Perceptive reports 5.4% stake in Sutro Biopharma

Sutro Biopharma, Inc. beneficial ownership filing: Perceptive Advisors, Joseph Edelman and Perceptive Life Sciences Master Fund, Ltd. report shared beneficial ownership of 898,025 shares of Common Stock, equal to 5.4% of the class.

Rhea-AI Filing Summary

Sutro Biopharma, Inc. beneficial ownership filing: Perceptive Advisors, Joseph Edelman and Perceptive Life Sciences Master Fund, Ltd. report shared beneficial ownership of 898,025 shares of Common Stock, equal to 5.4% of the class. Shares outstanding were 16,567,238 as of March 16, 2026.

The Master Fund directly holds 898,025 shares; Perceptive Advisors is the fund's investment manager and Mr. Edelman is its managing member and may be deemed to beneficially own the shares. The filing is signed by Joseph Edelman.

Insights

Corporate Governance Analyst

Perceptive and affiliated entities report a passive >5% stake in Sutro Biopharma.

Schedule 13G shows the Master Fund directly holds 898,025 shares and reports 5.4% ownership based on 16,567,238 shares outstanding as of March 16, 2026. The filing attributes shared voting and dispositive power to the reporting persons.

Because the form is a 13G, the filing generally signals passive investment rather than an activist intent; future 13D filings would indicate active engagement. Subsequent filings may disclose changes in position or voting arrangements.

Key Figures

Shares held: 898,025 shares Percent of class: 5.4% Shares outstanding: 16,567,238 shares +2 more

5 metrics

Shares held 898,025 shares Direct holdings by Perceptive Life Sciences Master Fund

Percent of class 5.4% Ownership percentage reported for Perceptive Advisors and affiliates

Shares outstanding 16,567,238 shares Shares outstanding used as basis, as of <date>March 16, 2026</date>

Form type Schedule 13G Passive investor beneficial ownership disclosure

CUSIP 869367201 Identifier for Sutro Biopharma common stock

Key Terms

Schedule 13G, Beneficially owned, Shared Dispositive Power, Shares outstanding

4 terms

Schedule 13G regulatory

"reporting this Schedule 13G shows beneficial ownership"

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.

Beneficially owned financial

"The Master Fund directly holds 898,025 shares of Common Stock"

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 Power regulatory

"Shared Dispositive Power 898,025.00"

Shares outstanding market

"based on 16,567,238 shares of Common Stock outstanding as of March 16, 2026"

Shares outstanding are the total number of a company’s stock units held by all shareholders, including institutional investors and company insiders — think of them as the total number of slices of the company’s ownership pie. Investors use this number to calculate how much of the company each share represents, and it directly affects per-share measures like earnings per share, ownership percentage and valuation; when the slice count changes, an investor’s claim and the company’s per-share metrics change too.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stake does Perceptive Advisors report in Sutro Biopharma (STRO)?

They report beneficial ownership of 898,025 shares, equal to 5.4% of the outstanding common stock. This percentage is calculated using 16,567,238 shares outstanding as of March 16, 2026, per the filing's stated basis.

Who legally holds the 898,025 Sutro shares reported by Perceptive?

The Perceptive Life Sciences Master Fund, Ltd. directly holds the 898,025 shares. Perceptive Advisors is the fund’s investment manager and Joseph Edelman is the managing member, each deemed to beneficially own the shares in the filing.

Does the Schedule 13G filing indicate active control or activism?

No. A Schedule 13G typically indicates a passive investor reporting ownership above 5%. The filing lists shared voting and dispositive power but does not state activist intent; a Schedule 13D would show activist intentions if filed.

What voting and dispositive powers are reported for these holdings?

The filing shows 0 sole voting and dispositive power and 898,025 shares of shared voting and shared dispositive power for each reporting person, as reported on the cover rows of the Schedule 13G.

What basis did the filing use to calculate the 5.4% ownership figure?

The percentage is based on 16,567,238 shares outstanding as of March 16, 2026, cited from Sutro Biopharma’s Annual Report on Form 10-K, as referenced in the Schedule 13G ownership disclosure.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 04/21/2026 - 04:19 PM EDT Learn about SEC filing dates

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

(Title of Class of Securities)

869367201

(CUSIP Number)

04/14/2026

(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 898,025.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 898,025.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

898,025.00

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)

5.4 %

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 898,025.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 898,025.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

898,025.00

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)

5.4 %

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 898,025.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 898,025.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

898,025.00

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)

5.4 %

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 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: 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 are based on 16,567,238 shares of Common Stock 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 on March 23, 2026. The Master Fund directly holds 898,025 shares of Common Stock. Perceptive Advisors serves as the investment manager to 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: 5.4% Mr. Edelman: 5.4% Master Fund: 5.4%
(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: 898,025 Mr. Edelman: 898,025 Master Fund: 898,025
	(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: 898,025 Mr. Edelman: 898,025 Master Fund: 898,025
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:	04/21/2026

Joseph Edelman

Signature:	/s/ Joseph Edelman
Name/Title:	Joseph Edelman
Date:	04/21/2026

Perceptive Life Sciences Master Fund, Ltd.

Signature:	/s/ Joseph Edelman
Name/Title:	Joseph Edelman, Managing Member
Date:	04/21/2026

Exhibit Information

Exhibit 99.1 - Joint Filing Agreement