Zymeworks Inc. (ZYME) Ownership
ZYME ownership summary
as of October 18, 2026- Institutions
- 99.5% of shares outstanding
- Insiders
- 1.34% of shares outstanding
- Shares outstanding
- 71.2M
- Float
- 65.8M shares available to trade
- Short interest
- 11.15% 5.3M shares short
- Days to cover
- 6.62 short interest up 7.1% vs prior month
- Institutions 99.48%
- Insiders 1.34%
ZYME top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | EcoR1 Capital, LLC | 32.01% | 23.0M | $574.9M | — | June 30, 2026 |
| 2 | Rubric Capital Management LP | 9.76% | 7.0M | $175.2M | — | June 30, 2026 |
| 3 | BlackRock Inc | 5.92% | 4.3M | $106.4M | −302,858 (−6.7%) | June 30, 2026 |
| 4 | Perceptive Advisors LLC | 5.83% | 4.2M | $104.7M | +672,875 (+19.2%) | June 30, 2026 |
| 5 | Bvf Inc | 5.09% | 3.6M | $91.3M | −85,000 (−2.3%) | June 30, 2026 |
| 6 | Assenagon Asset Management SA | 3.49% | 2.5M | $62.7M | +1.8M (+244.0%) | June 30, 2026 |
| 7 | Morgan Stanley - Brokerage Accounts | 3.11% | 2.2M | $55.8M | −249,308 (−10.1%) | June 30, 2026 |
| 8 | BNP Paribas Investment Partners SA | 2.48% | 1.8M | $44.6M | −126,923 (−6.7%) | June 30, 2026 |
| 9 | Vanguard Capital Management, LLC | 2.17% | 1.6M | $39.0M | −146,582 (−8.6%) | June 30, 2026 |
| 10 | Nextech Invest, Ltd. | 1.55% | 1.1M | $27.9M | — | June 30, 2026 |
| 11 | State Street Corp | 1.52% | 1.1M | $27.2M | +76,439 (+7.6%) | June 30, 2026 |
| 12 | Dimensional Fund Advisors, Inc. | 1.39% | 995K | $24.9M | −144,180 (−12.7%) | June 30, 2026 |
| 13 | Citadel Advisors Llc | 1.27% | 914K | $22.9M | −235,882 (−20.5%) | June 30, 2026 |
| 14 | Delaware Management Holdings Inc | 1.24% | 890K | $22.3M | +889,802 (0.0%) | June 30, 2026 |
| 15 | FMR Inc | 0.98% | 703K | $17.6M | +35,415 (+5.3%) | June 30, 2026 |
| 16 | Geode Capital Management, LLC | 0.96% | 692K | $17.3M | +32,470 (+4.9%) | June 30, 2026 |
| 17 | Prosight Management, LP | 0.94% | 674K | $16.9M | +135,385 (+25.1%) | June 30, 2026 |
| 18 | Qube Research & Technologies | 0.83% | 594K | $14.9M | +81,653 (+15.9%) | June 30, 2026 |
| 19 | Vanguard Portfolio Management, LLC | 0.71% | 510K | $12.8M | +10,157 (+2.0%) | June 30, 2026 |
| 20 | Redmile Group, LLC | 0.69% | 492K | $12.3M | — | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 9 holders added 3.7M shares and 7 cut 1.3M.
ZYME top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | HBM Healthcare Investments AG Ord | 3.52% | 2.5M | $63.1M | — | June 30, 2026 |
| 2 | Vanguard MStar Total Stk Mkt Idx Invest | 2.10% | 1.5M | $37.8M | — | August 31, 2026 |
| 3 | iShares Russell 2000 ETF | 1.65% | 1.2M | $29.7M | −13,696 (−1.1%) | September 30, 2026 |
| 4 | BNP Paribas US Small Cap ClassicC | 1.39% | 998K | $25.0M | −1,911 (−0.2%) | August 31, 2026 |
| 5 | Xtrackers S&P 500 Swap ETF 1C | 1.07% | 769K | $19.2M | −5,671 (−0.7%) | December 31, 2025 |
| 6 | Xtrackers S&P 500 2xLev Dly Swap ETF 1C | 0.88% | 632K | $15.8M | — | December 31, 2025 |
| 7 | iShares Biotechnology ETF | 0.75% | 538K | $13.5M | −4,080 (−0.8%) | September 30, 2026 |
| 8 | Fidelity Small Cap Index | 0.71% | 513K | $12.8M | +3,712 (+0.7%) | July 31, 2026 |
| 9 | BNP Paribas Health Cr Innovtr Cl Cap | 0.71% | 506K | $12.7M | −92 (−0.0%) | August 31, 2026 |
| 10 | MEDICAL BioHealth EUR Acc | 0.65% | 464K | $11.6M | +19,649 (+4.4%) | August 31, 2026 |
| 11 | iShares Russell 2000 Growth ETF | 0.59% | 426K | $10.7M | −539 (−0.1%) | September 30, 2026 |
| 12 | FI Instl US Sm & Md-Cp Cor Eq USD | 0.55% | 392K | $9.8M | +391,658 (0.0%) | August 31, 2026 |
| 13 | Fidelity Small Cap Growth | 0.51% | 369K | $9.2M | — | July 31, 2026 |
| 14 | Vanguard Russell 2000 ETF | 0.37% | 266K | $6.6M | −5,079 (−1.9%) | September 30, 2026 |
| 15 | BlackRock Advantage Small Cap Core Instl | 0.33% | 239K | $6.0M | −3,574 (−1.5%) | August 31, 2026 |
| 16 | Dimensional US Small Cap ETF | 0.26% | 189K | $4.7M | — | September 30, 2026 |
| 17 | Invesco MSCI World ETF | 0.26% | 185K | $4.6M | +185,299 (0.0%) | December 31, 2025 |
| 18 | Fidelity Small Cap Growth K6 | 0.26% | 184K | $4.6M | — | July 31, 2026 |
| 19 | DFA US Small Cap I | 0.25% | 182K | $4.6M | −12,352 (−6.4%) | August 31, 2026 |
| 20 | apo Medical Opportunities R | 0.25% | 181K | $4.5M | — | August 31, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
ZYME insider transactions
latest 10| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-01-12 | Jeffrey T L Smith | Sell | $22.67 | 9,310 | $211,058 |
| 2026-01-12 | Kenneth Galbraith | Sell | $22.67 | 30,424 | $689,712 |
| 2026-01-12 | Mark Hollywood | Sell | $22.67 | 6,120 | $138,740 |
| 2026-01-12 | Paul Andrew Moore | Sell | $22.67 | 9,560 | $216,725 |
| 2026-01-05 | Jeffrey T L Smith | Sell | $25.10 | 10,538 | $264,504 |
| 2026-01-05 | Kenneth Galbraith | Sell | $25.10 | 54,343 | $1.4M |
| 2026-01-05 | Paul Andrew Moore | Sell | $25.10 | 20,110 | $504,761 |
| 2025-12-22 | Kenneth Galbraith | Sell | $27.02 | 47,528 | $1.3M |
| 2025-05-19 | Ecor1 Capital, Llc | Buy | $11.78 | 5,919 | $69,726 |
| 2025-05-15 | Ecor1 Capital, Llc | Buy | $11.43 | 49,502 | $565,808 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
ZYME shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns ZYME
Institutional investors own 99.5% of Zymeworks's shares and insiders 1.34%. The largest holder is EcoR1 Capital, LLC with 32.01% of the shares (23.0M), as of June 30, 2026. Among the top 20 institutions, 9 added shares and 7 reduced their stake in the latest filings. Short interest is 11.15% of the float, or 6.62 days of average trading volume. The share count rose 566.8% since 2015.
Related: ZYME analyst forecast, ZYME key metrics. See the ZYME stock overview for the latest quote and news.
ZYME ownership FAQ
Who owns the most Zymeworks stock?
The largest shareholders of Zymeworks are EcoR1 Capital, LLC (32.01%), Rubric Capital Management LP (9.76%), BlackRock Inc (5.92%), Perceptive Advisors LLC (5.83%), Bvf Inc (5.09%).
What percentage of Zymeworks is owned by institutions?
Institutions hold 99.5% of Zymeworks's shares outstanding; insiders hold 1.34%.
Which funds own Zymeworks?
The largest fund holders of Zymeworks are HBM Healthcare Investments AG Ord (3.52%), Vanguard MStar Total Stk Mkt Idx Invest (2.10%), iShares Russell 2000 ETF (1.65%), BNP Paribas US Small Cap ClassicC (1.39%), Xtrackers S&P 500 Swap ETF 1C (1.07%).
What is Zymeworks's short interest?
5.3M shares of Zymeworks were sold short, 11.15% of the float; at the average daily volume it would take 6.62 days to cover.
Are insiders buying or selling Zymeworks?
Of the latest 10 reported insider transactions in Zymeworks (since May 15, 2025), 2 were purchases and 8 were sales.
How many shares of Zymeworks are outstanding?
Zymeworks has 71.2M shares outstanding, of which 65.8M are in the public float.