[SCHEDULE 13G/A] Zymeworks Inc. Amended Passive Investment Disclosure
Rubric Capital reports 7.0M shares (9.49%) of Zymeworks
Zymeworks Inc. Schedule 13G/A filing: Rubric Capital Management and David Rosen report beneficial ownership of 7,000,000 shares of Zymeworks common stock, representing 9.49% of the class based on 73,749,607 shares outstanding as of February 6, 2026.
Zymeworks Inc. Schedule 13G/A filing: Rubric Capital Management and David Rosen report beneficial ownership of 7,000,000 shares of Zymeworks common stock, representing 9.49% of the class based on 73,749,607 shares outstanding as of February 6, 2026. The shares are held by Rubric Funds, including Rubric Capital Master Fund LP, which has voting and dispositive power shared among the Reporting Persons.
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Key Figures
Shares owned:7,000,000 sharesPercent of class:9.49%Shares outstanding:73,749,607 shares+1 more
4 metrics
Shares owned7,000,000 sharesBeneficially owned by Reporting Persons as stated on cover page
Percent of class9.49%Percent of class based on 73,749,607 shares outstanding
Shares outstanding73,749,607 sharesOutstanding as of February 6, 2026 per issuer's quarterly report
CUSIP98985Y108CUSIP for Zymeworks common stock on cover page
"Amount beneficially owned: The information required by Items 4(a) - (c)"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
Shared dispositive powerregulatory
"Shared Dispositive Power 7,000,000.00"
Schedule 13G/Aregulatory
"This statement is filed by: Rubric Capital Management LP"
A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.
FAQ
AI-generated questions and answers. How Rhea-AI works. Not financial advice.
What stake does Rubric Capital report in Zymeworks (ZYME)?
Rubric Capital reports beneficial ownership of 7,000,000 shares, equal to 9.49% of the class. The percentage is calculated using 73,749,607 shares outstanding as of February 6, 2026 from the issuer's cited quarterly report.
Who else is named on the Schedule 13G/A for ZYME?
The filing names Rubric Capital Management LP and David Rosen. Rubric is the investment adviser to Rubric Funds; Mr. Rosen is a managing member and is reported as a Reporting Person associated with those funds.
Does the filing state who controls voting or sale proceeds for the shares?
The cover page shows shared voting power and shared dispositive power of 7,000,000 shares. It also states that Rubric Capital Master Fund LP has the right to receive dividends or proceeds for more than 5% of the class.
What address and CUSIP are listed for the Zymeworks Schedule 13G/A?
The Reporting Persons' principal business address is 155 East 44th St, Suite 1630, New York, NY 10017. The CUSIP for Zymeworks common stock is 98985Y108, as shown on the cover page.
What date and filing signatures are provided on the amendment?
The amendment is signed by Michael Nachmani and David Rosen with signature dates of 05/15/2026. The cover page indicates an amendment number and includes the reported ownership data used in Item 4.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 2)
Zymeworks Inc.
(Name of Issuer)
Common Stock, $0.00001 par value per share
(Title of Class of Securities)
98985Y108
(CUSIP Number)
03/31/2026
(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):
98985Y108
1
Names of Reporting Persons
Rubric Capital Management LP
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
7,000,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
7,000,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
7,000,000.00
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)
9.49 %
12
Type of Reporting Person (See Instructions)
IA, PN
SCHEDULE 13G
CUSIP Number(s):
98985Y108
1
Names of Reporting Persons
David Rosen
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
7,000,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
7,000,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
7,000,000.00
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)
9.49 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Zymeworks Inc.
(b)
Address of issuer's principal executive offices:
108 Patriot Drive, Suite A Middletown, DE, 19709
Item 2.
(a)
Name of person filing:
This statement is filed by:
(i) Rubric Capital Management LP ("Rubric Capital"), the investment adviser to certain investment funds and/or accounts (collectively, the "Rubric Funds") that hold the shares of Common Stock, $0.00001 par value (the "Common Stock") of Zymeworks Inc., a Delaware corporation (the "Issuer") reported herein; and
(ii) David Rosen ("Mr. Rosen"), Managing Member of Rubric Capital Management GP LLC, the general partner of Rubric Capital.
The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons."
The filing of this statement should not be construed as an admission that any of the forgoing persons or any Reporting Person is, for the purposes of Section 13 of the Act, the beneficial owner of the shares of Common Stock reported herein.
(b)
Address or principal business office or, if none, residence:
The address of the principal business office of each of the Reporting Persons is 155 East 44th St, Suite 1630, New York, NY 10017.
(c)
Citizenship:
Rubric Capital is a Delaware limited partnership. Mr. Rosen is a citizen of the United States of America.
(d)
Title of class of securities:
Common Stock, $0.00001 par value per share
(e)
CUSIP No.:
98985Y108
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 Items 4(a) - (c) is set forth in Rows 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
The percentage set forth in Row (11) of the cover page for each of the Reporting Persons and in Item 4(b) is based on the 73,749,607 shares of Common Stock outstanding as of February 6, 2026, as reported in the Issuer's Quarterly Report on Form 10-K for the fiscal year ended December 31, 2026, filed with the Securities and Exchange Commission on March 2, 2026.
(b)
Percent of class:
9.49 %
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(ii) Shared power to vote or to direct the vote:
The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(iii) Sole power to dispose or to direct the disposition of:
The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(iv) Shared power to dispose or to direct the disposition of:
The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein 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.
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.
See Item 2(a). Rubric Capital Master Fund LP, a Rubric Fund, has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, more than 5% of the Common Stock.
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.
