{"schema_version":"secwatch.filing_event.v1","accession":"0001193125-25-068789","form_type":"8-K","ticker":"ATRA","cik":"0001604464","company_name":"Atara Biotherapeutics, Inc.","filed_at":"2025-03-31T23:59:59+00:00","discovered_at":"2026-05-14T18:03:04.165968+00:00","generated_at":"2026-05-24T01:52:00.966205+00:00","sec_items":["5.02"],"event_type":"leadership","sentiment":"neutral","materiality_score":0.6,"calibrated_materiality_score":0.6,"confidence":"high","headline":"Atara CFO/COO Eric Hyllengren to depart March 31; Yanina Grant-Huerta named CAO","bullets":["CFO/COO Eric Hyllengren's employment ends March 31, 2025; he will provide consulting through July 31 at an hourly rate.","Hyllengren receives severance including 2024 bonus; he relinquishes all vested and unvested stock option awards.","Yanina Grant-Huerta appointed Chief Accounting Officer and principal accounting officer effective March 31; she was VP of FP&A since March 2023.","Grant-Huerta previously spent 13 years at Amgen; no family relationships or related-party transactions disclosed."],"urls":{"canonical":"https://secwatch.observer/filing/0001193125-25-068789","json":"https://secwatch.observer/filing/0001193125-25-068789.json","markdown":"https://secwatch.observer/filing/0001193125-25-068789.md","text":"https://secwatch.observer/filing/0001193125-25-068789.txt","edgar_index":"https://www.sec.gov/Archives/edgar/data/1604464/000119312525068789/0001193125-25-068789-index.htm","edgar_primary_document":"https://www.sec.gov/Archives/edgar/data/1604464/000119312525068789/d905889d8k.htm"},"model":{"generated_by":"deepseek-v4-flash:cloud@v2","generated_at":"2026-05-24T01:52:00.966205+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":"01f1fe4d82","claim":"Eric Hyllengren departed as Chief Financial Officer and Chief Operating Officer at Atara Biotherapeutics, Inc..","evidence_excerpt":"On March 25, 2025, it was agreed that the employment of Eric Hyllengren, the Chief Financial Officer and Chief Operating Officer of Atara Biotherapeutics, Inc. (the “ Company ”), would end effective March 31, 2025.","evidence_source":"SEC 8-K Item 5.02","evidence_url":"https://www.sec.gov/Archives/edgar/data/1604464/000119312525068789/0001193125-25-068789-index.htm","confidence":0.95,"family_label":"Executive change","details":[{"label":"Action","value":"ended"},{"label":"Role","value":"Chief Financial Officer and Chief Operating Officer"}],"fact_type":"executive_change"},{"claim_id":"f86e471420","claim":"Yanina Grant-Huerta was appointed as Chief Accounting Officer at Atara Biotherapeutics, Inc..","evidence_excerpt":"On March 31, 2025, the Company appointed Yanina Grant-Huerta as the Company’s Chief Accounting Officer and principal accounting officer, effective March 31, 2025.","evidence_source":"SEC 8-K Item 5.02","evidence_url":"https://www.sec.gov/Archives/edgar/data/1604464/000119312525068789/0001193125-25-068789-index.htm","confidence":0.95,"family_label":"Executive change","details":[{"label":"Action","value":"appointed"},{"label":"Role","value":"Chief Accounting Officer"}],"fact_type":"executive_change"}],"license":"Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer"}