EcoR1 Capital, LLC: ETON PHARMACEUTICALS INC (ETON): Quarterly 13F Position History
As of Q1 2026, EcoR1 Capital, LLC reported 2,171,938 shares of ETON PHARMACEUTICALS INC (ETON), worth $53.6M and representing 2.3% of its 13F equity book. Quarter-over-quarter share count change: + 141,394 (+7.0%) . The position first appeared in Q3 2024 and has been disclosed across 7 13F-HR filings in Pactolio's tracked window.
- 2,171,938Shares Held (Latest Filing)
- $53.6MReported Market Value (Latest Filing)
- 2.3%Portfolio Weight (% of 13F Equity Book)
- +141,394Quarter-over-Quarter Share Change
- +$19.3MQuarter-over-Quarter Value Change
- 2,171,938Peak Reported Shares (Historical)
Quarterly 13F-HR Disclosure History Source: SEC 13F-HR filings, 7 quarter s
| Quarter | Shares | QoQ Share Change | Share Change (%) | Market Value | Weight | Implied Price |
|---|---|---|---|---|---|---|
| Q1 2026 | 2,171,938 | +141,394 | +7.0% | $53.6M | 2.3% | $24.7 |
| Q4 2025 | 2,030,544 | 0 | — | $34.3M | 1.6% | $16.9 |
| Q3 2025 | 2,030,544 | 0 | — | $44.1M | 2.1% | $21.7 |
| Q2 2025 | 2,030,544 | +91,256 | +4.7% | $28.9M | 1.7% | $14.3 |
| Q1 2025 | 1,939,288 | +109,685 | +6.0% | $25.2M | 1.5% | $13.0 |
| Q4 2024 | 1,829,603 | +1,263,528 | +223.2% | $24.4M | 1.0% | $13.3 |
| Q3 2024 | 566,075 | — | — | $3.4M | 0.1% | $6.0 |
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, not the manager's cost basis. See the full methodology document for the normalization rules.
When did EcoR1 Capital, LLC first disclose a ETON position in 13F-HR filings?
EcoR1 Capital, LLC first reported ETON PHARMACEUTICALS INC (ETON) on its 13F-HR filing for the period ending 2024-09-30 (Q3 2024). The position has appeared on 7 reported quarters within Pactolio's tracked window.
What was EcoR1 Capital, LLC's most recent quarter-over-quarter share-count change in ETON?
Between Q4 2025 and Q1 2026, EcoR1 Capital, LLC added 141,394 shares of ETON (+7.0%), bringing the total reported position to 2,171,938 shares at a market value of $53.6M.
Does the implied price-per-share represent EcoR1 Capital, LLC's cost basis in ETON?
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.