the Bylaws of the Company (the “ Third Amended and Restated Bylaws ”).","evidence_source":"SEC 8-K Item 5.03/5.05/5.06","evidence_url":"https://www.sec.gov/Archives/edgar/data/1604464/000119312524284167/0001193125-24-284167-index.htm","confidence":0.9,"family_label":"Governance Changes","details":[{"label":"Change","value":"bylaw amendment"},{"label":"Effective","value":"2024-12-20"}],"fact_type":"governance_change"}],"license":"Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer"}