EcoR1 Capital, LLC: ZYMEWORKS INC (ZYME): Quarterly 13F Position History
As of Q2 2026, EcoR1 Capital, LLC reported 22,970,388 shares of ZYMEWORKS INC (ZYME), worth $600.4M and representing 29.8% of its 13F equity book. The position first appeared in Q4 2022 and has been disclosed across 15 13F-HR filings in Pactolio's tracked window.
- 22,970,388Shares Held (Latest Filing)
- $600.4MReported Market Value (Latest Filing)
- 29.8%Portfolio Weight (% of 13F Equity Book)
- 0Quarter-over-Quarter Share Change
- +$25.3MQuarter-over-Quarter Value Change
- 22,970,388Peak Reported Shares (Historical)
Quarterly 13F-HR Disclosure History Source: SEC 13F-HR filings, 15 quarter s
| Quarter | Shares | QoQ Share Change | Share Change (%) | Market Value | Weight | Implied Price |
|---|---|---|---|---|---|---|
| Q2 2026 | 22,970,388 | 0 | – | $600.4M | 29.8% | $26.1 |
| Q1 2026 | 22,970,388 | 0 | – | $575.2M | 24.6% | $25.0 |
| Q4 2025 | 22,970,388 | 0 | – | $604.8M | 27.6% | $26.3 |
| Q3 2025 | 22,970,388 | 0 | – | $392.3M | 18.8% | $17.1 |
| Q2 2025 | 22,970,388 | +5,710,840 | +33.1% | $288.3M | 17.1% | $12.6 |
| Q1 2025 | 17,259,548 | +2,231,469 | +14.8% | $205.6M | 12.2% | $11.9 |
| Q4 2024 | 15,028,079 | +1,590,606 | +11.8% | $220.0M | 8.8% | $14.6 |
| Q3 2024 | 13,437,473 | 0 | – | $168.6M | 5.8% | $12.6 |
| Q2 2024 | 13,437,473 | 0 | – | $114.4M | 3.5% | $8.5 |
| Q1 2024 | 13,437,473 | 0 | – | $141.4M | 3.6% | $10.5 |
| Q4 2023 | 13,437,473 | 0 | – | $139.6M | 3.6% | $10.4 |
| Q3 2023 | 13,437,473 | 0 | – | $85.2M | 2.9% | $6.3 |
| Q2 2023 | 13,437,473 | +3,350,000 | +33.2% | $116.1M | 3.1% | $8.6 |
| Q1 2023 | 10,087,473 | +2,518,900 | +33.3% | $91.2M | 2.9% | $9.0 |
| Q4 2022 | 7,568,573 | – | – | $59.5M | 1.8% | $7.9 |
Methodology & FAQ
How This Position History Is Sourced
Each row is one SEC Form 13F-HR filing disclosing this position. Share count, market value, and reported quarter are taken verbatim from the filing; portfolio weight is recomputed against the same filing's total reported equity book. Implied price-per-share is market value divided by shares, a quarter-end mark rather than the manager's cost basis. See the full methodology document for the normalization rules.
When did EcoR1 Capital, LLC first disclose a ZYME position in 13F-HR filings?
EcoR1 Capital, LLC first reported ZYMEWORKS INC (ZYME) on its 13F-HR filing for the period ending 2022-12-31 (Q4 2022). The position has appeared on 15 reported quarters within Pactolio's tracked window.
What was EcoR1 Capital, LLC's most recent quarter-over-quarter share-count change in ZYME?
EcoR1 Capital, LLC held the same 22,970,388 shares of ZYME between Q1 2026 and Q2 2026, so the reported share count was unchanged quarter-over-quarter.
Does the implied price-per-share represent EcoR1 Capital, LLC's cost basis in ZYME?
No. The implied price-per-share column is the 13F-HR reported market value divided by reported share count on the filing date (end of quarter). It is a quarter-end mark, not a cost basis or transaction price. Use it as a sanity check on the value column, not as an indicator of the manager's entry or exit price.