As of November 6, 2026, 4 holders' latest Schedule 13D or 13G filings report owning 5% or more of Zymeworks Inc. The largest reported stake is EcoR1 Capital, LLC's, at 30.7%. 9 filings are on record since July 16, 2025 (Schedule 13D/A, November 19, 2025).
Sell to companies like Zymeworks Inc? Enter your website and see 10 with a filed reason to buy from you this month. Free.
Opens in a new tab. No signup.
Key facts
- · Holder: Rubric Capital Management LP · Percent: 9.49% · SCHEDULE 13G/A
- · Holder: Perceptive Advisors LLC · Percent: 5.4% · SCHEDULE 13G
- · Holder: Rubric Capital Management LP · Percent: 7.68% · SCHEDULE 13G/A
- · Holder: Morgan Stanley · Percent: 3.4% · SCHEDULE 13G/A
- · Holder: EcoR1 Capital, LLC · Percent: 30.7% · SCHEDULE 13D/A
Zymeworks Inc. has 9 Schedule 13D or 13G filings on record since 2025-07-16. 4 holders' latest filing reports 5% or more of common stock, $0.00001 par value per share. Each figure below is the holder's own, as filed, with the filing linked.
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| EcoR1 Capital, LLC | 30.7% | 22,970,388 | SCHEDULE 13D/A, 2025-11-19 | 2025-11-16 |
| Rubric Capital Management LP | 9.49% | 7,000,000 | SCHEDULE 13G/A, 2026-05-15 | 2026-03-31 |
| Perceptive Advisors LLC | 5.4% | 3,974,579 | SCHEDULE 13G, 2026-04-15 | 2026-04-08 |
| Bvf Partners L P | 5.2% | 3,938,641 | SCHEDULE 13G/A, 2025-11-14 | 2025-09-30 |
| Redmile Group, LLC | 4.9% | 3,705,750 | SCHEDULE 13G/A, 2025-11-14 | 2025-09-30 |
| BlackRock, Inc. | 4.8% | 3,559,828 | SCHEDULE 13G/A, 2025-07-16 | 2025-06-30 |
| 3.4% | 2,519,243 | SCHEDULE 13G/A, 2026-02-12 | 2025-12-31 |
Holding shares or following this stake? See who's behind Zymeworks Inc. and the warning signs.
Free to see. No signup.
Keep reading
More on Zymeworks Inc. and the records around it.
Zymeworks Inc. elsewhere on the record
- Leadership changes Apr 2026
- Who owns it
Companies that share a holder
- Redmile Group, LLC also filed stake reports on 18 other companies: FATE THERAPEUTICS INC (Nov 2026), Electra Therapeutics, Inc. (Sep 2026), Neurogene Inc. (Aug 2026)
- EcoR1 Capital, LLC also filed stake reports on 20 other companies: Mereo BioPharma Group plc (Aug 2026), Alto Neuroscience, Inc. (Jul 2026), Fulcrum Therapeutics, Inc. (Jun 2026)
- Rubric Capital Management LP also filed stake reports on 32 other companies: ARDELYX, INC. (Aug 2026), Enovis Corporation (Aug 2026), MeiraGTx Holdings plc (Aug 2026)
Watch Zymeworks Inc.
Get an email when Zymeworks Inc. files again: a new raise, a leadership change, a layoff or an IPO filing. One email first to confirm; nothing else until you click it. At most one a day, one click to stop. Free for up to 3 companies.
Want the whole picture on Zymeworks Inc.?
Example from a real report (our sample on Target): “In March 2026, Target announced a planned incremental $1 billion operating investment” Source: Target Corporation (press release)
A Full Report on Zymeworks Inc.: verified, sourced, every claim cited, ready in a few minutes. See pricing.
What the Full Report on Zymeworks Inc. covers
The Short Answer
Which Company This Is
What They Do, And How The Money Works
Who Runs It, And How To Reach Them
The Money: Funding, Valuation, Runway
Who Pays Them, And Who They Are Up Against
Warning Bells
Sources
10 cited sources found
Plus the sections for what you are deciding, which you pick after ordering.
A real finished report, first screen. Opens in a new tab.
Not ready to order yet? Keep this snapshot.
Sends this preview to you once; we won't add you to any list
Purpose of Transaction (Item 4)
EcoR1 Capital, LLC
Scott Platshon, one of EcoR1's employees, resigned from the Issuer's board of directors as of November 16, 2025. Concurrently with his resignation, Mr. Platshon was appointed as the Issuer's Acting Chief Investment Officer. Oleg Nodelman, the manager of EcoR1, is a member of the Issuer's board of directors. The reporting persons acquired the Stock for investment purposes based on their belief that the Issuer's Common Stock, when purchased, was undervalued and represented an attractive investment opportunity. The reporting persons will routinely monitor the Issuer regarding a wide variety of factors that affect their investment considerations, including, current and anticipated future trading prices of the Common Stock and other securities, the Issuer's operations, assets, prospects, financial position, and business development, Issuer's management, Issuer-related competitive and strategic matters, general economic, financial market and industry conditions, and other investment considerations. Depending on their evaluation of various factors, the reporting persons may take such actions regarding their holdings of the Issuer's securities as they deem appropriate in light of circumstances existing from time to time. Such actions may include purchasing additional Common Stock in the open market, through privately negotiated transactions with third parties or otherwise, and selling at any time, in the open market, through privately negotiated transactions with third parties …The first part of Item 4 of the SCHEDULE 13D/A filed 2025-11-19; the filing has the rest
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-07-16 | BlackRock, Inc. | 4.8% | SCHEDULE 13G/A |
| 2025-08-14 | Redmile Group, LLC | 5.6% | SCHEDULE 13G/A |
| 2025-11-14 | Bvf Partners L P | 5.2% | SCHEDULE 13G/A |
| 2025-11-14 | Redmile Group, LLC | 4.9% | SCHEDULE 13G/A |
| 2025-11-19 | EcoR1 Capital, LLC | 30.7% | SCHEDULE 13D/A |
| 2026-02-12 | Morgan Stanley | 3.4% | SCHEDULE 13G/A |
| 2026-02-13 | Rubric Capital Management LP | 7.68% | SCHEDULE 13G/A |
| 2026-04-15 | Perceptive Advisors LLC | 5.4% | SCHEDULE 13G |
| 2026-05-15 | Rubric Capital Management LP | 9.49% | SCHEDULE 13G/A |
Questions about who owns Zymeworks Inc.
Who owns Zymeworks Inc.?
On this page, 4 holders' latest ownership filings report 5% or more of Zymeworks Inc.: EcoR1 Capital, LLC (30.7%, Schedule 13D/A, filed 2025-11-19), Rubric Capital Management LP (9.49%, Schedule 13G/A, filed 2026-05-15), Perceptive Advisors LLC (5.4%, Schedule 13G, filed 2026-04-15) and Bvf Partners L P (5.2%, Schedule 13G/A, filed 2025-11-14).
Who are the largest shareholders of Zymeworks Inc.?
By the share each holder's latest filing reports, the largest holders of Zymeworks Inc. on this page are EcoR1 Capital, LLC (30.7%), Rubric Capital Management LP (9.49%) and Perceptive Advisors LLC (5.4%).
When did EcoR1 Capital, LLC buy into Zymeworks Inc.?
The filings give report dates, not purchase dates. The earliest filing from EcoR1 Capital, LLC on this page is the Schedule 13D/A, filed 2025-11-19, reporting 30.7%. That earliest filing is itself an amendment, which updates an earlier report.
Is this an audit or a full list?
Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 9 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.
Also on the record for Zymeworks Inc.
| Date | Record | Figure | Our page | Source |
|---|---|---|---|---|
| April 1, 2026 | Leadership change: Kristin Stafford appointed, Chief Financial Officer, and 1 more | — | Leadership changes | Source |
Tools for this story
Each opens in a new tab, filled in for Zymeworks Inc.. With no account yet, you sign up free and land on the result.
Where this comes from
Anyone who comes to own more than 5% of a class of a listed company's voting shares has to tell the SEC. A holder who may seek to change or influence the company files Schedule 13D, and has to say in Item 4, "Purpose of Transaction", what it intends to do. A holder with no such intent, such as many index and passive funds, may file the shorter Schedule 13G. Both are amended when the stake changes, including when it falls below 5%.
Every row here is one of those filings, linked to the filing itself. Percentages and share counts are exactly as the holder filed them, for the holder the filing names; an amendment showing a lower figure is shown as filed. Item 4 text is quoted word for word. Where a 13D's Item 4 contains a sentence stating a definite intent to influence the company, that sentence is marked and quoted; the page does not describe the holder or its motives beyond the words it filed. Nothing here is investment advice.