[SCHEDULE 13G/A] Mersana Therapeutics, Inc. SEC Filing

Rhea-AI Filing Summary

Schonfeld Strategic Advisors LLC reported beneficial ownership of 5,673,852 shares of Mersana Therapeutics, Inc. (ticker MRSN), representing 4.55% of the company's common stock. The filing states Schonfeld has sole voting and sole dispositive power over all 5,673,852 shares and that these shares are held in accounts for clients, including separately managed accounts. The 4.55% figure is calculated using 124,631,339 shares outstanding as disclosed in Mersana's definitive proxy statement dated May 9, 2025. Schonfeld affirms the securities were acquired in the ordinary course of business and not to influence control of the issuer.

Positive

• Clear disclosure of ownership: reporting of exact share count (5,673,852) and percentage (4.55%) with voting and dispositive powers specified
• Supports transparency and compliance: includes citation to the issuer's proxy statement for the outstanding share count and a signed certification by the Chief Compliance Officer

Negative

• Stake below 5% threshold: at 4.55% the position is not a >5% holding and therefore is less likely to be material to control or trigger certain investor protections
• No indication of intent or strategy: filing states shares were acquired in the ordinary course and not to influence control, limiting actionable insight for investors

Insights

Securities Analyst

TL;DR: Schonfeld reports a 4.55% stake with sole voting and dispositive power; position is disclosed as ordinary-course, not control-seeking.

Schonfeld's Schedule 13G/A shows a non-controlling position below the 5% reporting threshold that typically triggers heightened disclosure under certain rules. The firm discloses full sole voting and dispositive authority over 5,673,852 shares and cites the issuer's proxy statement for the 124,631,339-share denominator. This filing is a routine transparency disclosure by an investment adviser managing client accounts rather than an activist or control-seeking event.

Compliance / Governance Expert

TL;DR: Filing appears compliant and complete: identity, address, share counts, and certification are provided.

The Schedule 13G/A includes required elements: filer identity and Delaware organization status, address, CUSIP, exact share counts, percentage calculation basis, and a certification signed by the Chief Compliance Officer. The statement expressly disclaims an intent to influence control and notes the shares are held in client accounts, including Schonfeld SMAs, which is consistent with an investment-adviser filing under the ordinary-course standard.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Mersana Therapeutics, Inc.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

59045L106

(CUSIP Number)

06/30/2025

(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. 59045L106

1

Names of Reporting Persons

Schonfeld Strategic 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 5,673,852.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 5,673,852.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

5,673,852.00

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)

4.55 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: The percentage of the issuer's common stock beneficially owned by the reporting person reflects 124,631,339 shares of common stock outstanding as of May 9, 2025, as set forth in the issuer's definitive proxy statement filed by the issuer with the Securities and Exchange Commission on May 15, 2025.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Mersana Therapeutics, Inc.
(b)	Address of issuer's principal executive offices: 840 Memorial Drive, Cambridge, Massachusetts 02139
Item 2.
(a)	Name of person filing: Schonfeld Strategic Advisors LLC ("Schonfeld") is an investment adviser to several private funds. Schonfeld also engages third party sub-advisers to manage assets of its private funds as separately managed accounts (the "Schonfeld SMAs"). Accordingly, Schonfeld may be deemed to indirectly beneficially own securities owned by the Schonfeld SMAs. Each Schonfeld SMA is the record and direct beneficial owner of a portion of the securities covered by this statement. Schonfeld declares that neither the filing of this statement nor anything herein shall be construed as an admission that such person is, for the purposes of Section 13(d) or 13(g) of the Securities Exchange Act of 1934 or any other purpose, the beneficial owner of any securities covered by this statement.
(b)	Address or principal business office or, if none, residence: 590 Madison Avenue, 23rd Floor, New York, New York 10022
(c)	Citizenship: Delaware limited liability company
(d)	Title of class of securities: Common Stock, par value $0.0001 per share
(e)	CUSIP No.: 59045L106
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: 5,673,852 shares
(b)	Percent of class: 4.55%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 5,673,852 shares
	(ii) Shared power to vote or to direct the vote: 0 shares
	(iii) Sole power to dispose or to direct the disposition of: 5,673,852 shares
	(iv) Shared power to dispose or to direct the disposition of: 0 shares
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	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. The securities held by each of the Schonfeld SMAs as to which this statement is filed are owned of record by clients of Schonfeld. Those clients have the right to receive, or the power to direct the receipt of, dividends from, or the proceeds from the sale of, such securities.
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 acquired and are held in the ordinary course of business and 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.

Schonfeld Strategic Advisors LLC

Signature:	/s/ Hung Luc
Name/Title:	Hung Luc, Chief Compliance Officer
Date:	08/14/2025

FAQ

What stake in Mersana Therapeutics (MRSN) does Schonfeld report?

Schonfeld reports beneficial ownership of 5,673,852 shares, equal to 4.55% of Mersana's common stock.

Does Schonfeld have voting control over the shares?

Yes. The filing states Schonfeld has sole voting power and sole dispositive power over all 5,673,852 shares.

Is this position considered a >5% ownership requiring different disclosures?

No. The reported ownership is 4.55%, which is below the 5% threshold referred to in Item 5 of the filing.

What basis was used to calculate the 4.55% figure?

The percentage is based on 124,631,339 shares outstanding as set forth in Mersana's definitive proxy statement dated May 9, 2025.

Who signed the Schedule 13G/A for Schonfeld?

Hung Luc, Chief Compliance Officer, signed the filing on behalf of Schonfeld Strategic Advisors LLC on 08/14/2025.