Sutro Biopharma Schedule 13G discloses that affiliated investment entities and Srinivas Akkaraju together beneficially own disclosed stakes in the company's common stock. The filing lists 419,095 shares held by Samsara BioCapital, 643,777 shares held by Samsara Opportunity Fund, and 1,062,872 shares beneficially owned by the Reporting Persons in aggregate. The filing uses 16,567,238 shares outstanding as of March 16, 2026 as the basis for percentage calculations and reports percentages of 2.5%, 3.9%, and 6.4% for the listed holders. The report is signed by Srinivas Akkaraju on behalf of the Samsara entities.
Positive
None.
Negative
None.
Insights
Passive ownership disclosed by investment affiliates and an associated manager.
The filing lists beneficial ownership by Samsara BioCapital, Samsara Opportunity Fund, their GP entities, and Srinivas Akkaraju, showing 1,062,872 shares attributable in aggregate. Percentages are calculated using 16,567,238 shares outstanding as of March 16, 2026.
Disclosure is typical for institutional holders; cash‑flow treatment or plans to buy/sell are not stated in the excerpt and future transactions would appear in subsequent filings.
Key Figures
Shares outstanding:16,567,238 sharesSamsara BioCapital holdings:419,095 sharesSamsara Opportunity Fund holdings:643,777 shares+2 more
5 metrics
Shares outstanding16,567,238 sharesas of March 16, 2026
Samsara BioCapital holdings419,095 sharesdirectly held by Samsara LP
Samsara Opportunity Fund holdings643,777 sharesdirectly held by Samsara Opportunity Fund
Aggregate beneficial ownership1,062,872 sharesaggregate reported for the Reporting Persons
Percent of class (example)6.4%percentage corresponding to 1,062,872 of 16,567,238 shares
Key Terms
beneficially owned, shared dispositive power, Schedule 13G, general partner
4 terms
beneficially ownedregulatory
"Row 9 of each Reporting Person's cover page to this sets forth the aggregate number"
Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.
shared dispositive powerregulatory
"Shared Dispositive Power 419,095.00"
Schedule 13Gregulatory
"Item 1. (a) Name of issuer: Sutro Biopharma, Inc."
A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.
general partnerfinancial
"Samsara GP is the sole general partner of Samsara LP"
A general partner is the person or firm that runs an investment partnership and legally represents it — they make the day-to-day decisions, choose which assets to buy or sell, and are responsible for the partnership’s obligations. Investors care because the general partner’s judgment, risk-taking and fee and profit-sharing arrangements determine both the potential returns and the level of exposure to losses; think of the GP as the ship’s captain whose skill and honesty shape the voyage’s outcome.
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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
Sutro Biopharma, Inc.
(Name of Issuer)
Common Stock, $0.001 par value per share
(Title of Class of Securities)
869367201
(CUSIP Number)
02/11/2026
(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)
schemaVersion:
SCHEDULE 13G
CUSIP Number(s):
869367201
1
Names of Reporting Persons
Samsara BioCapital, L.P.
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
419,095.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
419,095.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
419,095.00
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)
2.5 %
12
Type of Reporting Person (See Instructions)
PN
SCHEDULE 13G
CUSIP Number(s):
869367201
1
Names of Reporting Persons
Samsara BioCapital GP, 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
419,095.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
419,095.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
419,095.00
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)
2.5 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
CUSIP Number(s):
869367201
1
Names of Reporting Persons
Samsara Opportunity Fund, L.P.
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
643,777.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
643,777.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
643,777.00
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)
3.9 %
12
Type of Reporting Person (See Instructions)
PN
SCHEDULE 13G
CUSIP Number(s):
869367201
1
Names of Reporting Persons
Samsara Opportunity Fund GP, 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
643,777.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
643,777.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
643,777.00
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)
3.9 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
CUSIP Number(s):
869367201
1
Names of Reporting Persons
Srinivas Akkaraju
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
1,062,872.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,062,872.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,062,872.00
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)
6.4 %
12
Type of Reporting Person (See Instructions)
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, CA, 94080.
Item 2.
(a)
Name of person filing:
The names of the persons filing this report (collectively, the "Reporting Persons") are:
Samsara BioCapital, L.P. ("Samsara LP")
Samsara BioCapital GP, LLC ("Samsara GP")
Samsara Opportunity Fund, L.P. ("Samsara Opportunity Fund")
Samsara Opportunity Fund GP, LLC ("Samsara Opportunity GP")
Srinivas Akkaraju ("Dr. Akkaraju")
The Reporting Persons expressly disclaim status as a "group" for purposes of this Schedule 13G.
(b)
Address or principal business office or, if none, residence:
Samsara LP Delaware
Samsara GP Delaware
Samsara Opportunity Fund Delaware
Samsara Opportunity GP Delaware
Dr. Akkaraju United States
(d)
Title of class of securities:
Common Stock, $0.001 par value per share
(e)
CUSIP Number(s):
869367201
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).
Item 4.
Ownership
(a)
Amount beneficially owned:
Row 9 of each Reporting Person's cover page to this Schedule 13G sets forth the aggregate number of shares of common stock of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.
The Reporting Persons' ownership of the Issuer's securities consists of (i) 419,095 shares of common stock directly held by Samsara LP and (ii) 643,777 shares of common stock directly held by Samsara Opportunity Fund.
Samsara GP is the sole general partner of Samsara LP and Dr. Akkaraju is the managing member of Samsara GP. Each of Samsara GP and Dr. Akkaraju possesses power to direct the voting and disposition of the securities held by Samsara LP.
Samsara Opportunity GP is the sole general partner of Samsara Opportunity Fund and Dr. Akkaraju is the managing member of Samsara Opportunity GP. Each of Samsara Opportunity GP and Dr. Akkaraju possesses power to direct the voting and disposition of the securities held by Samsara Opportunity Fund.
(b)
Percent of class:
Row 11 of each Reporting Person's cover page to this Schedule 13G sets forth the percentages of shares of common stock of the Issuer beneficially owned by such Reporting Person and is incorporated by reference. The percentage set forth in each row 11 is based upon 16,567,238 shares outstanding as of March 16, 2026, as reported in the Issuer's Annual Report on Form 10-K filed with the Securities and Exchange Commission (the "SEC") on March 23, 2026.
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
Row 5 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.
(ii) Shared power to vote or to direct the vote:
Row 6 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.
(iii) Sole power to dispose or to direct the disposition of:
Row 7 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.
(iv) Shared power to dispose or to direct the disposition of:
Row 8 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.
Item 5.
Ownership of 5 Percent or Less of a Class.
Not Applicable
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
Not Applicable
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
Not Applicable
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.
Samsara BioCapital, L.P.
Signature:
/s/ Srinivas Akkaraju
Name/Title:
By Samsara BioCapital GP, LLC, its General Partner, By Srinivas Akkaraju, Managing Member
Date:
05/15/2026
Samsara BioCapital GP, LLC
Signature:
/s/ Srinivas Akkaraju
Name/Title:
By Srinivas Akkaraju, Managing Member
Date:
05/15/2026
Samsara Opportunity Fund, L.P.
Signature:
/s/ Srinivas Akkaraju
Name/Title:
By Samsara Opportunity Fund GP, LLC, its General Partner, By Srinivas Akkaraju, Managing Member
What stake does Samsara BioCapital report in Sutro Biopharma (STRO)?
Samsara BioCapital reports 419,095 shares of common stock. The filing states this equals 2.5% of 16,567,238 shares outstanding as of March 16, 2026, with voting and dispositive power held jointly as described.
How many shares does Samsara Opportunity Fund report owning in STRO?
Samsara Opportunity Fund reports 643,777 shares of common stock, equal to 3.9% of the 16,567,238 shares outstanding as of March 16, 2026, and the filing attributes shared voting and dispositive power to affiliated GP entities.
What aggregate ownership do the Reporting Persons disclose for STRO?
The Reporting Persons disclose an aggregate of 1,062,872 shares beneficially owned across the listed entities. The filing uses 16,567,238 shares outstanding as of March 16, 2026 to compute the reported percentages.
Who signed the Schedule 13G for Sutro Biopharma (STRO)?
The Schedule 13G is signed by Srinivas Akkaraju on behalf of Samsara BioCapital GP, Samsara Opportunity Fund GP and in his individual capacity, with signature dates shown as 05/15/2026 in the excerpt.
What voting or dispositive power is reported by the filers for STRO shares?
The filing shows 0 sole voting/dispositive power and reports shared voting and shared dispositive power for the listed holdings (e.g., 419,095 and 643,777 shared powers), as set out on the cover rows incorporated by reference.
