{"transactions":[{"id":4934,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":10254,"kind":"person","name":"Cherry Brian N","position":1,"cik":"0001290922","reported_name":"Cherry Brian N","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-09-04T22:20:04.000Z","date":"2026-09-04","kind":"purchase","planned":false,"acquired":true,"shares":104166,"price":9.6,"value":999993.6,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents shares purchased by the Reporting Person from the Issuer, through its sales agent, pursuant to that certain Sales Agreement, dated November 1, 2023, by and between the Issuer and TD Securities (USA) LLC."}],"balance_after":166486,"source":{"system":"sec-edgar","filing":"0000905148-26-004085","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1604464/000090514826004085/form4.xml","form_type":"4"}},{"id":674641,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":19394,"kind":"person","name":"Nguyen AnhCo","position":1,"cik":"0001977970","reported_name":"Nguyen AnhCo","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-08-26T23:45:25.000Z","date":"2026-08-17","kind":"sale","planned":false,"acquired":false,"shares":5062,"price":8.0764,"value":40882.7368,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Shares sold automatically to satisfy tax withholding obligations in connection with the vesting of previously granted restricted stock units, pursuant to a sale-to-cover provision in the award agreement."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The sale price of the reporting person's shares represents the weighted average price of all shares sold by a broker on August 17, 2026, on behalf of a group of employees of the Issuer to satisfy the payment of withholding tax liability of such employees."}],"balance_after":132775,"source":{"system":"sec-edgar","filing":"0000905148-26-003960","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1604464/000090514826003960/form4.xml","form_type":"4"}},{"id":703475,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":25414,"kind":"organization","name":"Redmile Group, LLC","position":1,"cik":"0001425738","reported_name":"Redmile Group, LLC","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}},{"id":25415,"kind":"person","name":"Green Jeremy","position":2,"cik":"0001650527","reported_name":"Green Jeremy","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Pre-Funded Warrants to Purchase Common Stock","published_at":"2026-07-25T01:00:10.000Z","date":"2026-07-22","kind":"exercise","planned":false,"acquired":false,"shares":55387,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"The Pre-Funded Warrants are exercisable at any time on or after the original issuance on December 11, 2020 until the seven-year anniversary of the original issuance date, at an exercise price equal to $0.0025 per share, subject to a 9.99% beneficial ownership blocker."},{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F8","text":"The previous report on Form 3 inadvertently indicated that all of the Pre-Funded Warrants beneficially owned by the Reporting Persons have an exercise price of $0.0001 per share and no expiration date. Footnotes (1), (2), (3), (6) and (7) and the related disclosures correct the Form 3 with respect to the terms of the Pre-Funded Warrants beneficially owned by the Reporting Persons."},{"field":"kind","element":"transactionCoding","label":"F5","text":"On July 22, 2026, the Reporting Persons exercised the reported Pre-Funded Warrants through a \"cashless exercise\" resulting in the Issuer withholding 60 shares of Common Stock to pay the exercise price and issuing the remaining 195,151 shares of Common Stock to the applicable Funds. The number of shares withheld to pay the aggregate exercise price for the cashless exercise of the Pre-Funded Warrants was based on the closing sale price per share of the Common Stock on the trading date immediately prior to the exercise date, per the terms of the Pre-Funded Warrants."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The Pre-Funded Warrants are exercisable at any time on or after the original issuance on December 11, 2020 until the seven-year anniversary of the original issuance date, at an exercise price equal to $0.0025 per share, subject to a 9.99% beneficial ownership blocker."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F8","text":"The previous report on Form 3 inadvertently indicated that all of the Pre-Funded Warrants beneficially owned by the Reporting Persons have an exercise price of $0.0001 per share and no expiration date. Footnotes (1), (2), (3), (6) and (7) and the related disclosures correct the Form 3 with respect to the terms of the Pre-Funded Warrants beneficially owned by the Reporting Persons."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F3","text":"The Pre-Funded Warrants are exercisable at any time on or after the original issuance on December 11, 2020 until the seven-year anniversary of the original issuance date, at an exercise price equal to $0.0025 per share, subject to a 9.99% beneficial ownership blocker."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F8","text":"The previous report on Form 3 inadvertently indicated that all of the Pre-Funded Warrants beneficially owned by the Reporting Persons have an exercise price of $0.0001 per share and no expiration date. Footnotes (1), (2), (3), (6) and (7) and the related disclosures correct the Form 3 with respect to the terms of the Pre-Funded Warrants beneficially owned by the Reporting Persons."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F4","text":"The reported securities are directly owned by certain private funds managed by Redmile Group, LLC (collectively, the \"Funds\") and may be deemed beneficially owned by Redmile Group, LLC (\"Redmile\") as investment manager of the Funds. The reported securities may also be deemed beneficially owned by Jeremy Green as the principal of Redmile. Each of Redmile and Mr. Green (the \"Reporting Persons\") disclaims beneficial ownership of the reported securities except to the extent of their pecuniary interest therein, if any. This report shall not be deemed an admission that such Reporting Persons are the beneficial owners of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."}],"balance_after":0,"derivative":{"exercise_price":0.0025,"underlying":"Common Stock","underlying_shares":55387},"source":{"system":"sec-edgar","filing":"0001104659-26-086733","document":"tm2621190-2_4seq1.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1425738/000110465926086733/tm2621190-2_4seq1.xml","form_type":"4"}},{"id":703474,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":25414,"kind":"organization","name":"Redmile Group, LLC","position":1,"cik":"0001425738","reported_name":"Redmile Group, LLC","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}},{"id":25415,"kind":"person","name":"Green Jeremy","position":2,"cik":"0001650527","reported_name":"Green Jeremy","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Pre-Funded Warrants to Purchase Common Stock","published_at":"2026-07-25T01:00:10.000Z","date":"2026-07-22","kind":"exercise","planned":false,"acquired":false,"shares":38735,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"The Pre-Funded Warrants are exercisable at any time on or after the original issuance on May 29, 2020 until the seven-year anniversary of the original issuance date, at an exercise price equal to $0.0025 per share, subject to a 9.99% beneficial ownership blocker."},{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F8","text":"The previous report on Form 3 inadvertently indicated that all of the Pre-Funded Warrants beneficially owned by the Reporting Persons have an exercise price of $0.0001 per share and no expiration date. Footnotes (1), (2), (3), (6) and (7) and the related disclosures correct the Form 3 with respect to the terms of the Pre-Funded Warrants beneficially owned by the Reporting Persons."},{"field":"kind","element":"transactionCoding","label":"F5","text":"On July 22, 2026, the Reporting Persons exercised the reported Pre-Funded Warrants through a \"cashless exercise\" resulting in the Issuer withholding 60 shares of Common Stock to pay the exercise price and issuing the remaining 195,151 shares of Common Stock to the applicable Funds. The number of shares withheld to pay the aggregate exercise price for the cashless exercise of the Pre-Funded Warrants was based on the closing sale price per share of the Common Stock on the trading date immediately prior to the exercise date, per the terms of the Pre-Funded Warrants."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The Pre-Funded Warrants are exercisable at any time on or after the original issuance on May 29, 2020 until the seven-year anniversary of the original issuance date, at an exercise price equal to $0.0025 per share, subject to a 9.99% beneficial ownership blocker."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F8","text":"The previous report on Form 3 inadvertently indicated that all of the Pre-Funded Warrants beneficially owned by the Reporting Persons have an exercise price of $0.0001 per share and no expiration date. Footnotes (1), (2), (3), (6) and (7) and the related disclosures correct the Form 3 with respect to the terms of the Pre-Funded Warrants beneficially owned by the Reporting Persons."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"The Pre-Funded Warrants are exercisable at any time on or after the original issuance on May 29, 2020 until the seven-year anniversary of the original issuance date, at an exercise price equal to $0.0025 per share, subject to a 9.99% beneficial ownership blocker."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F8","text":"The previous report on Form 3 inadvertently indicated that all of the Pre-Funded Warrants beneficially owned by the Reporting Persons have an exercise price of $0.0001 per share and no expiration date. Footnotes (1), (2), (3), (6) and (7) and the related disclosures correct the Form 3 with respect to the terms of the Pre-Funded Warrants beneficially owned by the Reporting Persons."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F4","text":"The reported securities are directly owned by certain private funds managed by Redmile Group, LLC (collectively, the \"Funds\") and may be deemed beneficially owned by Redmile Group, LLC (\"Redmile\") as investment manager of the Funds. The reported securities may also be deemed beneficially owned by Jeremy Green as the principal of Redmile. Each of Redmile and Mr. Green (the \"Reporting Persons\") disclaims beneficial ownership of the reported securities except to the extent of their pecuniary interest therein, if any. This report shall not be deemed an admission that such Reporting Persons are the beneficial owners of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."}],"balance_after":0,"derivative":{"exercise_price":0.0025,"underlying":"Common Stock","underlying_shares":38735},"source":{"system":"sec-edgar","filing":"0001104659-26-086733","document":"tm2621190-2_4seq1.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1425738/000110465926086733/tm2621190-2_4seq1.xml","form_type":"4"}},{"id":703473,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":25414,"kind":"organization","name":"Redmile Group, LLC","position":1,"cik":"0001425738","reported_name":"Redmile Group, LLC","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}},{"id":25415,"kind":"person","name":"Green Jeremy","position":2,"cik":"0001650527","reported_name":"Green Jeremy","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Pre-Funded Warrants to Purchase Common Stock","published_at":"2026-07-25T01:00:10.000Z","date":"2026-07-22","kind":"exercise","planned":false,"acquired":false,"shares":101089,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"The Pre-Funded Warrants are exercisable at any time on or after the original issuance on July 23, 2019 until the seven-year anniversary of the original issuance date, at an exercise price equal to $0.0025 per share, subject to a 9.99% beneficial ownership blocker."},{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F8","text":"The previous report on Form 3 inadvertently indicated that all of the Pre-Funded Warrants beneficially owned by the Reporting Persons have an exercise price of $0.0001 per share and no expiration date. Footnotes (1), (2), (3), (6) and (7) and the related disclosures correct the Form 3 with respect to the terms of the Pre-Funded Warrants beneficially owned by the Reporting Persons."},{"field":"kind","element":"transactionCoding","label":"F5","text":"On July 22, 2026, the Reporting Persons exercised the reported Pre-Funded Warrants through a \"cashless exercise\" resulting in the Issuer withholding 60 shares of Common Stock to pay the exercise price and issuing the remaining 195,151 shares of Common Stock to the applicable Funds. The number of shares withheld to pay the aggregate exercise price for the cashless exercise of the Pre-Funded Warrants was based on the closing sale price per share of the Common Stock on the trading date immediately prior to the exercise date, per the terms of the Pre-Funded Warrants."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"The Pre-Funded Warrants are exercisable at any time on or after the original issuance on July 23, 2019 until the seven-year anniversary of the original issuance date, at an exercise price equal to $0.0025 per share, subject to a 9.99% beneficial ownership blocker."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F8","text":"The previous report on Form 3 inadvertently indicated that all of the Pre-Funded Warrants beneficially owned by the Reporting Persons have an exercise price of $0.0001 per share and no expiration date. Footnotes (1), (2), (3), (6) and (7) and the related disclosures correct the Form 3 with respect to the terms of the Pre-Funded Warrants beneficially owned by the Reporting Persons."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F1","text":"The Pre-Funded Warrants are exercisable at any time on or after the original issuance on July 23, 2019 until the seven-year anniversary of the original issuance date, at an exercise price equal to $0.0025 per share, subject to a 9.99% beneficial ownership blocker."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F8","text":"The previous report on Form 3 inadvertently indicated that all of the Pre-Funded Warrants beneficially owned by the Reporting Persons have an exercise price of $0.0001 per share and no expiration date. Footnotes (1), (2), (3), (6) and (7) and the related disclosures correct the Form 3 with respect to the terms of the Pre-Funded Warrants beneficially owned by the Reporting Persons."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F4","text":"The reported securities are directly owned by certain private funds managed by Redmile Group, LLC (collectively, the \"Funds\") and may be deemed beneficially owned by Redmile Group, LLC (\"Redmile\") as investment manager of the Funds. The reported securities may also be deemed beneficially owned by Jeremy Green as the principal of Redmile. Each of Redmile and Mr. Green (the \"Reporting Persons\") disclaims beneficial ownership of the reported securities except to the extent of their pecuniary interest therein, if any. This report shall not be deemed an admission that such Reporting Persons are the beneficial owners of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."}],"balance_after":0,"derivative":{"exercise_price":0.0025,"underlying":"Common Stock","underlying_shares":101089},"source":{"system":"sec-edgar","filing":"0001104659-26-086733","document":"tm2621190-2_4seq1.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1425738/000110465926086733/tm2621190-2_4seq1.xml","form_type":"4"}},{"id":703472,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":25414,"kind":"organization","name":"Redmile Group, LLC","position":1,"cik":"0001425738","reported_name":"Redmile Group, LLC","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}},{"id":25415,"kind":"person","name":"Green Jeremy","position":2,"cik":"0001650527","reported_name":"Green Jeremy","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-07-25T01:00:10.000Z","date":"2026-07-22","kind":"tax_withholding","planned":false,"acquired":false,"shares":60,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F5","text":"On July 22, 2026, the Reporting Persons exercised the reported Pre-Funded Warrants through a \"cashless exercise\" resulting in the Issuer withholding 60 shares of Common Stock to pay the exercise price and issuing the remaining 195,151 shares of Common Stock to the applicable Funds. The number of shares withheld to pay the aggregate exercise price for the cashless exercise of the Pre-Funded Warrants was based on the closing sale price per share of the Common Stock on the trading date immediately prior to the exercise date, per the terms of the Pre-Funded Warrants."},{"field":"price","element":"transactionPricePerShare","label":"F5","text":"On July 22, 2026, the Reporting Persons exercised the reported Pre-Funded Warrants through a \"cashless exercise\" resulting in the Issuer withholding 60 shares of Common Stock to pay the exercise price and issuing the remaining 195,151 shares of Common Stock to the applicable Funds. The number of shares withheld to pay the aggregate exercise price for the cashless exercise of the Pre-Funded Warrants was based on the closing sale price per share of the Common Stock on the trading date immediately prior to the exercise date, per the terms of the Pre-Funded Warrants."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F4","text":"The reported securities are directly owned by certain private funds managed by Redmile Group, LLC (collectively, the \"Funds\") and may be deemed beneficially owned by Redmile Group, LLC (\"Redmile\") as investment manager of the Funds. The reported securities may also be deemed beneficially owned by Jeremy Green as the principal of Redmile. Each of Redmile and Mr. Green (the \"Reporting Persons\") disclaims beneficial ownership of the reported securities except to the extent of their pecuniary interest therein, if any. This report shall not be deemed an admission that such Reporting Persons are the beneficial owners of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."}],"balance_after":636852,"source":{"system":"sec-edgar","filing":"0001104659-26-086733","document":"tm2621190-2_4seq1.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1425738/000110465926086733/tm2621190-2_4seq1.xml","form_type":"4"}},{"id":703471,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":25414,"kind":"organization","name":"Redmile Group, LLC","position":1,"cik":"0001425738","reported_name":"Redmile Group, LLC","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}},{"id":25415,"kind":"person","name":"Green Jeremy","position":2,"cik":"0001650527","reported_name":"Green Jeremy","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-07-25T01:00:10.000Z","date":"2026-07-22","kind":"exercise","planned":false,"acquired":true,"shares":195211,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F5","text":"On July 22, 2026, the Reporting Persons exercised the reported Pre-Funded Warrants through a \"cashless exercise\" resulting in the Issuer withholding 60 shares of Common Stock to pay the exercise price and issuing the remaining 195,151 shares of Common Stock to the applicable Funds. The number of shares withheld to pay the aggregate exercise price for the cashless exercise of the Pre-Funded Warrants was based on the closing sale price per share of the Common Stock on the trading date immediately prior to the exercise date, per the terms of the Pre-Funded Warrants."},{"field":"price","element":"transactionPricePerShare","label":"F5","text":"On July 22, 2026, the Reporting Persons exercised the reported Pre-Funded Warrants through a \"cashless exercise\" resulting in the Issuer withholding 60 shares of Common Stock to pay the exercise price and issuing the remaining 195,151 shares of Common Stock to the applicable Funds. The number of shares withheld to pay the aggregate exercise price for the cashless exercise of the Pre-Funded Warrants was based on the closing sale price per share of the Common Stock on the trading date immediately prior to the exercise date, per the terms of the Pre-Funded Warrants."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F4","text":"The reported securities are directly owned by certain private funds managed by Redmile Group, LLC (collectively, the \"Funds\") and may be deemed beneficially owned by Redmile Group, LLC (\"Redmile\") as investment manager of the Funds. The reported securities may also be deemed beneficially owned by Jeremy Green as the principal of Redmile. Each of Redmile and Mr. Green (the \"Reporting Persons\") disclaims beneficial ownership of the reported securities except to the extent of their pecuniary interest therein, if any. This report shall not be deemed an admission that such Reporting Persons are the beneficial owners of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose."}],"balance_after":636912,"source":{"system":"sec-edgar","filing":"0001104659-26-086733","document":"tm2621190-2_4seq1.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1425738/000110465926086733/tm2621190-2_4seq1.xml","form_type":"4"}},{"id":737651,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":10254,"kind":"person","name":"Cherry Brian N","position":1,"cik":"0001290922","reported_name":"Cherry Brian N","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-06-15T22:51:31.000Z","date":"2026-06-11","kind":"grant","planned":false,"acquired":true,"shares":24000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"These restricted stock units shall vest as to 1/3 of the shares on the first, second and third anniversaries of June 11, 2026, subject to the Reporting Person's continuous service."}],"balance_after":62320,"source":{"system":"sec-edgar","filing":"0000905148-26-002951","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1290922/000090514826002951/form4.xml","form_type":"4"}},{"id":741408,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":39201,"kind":"person","name":"HEIDEN WILLIAM K","position":1,"cik":"0001214939","reported_name":"HEIDEN WILLIAM K","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-06-11T20:37:50.000Z","date":"2026-06-09","kind":"grant","planned":false,"acquired":true,"shares":12000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"These restricted stock units shall vest on the earlier of June 9, 2027 or the date of the next annual meeting of stockholders, subject to the Reporting Person's continuous service."}],"balance_after":34188,"source":{"system":"sec-edgar","filing":"0000905148-26-002921","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1214939/000090514826002921/form4.xml","form_type":"4"}},{"id":741275,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":17933,"kind":"person","name":"Fust Matthew K","position":1,"cik":"0001397266","reported_name":"Fust Matthew K","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-06-11T20:36:58.000Z","date":"2026-06-09","kind":"grant","planned":false,"acquired":true,"shares":12000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"These restricted stock units shall vest on the earlier of June 9, 2027 or the date of the next annual meeting of stockholders, subject to the Reporting Person's continuous service."}],"balance_after":30188,"source":{"system":"sec-edgar","filing":"0000905148-26-002920","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1397266/000090514826002920/form4.xml","form_type":"4"}},{"id":741993,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":19139,"kind":"person","name":"Ciongoli Gregory Austin","position":1,"cik":"0002023732","reported_name":"Ciongoli Gregory Austin","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":true,"other_text":"See Remarks"}}],"security":"Common Stock","published_at":"2026-06-11T20:36:04.000Z","date":"2026-06-09","kind":"grant","planned":false,"acquired":true,"shares":12000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"These restricted stock units shall vest on the earlier of June 9, 2027 or the date of the next annual meeting of stockholders, subject to the Reporting Person's continuous service."}],"balance_after":12000,"source":{"system":"sec-edgar","filing":"0000905148-26-002919","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2023732/000090514826002919/form4.xml","form_type":"4"}},{"id":769589,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":19394,"kind":"person","name":"Nguyen AnhCo","position":1,"cik":"0001977970","reported_name":"Nguyen AnhCo","relationship":{"director":true,"officer":true,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-05-20T21:24:39.000Z","date":"2026-05-18","kind":"sale","planned":false,"acquired":false,"shares":5241,"price":9.1289,"value":47844.5649,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Shares sold automatically to satisfy tax withholding obligations in connection with the vesting of previously granted restricted stock units, pursuant to a sale-to-cover provision in the award agreement."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Represents the weighted average price. The shares were sold in multiple transactions at prices ranging from $9.12 to $9.40, inclusive. The Reporting Person undertakes to provide to the Issuer, any securityholder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above."}],"balance_after":137837,"source":{"system":"sec-edgar","filing":"0000905148-26-002571","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1604464/000090514826002571/form4.xml","form_type":"4"}},{"id":770308,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":22991,"kind":"person","name":"Grant-Huerta Yanina","position":1,"cik":"0002064348","reported_name":"Grant-Huerta Yanina","relationship":{"officer":true,"officer_title":"Chief Accounting Officer"}}],"security":"Common Stock","published_at":"2026-05-20T21:24:23.000Z","date":"2026-05-18","kind":"sale","planned":false,"acquired":false,"shares":2414,"price":9.1286,"value":22036.4404,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Shares sold automatically to satisfy tax withholding obligations in connection with the vesting of previously granted restricted stock units, pursuant to a sale-to-cover provision in the award agreement."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Represents the weighted average price. The shares were sold in multiple transactions at prices ranging from $9.12 to $9.40, inclusive. The Reporting Person undertakes to provide to the Issuer, any securityholder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above."}],"balance_after":49636,"source":{"system":"sec-edgar","filing":"0000905148-26-002570","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2064348/000090514826002570/form4.xml","form_type":"4"}},{"id":784381,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":48282,"kind":"organization","name":"Panacea Innovation Ltd","position":1,"cik":"0002010692","reported_name":"Panacea Innovation Ltd","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":42283,"kind":"person","name":"Huang James","position":2,"cik":"0001573160","reported_name":"Huang James","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock","published_at":"2026-05-11T22:45:04.000Z","date":"2026-05-07","kind":"sale","planned":false,"acquired":false,"shares":313446,"price":10.0975,"value":3165020.985,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $10.00 to $10.50, inclusive. The Reporting Person undertake to provide to the Issuer, any securityholder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Represents securities held by Panacea Venture Healthcare Fund II, L.P."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"James Huang is the sole owner of Panacea Innovation Limited, which is the sole owner of Panacea Venture Healthcare Fund II GP Company, Ltd. (\"Fund II GP\") and Panacea Opportunity Fund I GP Company, Ltd. (\"Opportunity Fund GP\"), which are the general partners of Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P. As a result, each of the Reporting Persons may be deemed to share beneficial ownership of the securities held of record by Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P., but each disclaims such beneficial ownership."}],"balance_after":1011000,"source":{"system":"sec-edgar","filing":"0001193125-26-217380","document":"ownership.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1573160/000119312526217380/ownership.xml","form_type":"4"}},{"id":784375,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":48279,"kind":"organization","name":"EcoR1 Capital, LLC","position":1,"cik":"0001587114","reported_name":"EcoR1 Capital, LLC","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock","published_at":"2026-05-11T21:34:20.000Z","date":"2026-05-07","kind":"purchase","planned":false,"acquired":true,"shares":507407,"price":9.35,"value":4744255.45,"ownership":{"direct":false,"nature":"See Note"},"footnotes":[{"field":"shares","element":"transactionShares","label":"F2","text":"Qualified Fund purchased 474,780 of the shares puchased in this transaction."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $8.85 to $9.39 inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in this footnote."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F4","text":"After this transaction, Qualified Fund held 1,445,609 shares of the Issuer's Common Stock."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"The reporting persons are EcoR1 Capital, LLC (\"EcoR1\"), Oleg Nodelman and EcoR1 Capital Fund Qualified, L.P. (\"Qualified Fund\"). EcoR1 is the general partner and investment adviser of private funds, including Qualified Fund (the \"Funds\"). Mr. Nodelman is the manager and controller owner of EcoR1. EcoR1 is filing this Form 4 for itself, Mr. Nodelman and Qualified Fund. The reporting persons are filing this Form 4 jointly, but not as a group, and each expressly disclaims membership in a group within the meaning of Rule 13d-5(b) under the Securities Exchange Act of 1934. The Funds hold these securities directly for the benefit of their investors. EcoR1 may be deemed to indirectly beneficially own them as the investment adviser to the Funds. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1. The reporting persons disclaim beneficial ownership of the securities except to the extent of their respective pecuniary interests therein."}],"balance_after":1552000,"source":{"system":"sec-edgar","filing":"0000935836-26-000239","document":"ownership.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1587114/000093583626000239/ownership.xml","form_type":"4"}},{"id":833171,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":48282,"kind":"organization","name":"Panacea Innovation Ltd","position":1,"cik":"0002010692","reported_name":"Panacea Innovation Ltd","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":42283,"kind":"person","name":"Huang James","position":2,"cik":"0001573160","reported_name":"Huang James","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Warrants","published_at":"2026-03-19T20:30:10.000Z","date":"2026-03-17","kind":"exercise","planned":false,"acquired":false,"shares":259163,"price":6.6099,"value":1713041.5137,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The warrants are immediately exercisable and do not expire. Pursuant to the terms of the warrants, no portion of the warrants held by a holder may be exercised to the extent that, after giving effect to the attempted exercise, such holder, together with such holder's affiliates and any other person whose beneficial ownership of the Issuer's common stock would be aggregated with such holder's for the purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of the outstanding common stock."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The warrants are immediately exercisable and do not expire. Pursuant to the terms of the warrants, no portion of the warrants held by a holder may be exercised to the extent that, after giving effect to the attempted exercise, such holder, together with such holder's affiliates and any other person whose beneficial ownership of the Issuer's common stock would be aggregated with such holder's for the purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of the outstanding common stock."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"Represents securities held by Panacea Opportunity Fund I, L.P."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"James Huang is the sole owner of Panacea Innovation Limited, which is the sole owner of Panacea Venture Healthcare Fund II GP Company, Ltd. (\"Fund II GP\") and Panacea Opportunity Fund I GP Company, Ltd. (\"Opportunity Fund GP\"), which are the general partners of Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P. As a result, each of the Reporting Persons may be deemed to share beneficial ownership of the securities held of record by Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P., but each disclaims such beneficial ownership."}],"balance_after":0,"derivative":{"exercise_price":0.0001,"underlying":"Common Stock","underlying_shares":259163},"source":{"system":"sec-edgar","filing":"0001193125-26-116060","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1573160/000119312526116060/ownership.xml","form_type":"4"}},{"id":833170,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":48282,"kind":"organization","name":"Panacea Innovation Ltd","position":1,"cik":"0002010692","reported_name":"Panacea Innovation Ltd","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":42283,"kind":"person","name":"Huang James","position":2,"cik":"0001573160","reported_name":"Huang James","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock","published_at":"2026-03-19T20:30:10.000Z","date":"2026-03-17","kind":"tax_withholding","planned":false,"acquired":false,"shares":5,"price":5.23,"value":26.15,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"Represents securities held by Panacea Opportunity Fund I, L.P."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"James Huang is the sole owner of Panacea Innovation Limited, which is the sole owner of Panacea Venture Healthcare Fund II GP Company, Ltd. (\"Fund II GP\") and Panacea Opportunity Fund I GP Company, Ltd. (\"Opportunity Fund GP\"), which are the general partners of Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P. As a result, each of the Reporting Persons may be deemed to share beneficial ownership of the securities held of record by Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P., but each disclaims such beneficial ownership."}],"balance_after":307894,"source":{"system":"sec-edgar","filing":"0001193125-26-116060","document":"ownership.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1573160/000119312526116060/ownership.xml","form_type":"4"}},{"id":833169,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":48282,"kind":"organization","name":"Panacea Innovation Ltd","position":1,"cik":"0002010692","reported_name":"Panacea Innovation Ltd","relationship":{"director":false,"officer":false,"ten_percent_owner":true,"other":false}},{"id":42283,"kind":"person","name":"Huang James","position":2,"cik":"0001573160","reported_name":"Huang James","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Common Stock","published_at":"2026-03-19T20:30:10.000Z","date":"2026-03-17","kind":"exercise","planned":false,"acquired":true,"shares":259163,"price":0.0001,"value":25.9163,"ownership":{"direct":false,"nature":"See Footnotes"},"footnotes":[{"field":"ownership.nature","element":"natureOfOwnership","label":"F1","text":"Represents securities held by Panacea Opportunity Fund I, L.P."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"James Huang is the sole owner of Panacea Innovation Limited, which is the sole owner of Panacea Venture Healthcare Fund II GP Company, Ltd. (\"Fund II GP\") and Panacea Opportunity Fund I GP Company, Ltd. (\"Opportunity Fund GP\"), which are the general partners of Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P. As a result, each of the Reporting Persons may be deemed to share beneficial ownership of the securities held of record by Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P., but each disclaims such beneficial ownership."}],"balance_after":307899,"source":{"system":"sec-edgar","filing":"0001193125-26-116060","document":"ownership.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1573160/000119312526116060/ownership.xml","form_type":"4"}},{"id":848202,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":19394,"kind":"person","name":"Nguyen AnhCo","position":1,"cik":"0001977970","reported_name":"Nguyen AnhCo","relationship":{"director":true,"officer":true,"officer_title":"President and CEO"}}],"security":"Common Stock","published_at":"2026-03-11T21:46:05.000Z","date":"2026-03-09","kind":"grant","planned":false,"acquired":true,"shares":81100,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"These restricted stock units (\"RSUs\") vest as to 1/8th of the total number of shares (rounded down to the next whole number of shares) on the second Quarterly Vesting Date (as defined below) following March 9, 2026, and as to 1/8th of the total number of shares (rounded down to the next whole number of shares) on the next seven Quarterly Vesting Dates, such that all of the shares subject to the RSUs shall be vested on the last Quarterly Vesting Date, subject to the reporting person's continuous employment. \"Quarterly Vesting Date\" means March 1, May 15, August 15, and November 15 of each year, provided that if such date falls on a weekend or holiday, the Quarterly Vesting Date shall be the first business day after such date."}],"balance_after":143078,"source":{"system":"sec-edgar","filing":"0000905148-26-001225","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1604464/000090514826001225/form4.xml","form_type":"4"}},{"id":849157,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":22991,"kind":"person","name":"Grant-Huerta Yanina","position":1,"cik":"0002064348","reported_name":"Grant-Huerta Yanina","relationship":{"officer":true,"officer_title":"Chief Accounting Officer"}}],"security":"Common Stock","published_at":"2026-03-11T21:45:38.000Z","date":"2026-03-09","kind":"grant","planned":false,"acquired":true,"shares":20300,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"These restricted stock units (\"RSUs\") vest as to 1/8th of the total number of shares (rounded down to the next whole number of shares) on the second Quarterly Vesting Date (as defined below) following March 9, 2026, and as to 1/8th of the total number of shares (rounded down to the next whole number of shares) on the next seven Quarterly Vesting Dates, such that all of the shares subject to the RSUs shall be vested on the last Quarterly Vesting Date, subject to the reporting person's continuous employment. \"Quarterly Vesting Date\" means March 1, May 15, August 15, and November 15 of each year, provided that if such date falls on a weekend or holiday, the Quarterly Vesting Date shall be the first business day after such date."}],"balance_after":52050,"source":{"system":"sec-edgar","filing":"0000905148-26-001224","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2064348/000090514826001224/form4.xml","form_type":"4"}},{"id":862400,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":22991,"kind":"person","name":"Grant-Huerta Yanina","position":1,"cik":"0002064348","reported_name":"Grant-Huerta Yanina","relationship":{"officer":true,"officer_title":"Chief Accounting Officer"}}],"security":"Common Stock","published_at":"2026-03-04T21:28:21.000Z","date":"2026-03-02","kind":"sale","planned":false,"acquired":false,"shares":100,"price":5.083,"value":508.3,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Shares sold automatically to satisfy tax withholding obligations in connection with the vesting of previously granted restricted stock units, pursuant to a sale-to-cover provision in the award agreement."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The sale price of the reporting person's shares represents the weighted average price of all shares sold by a broker on March 2, 2026 on behalf of a group of employees of the Issuer to satisfy the payment of withholding tax liability of such employees."}],"balance_after":31750,"source":{"system":"sec-edgar","filing":"0000905148-26-001144","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2064348/000090514826001144/form4.xml","form_type":"4"}},{"id":862399,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":22991,"kind":"person","name":"Grant-Huerta Yanina","position":1,"cik":"0002064348","reported_name":"Grant-Huerta 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employees."}],"balance_after":31850,"source":{"system":"sec-edgar","filing":"0000905148-26-001144","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2064348/000090514826001144/form4.xml","form_type":"4"}},{"id":862398,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":22991,"kind":"person","name":"Grant-Huerta Yanina","position":1,"cik":"0002064348","reported_name":"Grant-Huerta Yanina","relationship":{"officer":true,"officer_title":"Chief Accounting Officer"}}],"security":"Common Stock","published_at":"2026-03-04T21:28:21.000Z","date":"2026-03-02","kind":"sale","planned":false,"acquired":false,"shares":1603,"price":5.081,"value":8144.843,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Shares sold automatically to satisfy tax withholding obligations in connection with the vesting of previously granted restricted stock units, pursuant to a sale-to-cover provision in the award agreement."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The sale price of the reporting person's shares represents the weighted average price of all shares sold by a broker on March 2, 2026 on behalf of a group of employees of the Issuer to satisfy the payment of withholding tax liability of such employees."}],"balance_after":32227,"source":{"system":"sec-edgar","filing":"0000905148-26-001144","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2064348/000090514826001144/form4.xml","form_type":"4"}},{"id":862397,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":22991,"kind":"person","name":"Grant-Huerta Yanina","position":1,"cik":"0002064348","reported_name":"Grant-Huerta 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the vesting of previously granted restricted stock units, pursuant to a sale-to-cover provision in the award agreement."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The sale price of the reporting person's shares represents the weighted average price of all shares sold by a broker on March 2, 2026 on behalf of a group of employees of the Issuer to satisfy the payment of withholding tax liability of such employees."}],"balance_after":63420,"source":{"system":"sec-edgar","filing":"0000905148-26-001143","document":"form4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1604464/000090514826001143/form4.xml","form_type":"4"}},{"id":860674,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":19394,"kind":"person","name":"Nguyen AnhCo","position":1,"cik":"0001977970","reported_name":"Nguyen 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These shares were purchased in multiple transactions ranging from $11.83 to $12.44, inclusive. The Reporting Person undertake to provide to the Issuer, any securityholder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth above."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Represents securities held by Panacea Venture Healthcare Fund II, L.P."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"James Huang is the sole owner of Panacea Innovation Limited, which is the sole owner of Panacea Venture Healthcare Fund II GP Company, Ltd. (\"Fund II GP\") and Panacea Opportunity Fund I GP Company, Ltd. (\"Opportunity Fund GP\"), which are the general partners of Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P. 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the warrant held by such holder, to the extent that, after giving effect to the attempted exercise set forth in a notice of exercise, such holder, together with such holder's affiliates and any other person whose beneficial ownership of common stock, par value $0.0001 per share (the \"Common Stock\"), of the Issuer would be aggregated with such holder's for the purposes of Section 13(d) of the Exchange Act, and the applicable regulations of the U.S. Securities and Exchange Commission (the \"SEC\"), including any \"group\" of which such holder is a member, would beneficially own a number of shares of Common Stock in excess of the Beneficial Ownership Limitation."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F5","text":"The \"Beneficial Ownership Limitation\" is 19.99% of the shares of Common Stock then issued and outstanding, which percentage may be changed at a holder's election upon 61 days' notice to the Issuer."},{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F1","text":"In addition to Adiumentum Capital Fund I LP, a limited partnership organized under the laws of Delaware (\"Adiumentum\"), this Form 4 is being filed jointly by Adiumentum Capital Fund I GP LLC, a limited liability company organized under the laws of Delaware and the general partner of Adiumentum (\"Adiumentum GP\"), and Gregory A. 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Mr. Ciongoli, as the managing partner of Adiumentum, and as the managing member of Adiumentum GP, may be deemed to have the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) all the Subject Securities."}],"balance_after":377193,"derivative":{"exercise_price":0.0001,"underlying":"Common Stock"},"source":{"system":"sec-edgar","filing":"0001104659-25-050116","document":"tm2515303-1_4seq1.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2023732/000110465925050116/tm2515303-1_4seq1.xml","form_type":"4"}},{"id":1145773,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":79690,"kind":"person","name":"Adiumentum Capital Fund I LP","position":1,"cik":"0002023734","reported_name":"Adiumentum Capital Fund I LP","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":true,"other_text":"See remarks"}},{"id":79691,"kind":"person","name":"Adiumentum Capital Fund I GP LLC","position":2,"cik":"0002023736","reported_name":"Adiumentum Capital Fund I GP LLC","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":true,"other_text":"See remarks"}},{"id":19139,"kind":"person","name":"Ciongoli Gregory Austin","position":3,"cik":"0002023732","reported_name":"Ciongoli Gregory Austin","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":true,"other_text":"See remarks"}}],"security":"Common Stock","published_at":"2025-05-16T22:26:21.000Z","date":"2025-05-16","kind":"grant","planned":false,"acquired":true,"shares":75572,"price":6.61,"value":499530.92,"ownership":{"direct":true},"footnotes":[{"field":"ownership.direct","element":"directOrIndirectOwnership","label":"F1","text":"In addition to Adiumentum Capital Fund I LP, a limited partnership organized under the laws of Delaware (\"Adiumentum\"), this Form 4 is being filed jointly by Adiumentum Capital Fund I GP LLC, a limited liability company organized under the laws of Delaware and the general partner of Adiumentum (\"Adiumentum GP\"), and Gregory A. 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Mr. Ciongoli, as the managing partner of Adiumentum, and as the managing member of Adiumentum GP, may be deemed to have the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) all the Subject Securities."}],"balance_after":1209395,"source":{"system":"sec-edgar","filing":"0001104659-25-050116","document":"tm2515303-1_4seq1.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2023732/000110465925050116/tm2515303-1_4seq1.xml","form_type":"4"}},{"id":1182555,"issuer":{"id":6828,"kind":"organization","name":"Atara Biotherapeutics, Inc.","symbol":"ATRA"},"owners":[{"id":30454,"kind":"person","name":"Hyllengren Eric J","position":1,"cik":"0001966926","reported_name":"Hyllengren Eric J","relationship":{"other":true,"other_text":"Former EVP, CFO & COO"}}],"security":"Employee Stock Option (Right to 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