Sutro Biopharma, Inc. filed an amended Schedule 13G/A showing that Suvretta Capital Management, LLC, Averill Master Fund, Ltd., and Aaron Cowen no longer beneficially own any of its common stock. As of the event date of 12/31/2025, each reporting person discloses beneficial ownership of 0 shares, representing 0% of Sutro’s common stock, with no sole or shared voting or dispositive power.
The filing confirms that the group now owns 5% or less of the class. It also notes that all securities previously reported were directly owned by advisory clients of Suvretta Capital Management, LLC, and that no individual advisory client is deemed to own more than 5% of the common stock. The certification states that the securities were not acquired and are not held for the purpose of changing or influencing control of Sutro Biopharma.
What does the Schedule 13G/A filing for Sutro Biopharma (STRO) disclose?
The filing discloses that Suvretta Capital Management, Averill Master Fund, and Aaron Cowen now report 0 shares and 0% beneficial ownership of Sutro Biopharma common stock, indicating they no longer hold a reportable stake above 5% in the company.
Who are the reporting persons in the Sutro Biopharma (STRO) Schedule 13G/A?
The reporting persons are Suvretta Capital Management, LLC, Averill Master Fund, Ltd., and Aaron Cowen. They jointly report their ownership position in Sutro Biopharma’s common stock and now state that their beneficial ownership has declined to zero shares, or 0% of the class.
What percentage of Sutro Biopharma (STRO) does Suvretta Capital now own?
Suvretta Capital Management, LLC reports beneficial ownership of 0 shares of Sutro Biopharma common stock, representing 0% of the outstanding class. This indicates Suvretta is no longer a beneficial owner of 5% or more under SEC reporting rules.
What does “ownership of 5 percent or less” mean in the Sutro (STRO) filing?
“Ownership of 5 percent or less” means the reporting group’s stake in Sutro Biopharma common stock has fallen below the 5% threshold. At this level, they no longer qualify as significant beneficial owners requiring a larger-stake Schedule 13D-style disclosure under SEC rules.
Who actually held the Sutro Biopharma (STRO) shares referenced in the 13G/A?
The filing states all securities referenced were directly owned by advisory clients of Suvretta Capital Management, LLC. It further notes that none of those advisory clients may be deemed to beneficially own more than 5% of Sutro Biopharma’s common stock.
Does the Sutro Biopharma (STRO) 13G/A indicate an attempt to influence control?
No. The certification explicitly states the securities were not acquired and are not held for the purpose of changing or influencing control of Sutro Biopharma and are not part of any transaction intended to have that control-related effect.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 5)
Sutro Biopharma, Inc.
(Name of Issuer)
Common Stock, $0.001 par value
(Title of Class of Securities)
869367102
(CUSIP Number)
12/31/2025
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)
SCHEDULE 13G
CUSIP No.
869367102
1
Names of Reporting Persons
SUVRETTA CAPITAL MANAGEMENT, LLC
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
0.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
0.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
0.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
0 %
12
Type of Reporting Person (See Instructions)
IA, OO
SCHEDULE 13G
CUSIP No.
869367102
1
Names of Reporting Persons
AVERILL MASTER FUND, LTD.
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
CAYMAN ISLANDS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
0.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
0.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
0.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
0 %
12
Type of Reporting Person (See Instructions)
CO
SCHEDULE 13G
CUSIP No.
869367102
1
Names of Reporting Persons
AARON COWEN
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
0.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
0.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
0.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
0 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Sutro Biopharma, Inc.
(b)
Address of issuer's principal executive offices:
111 Oyster Point Blvd, South San Francisco, California, 94080
Item 2.
(a)
Name of person filing:
Suvretta Capital Management, LLC
Averill Master Fund, Ltd.
Aaron Cowen
(b)
Address or principal business office or, if none, residence:
Suvretta Capital Management, LLC
540 Madison Avenue, 7th Floor
New York, New York 10022
United States of America
Averill Master Fund, Ltd.
c/o Maples Corporate Services Limited
P.O. Box 309
Ugland House
Grand Cayman KY1-1104
Cayman Islands
Aaron Cowen
c/o Suvretta Capital Management, LLC
540 Madison Avenue, 7th Floor
New York, New York 10022
(c)
Citizenship:
Suvretta Capital Management, LLC - Delaware
Averill Master Fund, Ltd. - Cayman Islands
Aaron Cowen - United States
(d)
Title of class of securities:
Common Stock, $0.001 par value
(e)
CUSIP No.:
869367102
Item 3.
If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
(k)
Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Ownership of more than 5 Percent on Behalf of Another Person.
If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required.
All of the securities reported in this Schedule 13G are directly owned by advisory clients of Suvretta Capital Management, LLC. None of those advisory clients may be deemed to beneficially own more than 5% of the Common Stock, $0.001 par value.
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary.
Please see Exhibit B attached hereto.
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
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.
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
SUVRETTA CAPITAL MANAGEMENT, LLC
Signature:
___________________________________________
Name/Title:
Andrew Nathanson, General Counsel and Chief Compliance Officer
Date:
02/13/2026
AVERILL MASTER FUND, LTD.
Signature:
___________________________________________
Name/Title:
Andrew Nathanson, Authorized Signatory
Date:
02/13/2026
AARON COWEN
Signature:
___________________________________________
Name/Title:
Aaron Cowen
Date:
02/13/2026
Exhibit Information
[Exhibit A - Joint Filing Agreement]
[Exhibit B - Control Person Identification]
