SCHEDULE 13G/A 0001425738 XXXXXXXX LIVE 10 Common Stock, par value $0.0001 per share 03/31/2025 0001604464 Atara Biotherapeutics, Inc. 046513206 1280 Rancho Conejo Blvd Thousand Oaks CA 91320 Rule 13d-1(c) Rule 13d-1(d) Redmile Group, LLC DE 0.00 601243.00 0.00 601243.00 601243.00 N 9.9 IA OO Redmile Group, LLC's beneficial ownership of the Issuer's common stock ("Common Stock") is comprised of 441,701 shares of Common Stock owned by certain private investment vehicles managed by Redmile Group, LLC (the "Redmile Funds"), including RedCo I, L.P. ("RedCo I") and Redmile Biopharma Investments II, L.P. ("RBI II"). Subject to the Beneficial Ownership Blocker (as defined below), Redmile Group, LLC may also be deemed to beneficially own 2,732,047 shares of Common Stock issuable upon exercise of certain pre-funded warrants to purchase Common Stock (the "Warrants"). Pursuant to the terms of the Warrants, the Issuer may not effect any exercise of the Warrant, and a holder of a Warrant does not have the right to exercise the Warrant held by such holder, to the extent that after giving effect to such issuance after exercise, the holder (together with the holder's affiliates, and any other persons acting as a group together with the holder or any of the holder's affiliates), would beneficially own in excess of 9.99% (the "Beneficial Ownership Limitation") of the number of shares of Common Stock outstanding immediately after giving effect to the issuance of shares of Common Stock issued upon exercise of the Warrant (the "Beneficial Ownership Blocker"). The Beneficial Ownership Limitation may be changed at a holder's election upon 61 days' notice to the Issuer. The 601,243 shares of Common Stock reported as beneficially owned by Redmile Group, LLC in this Schedule 13G represent 9.99% of the outstanding shares of Common Stock (calculated in accordance with the footnote below). The reported securities may be deemed beneficially owned by Redmile Group, LLC as investment manager of the Redmile Funds. The reported securities may also be deemed beneficially owned by Jeremy C. Green as the principal of Redmile Group, LLC. Redmile Group, LLC and Mr. Green each disclaim beneficial ownership of these shares, except to the extent of its or his pecuniary interest in such shares, if any. Percentage based on: (i) 5,858,909 shares of Common Stock outstanding as of March 3, 2025, as reported by the Issuer in its Form 10-K for the fiscal year ended December 31, 2024 filed with the Securities and Exchange Commission on March 7, 2025 (the "Form 10-K"); plus (ii) 159,542 shares of Common Stock issuable upon exercise of the Warrants, which due to the Beneficial Ownership Limitation is the maximum number of shares that could be issued upon exercise of the Warrants. Jeremy C. Green X0 0.00 601243.00 0.00 601243.00 601243.00 N 9.9 HC IN Jeremy C. Green's beneficial ownership of Common Stock is comprised of 441,701 shares of Common Stock owned by the Redmile Funds, including RedCo I and RBI II. Subject to the Beneficial Ownership Blocker, Mr. Green may also be deemed to beneficially own 2,732,047 shares of Common Stock issuable upon exercise of the Warrants. Pursuant to the terms of the Warrants, the Issuer may not effect any exercise of the Warrant, and a holder of a Warrant does not have the right to exercise the Warrant held by such holder, to the extent that the Beneficial Ownership Blocker applies. The 601,243 shares of Common Stock reported as beneficially owned by Mr. Green in this Schedule 13G represent 9.99% of the outstanding shares of Common Stock (calculated in accordance with the footnote below). The reported securities may be deemed beneficially owned by Redmile Group, LLC as investment manager of the Redmile Funds. The reported securities may also be deemed beneficially owned by Jeremy C. Green as the principal of Redmile Group, LLC. Redmile Group, LLC and Mr. Green each disclaim beneficial ownership of these shares, except to the extent of its or his pecuniary interest in such shares, if any. Percentage based on: (i) 5,858,909 shares of Common Stock outstanding as of March 3, 2025, as reported by the Issuer in the Form 10-K; plus (ii) 159,542 shares of Common Stock issuable upon exercise of the Warrants, which due to the Beneficial Ownership Limitation is the maximum number of shares that could be issued upon exercise of the Warrants. RedCo I, L.P. DE 0.00 347442.00 0.00 347442.00 347442.00 N 5.8 PN The shares of Common Stock reported as beneficially owned by RedCo I in this Schedule 13G represent the 191,226 shares of Common Stock held directly by RedCo I and the 156,216 shares of Common Stock that could be issued to RedCo I upon exercise of the Warrants directly held by RedCo I. Percentage based on: (i) 5,858,909 shares of Common Stock outstanding as of March 3, 2025, as reported by the Issuer in the Form 10-K; plus (ii) 156,216 shares of Common Stock issuable upon exercise of the Warrants directly held by RedCo I. Redmile Biopharma Investments II, L.P. DE 0.00 302173.00 0.00 302173.00 302173.00 N 5.0 PN As of March 7, 2025, an increase in the issuer's outstanding Common Stock disclosed in the Form 10-K increased the capacity under the Beneficial Ownership Blocker applicable to the Warrants directly held by RBI II, and caused RBI II's beneficial ownership to exceed five percent of the issuer's outstanding Common Stock. RBI II has joined this Schedule 13G amendment to file its initial report pursuant to Rule 13d-1(d). RBI II's beneficial ownership of Common Stock is comprised of 142,631 shares of Common Stock directly held by RBI II. Subject to the Beneficial Ownership Blocker, RBI II may also be deemed to beneficially own 1,507,640 shares of Common Stock issuable upon exercise of the Warrants directly held by RBI II. Pursuant to the terms of the Warrants, the Issuer may not effect any exercise of any Warrant, and a holder of a Warrant does not have the right to exercise any portion of the Warrant held by such holder, if the Beneficial Ownership Blocker applies. The shares of Common Stock reported as beneficially owned by RBI II in this Schedule 13G represent the shares of Common Stock held directly by RBI II and the 159,542 shares of Common Stock that could be issued to RBI II upon exercise of certain of the Warrants directly held by RBI II under the Beneficial Ownership Blocker. Percentage based on: (i) 5,858,909 shares of Common Stock outstanding as of March 3, 2025, as reported by the Issuer in the Form 10-K; plus (ii) 159,542 shares of Common Stock issuable upon exercise of the Warrants directly held by RBI II, which due to the Beneficial Ownership Limitation is the maximum number of shares that could be issued upon exercise of the Warrants. Atara Biotherapeutics, Inc. 1280 Rancho Conejo Blvd, Thousand Oaks, CA, 91320 Redmile Group, LLC Jeremy C. Green RedCo I, L.P. Redmile Biopharma Investments II, L.P. Redmile Group, LLC One Letterman Drive Building D, Suite D3-300 The Presidio of San Francisco San Francisco, California 94129 Jeremy C. Green c/o Redmile Group, LLC (NY Office) 45 W. 27th Street, Floor 11 New York, NY 10001 RedCo I, L.P. c/o Redmile Group, LLC One Letterman Drive Building D, Suite D3-300 The Presidio of San Francisco San Francisco, California 94129 Redmile Biopharma Investments II, L.P. c/o Redmile Group, LLC One Letterman Drive Building D, Suite D3-300 The Presidio of San Francisco San Francisco, California 94129 Redmile Group, LLC: Delaware Jeremy C. Green: United Kingdom RedCo I, L.P.: Delaware Redmile Biopharma Investments II, L.P.: Delaware Y Redmile Group, LLC - 601,243 (1) Jeremy C. Green - 601,243 (1) RedCo I, L.P. - 347,442 (2) Redmile Biopharma Investments II, L.P. - 302,173 (3) Redmile Group, LLC - 9.9% (4) Jeremy C. Green - 9.9% (4) RedCo I, L.P. - 5.8% (5) Redmile Biopharma Investments II, L.P. - 5.0% (6) Redmile Group, LLC - 0 Jeremy C. Green - 0 RedCo I, L.P. - 0 Redmile Biopharma Investments II, L.P. - 0 Redmile Group, LLC - 601,243 (1) Jeremy C. Green - 601,243 (1) RedCo I, L.P. - 347,442 (2) Redmile Biopharma Investments II, L.P. - 302,173 (3) Redmile Group, LLC - 0 Jeremy C. Green - 0 RedCo I, L.P. - 0 Redmile Biopharma Investments II, L.P. - 0 Redmile Group, LLC - 601,243 (1) Jeremy C. Green - 601,243 (1) RedCo I, L.P. - 347,442 (2) Redmile Biopharma Investments II, L.P. - 302,173 (3) (1) Redmile Group, LLC's and Jeremy C. Green's beneficial ownership of the Issuer's Common Stock is comprised of 441,701 shares of Common Stock owned by the Redmile Funds, including RedCo I and RBI II. Subject to the Beneficial Ownership Blocker, Redmile Group, LLC and Mr. Green may also be deemed to beneficially own 2,732,047 shares of Common Stock issuable upon exercise of the Warrants. Pursuant to the terms of the Warrants, the Issuer may not effect any exercise of any Warrant, and a holder of a Warrant does not have the right to exercise any portion of the Warrant held by such holder, if the Beneficial Ownership Blocker applies. The 601,243 shares of Common Stock reported as beneficially owned by Redmile Group, LLC and Mr. Green in this Schedule 13G represent 9.99% of the outstanding shares of Common Stock (calculated in accordance with footnote (4) below). The reported securities may be deemed beneficially owned by Redmile Group, LLC as investment manager of the Redmile Funds. The reported securities may also be deemed beneficially owned by Jeremy C. Green as the principal of Redmile Group, LLC. Redmile Group, LLC and Mr. Green each disclaim beneficial ownership of these shares, except to the extent of its or his pecuniary interest in such shares, if any. (2) The shares of Common Stock reported as beneficially owned by RedCo I in this Schedule 13G represent the 191,226 shares of Common Stock held directly by RedCo I and the 156,216 shares of Common Stock that could be issued to RedCo I upon exercise of the Warrants directly held by RedCo I. (3) RBI II's beneficial ownership of Common Stock is comprised of 142,631 shares of Common Stock. Subject to the Beneficial Ownership Blocker, RBI II may also be deemed to beneficially own 1,507,640 shares of Common Stock issuable upon exercise of the Warrants directly held by RBI II. Pursuant to the terms of the Warrants, the Issuer may not effect any exercise of any Warrant, and a holder of a Warrant does not have the right to exercise any portion of the Warrant held by such holder, if the Beneficial Ownership Blocker applies. The shares of Common Stock reported as beneficially owned by RBI II in this Schedule 13G represent the shares of Common Stock held directly by RBI II and the 159,542 shares of Common Stock that could be issued to RBI II upon exercise of certain of the Warrants directly held by RBI II under the Beneficial Ownership Blocker. (4) Percentage based on: (i) 5,858,909 shares of Common Stock outstanding as of March 3, 2025, as reported by the Issuer in the Form 10-K; plus (ii) 159,542 shares of Common Stock issuable upon exercise of the Warrants, which due to the Beneficial Ownership Limitation is the maximum number of shares that could be issued upon exercise of the Warrants. (5) Percentage based on: (i) 5,858,909 shares of Common Stock outstanding as of March 3, 2025, as reported by the Issuer in the Form 10-K; plus (ii) 156,216 shares of Common Stock issuable upon exercise of the Warrants directly held by RedCo I. (6) Percentage based on: (i) 5,858,909 shares of Common Stock outstanding as of March 3, 2025, as reported by the Issuer in the Form 10-K; plus (ii) 159,542 shares of Common Stock issuable upon exercise of the Warrants directly held by RBI II, which due to the Beneficial Ownership Limitation is the maximum number of shares that could be issued upon exercise of the Warrants. Y Y N See the response to Item 4. Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Redmile Group, LLC /s/ Jeremy C. Green 05/15/2025 Jeremy C. Green /s/ Jeremy C. Green 05/15/2025 RedCo I, L.P. /s/ Jeremy C. Green 05/15/2025 Redmile Biopharma Investments II, L.P. /s/ Jeremy C. Green 05/15/2025