Sutro Biopharma (STRO): Perceptive Advisors reports 7.9% beneficial stake

Rhea-AI Filing Summary

Perceptive Advisors LLC, Joseph Edelman, and Perceptive Life Sciences Master Fund, Ltd. report beneficial ownership of Sutro Biopharma common stock on an amended Schedule 13G basis. The Master Fund directly holds 1,304,846 shares of common stock, while Perceptive Advisors and Mr. Edelman may be deemed to beneficially own these shares through their respective roles.

This position represents 7.9% of Sutro Biopharma’s common stock, based on 16,572,171 shares outstanding as of August 7, 2026. The Reporting Persons have shared voting and dispositive power over the 1,304,846 shares and no sole voting or dispositive power.

Key Figures

Shares beneficially owned: 1,304,846 shares Ownership percentage: 7.9% Shares outstanding: 16,572,171 shares +2 more

5 metrics

Shares beneficially owned 1,304,846 shares Common stock of Sutro Biopharma held by Perceptive Life Sciences Master Fund, Ltd.

Ownership percentage 7.9% Portion of Sutro Biopharma common stock beneficially owned by each Reporting Person

Shares outstanding 16,572,171 shares Sutro Biopharma common stock outstanding as of August 7, 2026

Shared voting power 1,304,846 shares Shares over which the Reporting Persons have shared power to vote

Shared dispositive power 1,304,846 shares Shares over which the Reporting Persons have shared power to dispose

Key Terms

beneficially own, shared voting power, shared dispositive power, investment manager, +1 more

5 terms

beneficially own financial

"may be deemed to beneficially own the shares held by the Master Fund"

Beneficially own means having the economic rights and risks of a security—such as the right to receive dividends, sell the shares, or profit from price changes—whether or not your name appears on the official share register. Think of it like renting a car: you use it and reap the benefits even if the title lists someone else. Investors care because beneficial ownership determines who truly controls value, must be disclosed under securities rules, and can signal potential influence or trading activity that affects a stock’s price.

shared voting power financial

"Shared Voting Power 1,304,846.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

shared dispositive power financial

"Shared Dispositive Power 1,304,846.00"

investment manager financial

"Perceptive Advisors serves as the investment manager of the Master Fund"

Schedule 13G regulatory

"report this position on an amended Schedule 13G basis"

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.

FAQ

What percentage of SUTRO BIOPHARMA, INC. (STRO) does Perceptive Advisors report owning?

Perceptive Advisors, Joseph Edelman, and the Master Fund report beneficial ownership of 7.9% of Sutro Biopharma’s common stock, based on 16,572,171 shares outstanding as of August 7, 2026.

How many STRO shares are held by Perceptive Life Sciences Master Fund, Ltd.?

Perceptive Life Sciences Master Fund, Ltd. directly holds 1,304,846 shares of Sutro Biopharma common stock. Perceptive Advisors acts as investment manager, and Joseph Edelman is managing member of Perceptive Advisors.

Do the Reporting Persons have sole or shared voting power over STRO shares?

The Reporting Persons have shared voting power over 1,304,846 shares of Sutro Biopharma and no sole voting power. They also share dispositive power over the same number of shares.

Who are the Reporting Persons in this STRO Schedule 13G/A filing?

The Reporting Persons are Perceptive Advisors LLC, Joseph Edelman, and Perceptive Life Sciences Master Fund, Ltd.. They report beneficial ownership of Sutro Biopharma common stock as a group.

On what share count is the 7.9% STRO ownership stake based?

The reported 7.9% ownership stake is based on 16,572,171 shares of Sutro Biopharma common stock outstanding as of August 7, 2026, as stated in the company’s Form 10-Q.

Does Joseph Edelman directly hold any STRO shares in this filing?

Joseph Edelman does not directly hold any Sutro Biopharma shares. He may be deemed to beneficially own 1,304,846 shares through his role as managing member of Perceptive Advisors, which manages the Master Fund.

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Available on EDGAR 08/14/2026 - 05:22 PM Accepted by SEC EDGAR 08/14/2026 - 05:21 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

SUTRO BIOPHARMA, INC.

(Name of Issuer)

Common stock, $0.001 par value

(Title of Class of Securities)

869367201

(CUSIP Number)

06/30/2026

(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

Perceptive Advisors 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 1,304,846.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,304,846.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,304,846.00

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)

7.9 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

CUSIP Number(s): 869367201

1

Names of Reporting Persons

Joseph Edelman

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 1,304,846.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,304,846.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,304,846.00

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)

7.9 %

12

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13G

CUSIP Number(s): 869367201

1

Names of Reporting Persons

Perceptive Life Sciences 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 1,304,846.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,304,846.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,304,846.00

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)

7.9 %

12

Type of Reporting Person (See Instructions)

CO

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: The names of the persons filing this report (collectively, the "Reporting Persons") with respect to the Common Stock, $0.001 par value per share (the "Common Stock") of SUTRO BIOPHARMA, INC. (the "Issuer") are: (i) Perceptive Advisors LLC ("Perceptive Advisors") (ii) Joseph Edelman ("Mr. Edelman") (iii) Perceptive Life Sciences Master Fund, Ltd. (the "Master Fund")
(b)	Address or principal business office or, if none, residence: The address of the principal business office of each of the Reporting Persons is: 51 Astor Place, 10th Floor, New York, NY 10003
(c)	Citizenship: Perceptive Advisors is a Delaware limited liability company. Mr. Edelman is a United States citizen. The Master Fund is a Cayman Islands corporation.
(d)	Title of class of securities: Common stock, $0.001 par value
(e)	CUSIP No.: 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: The information required by this item with respect to each Reporting Person is set forth in Rows 5 through 9 and 11 of the cover pages to this Schedule 13G. The ownership percentages reported are based on 16,572,171 shares of Common Stock outstanding as of August 7, 2026, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 12, 2026. Neither Perceptive Advisors nor Mr. Edelman directly holds any shares of Common Stock. The Master Fund directly holds 1,304,846 shares of Common Stock. Perceptive Advisors serves as the investment manager of the Master Fund and may be deemed to beneficially own the shares held by the Master Fund. Mr. Edelman is the managing member of Perceptive Advisors and may be deemed to beneficially own the shares held by the Master Fund.
(b)	Percent of class: Perceptive Advisors: 7.9% Mr. Edelman: 7.9% Master Fund: 7.9%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: Perceptive Advisors: 0 Mr. Edelman: 0 Master Fund: 0
	(ii) Shared power to vote or to direct the vote: Perceptive Advisors: 1,304,846 Mr. Edelman: 1,304,846 Master Fund: 1,304,846
	(iii) Sole power to dispose or to direct the disposition of: Perceptive Advisors: 0 Mr. Edelman: 0 Master Fund: 0
	(iv) Shared power to dispose or to direct the disposition of: Perceptive Advisors: 1,304,846 Mr. Edelman: 1,304,846 Master Fund: 1,304,846
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.

Perceptive Advisors LLC

Signature:	/s/ Joseph Edelman
Name/Title:	Joseph Edelman, Managing Member
Date:	08/14/2026

Joseph Edelman

Signature:	/s/ Joseph Edelman
Name/Title:	Joseph Edelman
Date:	08/14/2026

Perceptive Life Sciences Master Fund, Ltd.

Signature:	/s/ Joseph Edelman
Name/Title:	Joseph Edelman, Managing Member
Date:	08/14/2026

Exhibit Information

Exhibit 99.1 - Joint Filing Agreement