Key facts
- EcoR1 Capital, LLC filed SCHEDULE 13G/A for Mereo BioPharma Group plc Ordinary Shares (MREO).
- Disclosed ownership: 8.4%.
- Date of event: 31 Mar 2026.
EcoR1 Capital, LLC - 31 Mar 2026 SCHEDULE 13G/A Report for Mereo BioPharma Group plc Ordinary Shares (MREO)
- Filing Manager
- EcoR1 Capital, LLC
- Reporting Manager
- EcoR1 Capital, LLC
- Symbol
- MREO
- Shares outstanding
- 795,765,179 shares
- Disclosed Ownership
- 66,844,275 shares
- Ownership
- 8.4%
- Form type
- SCHEDULE 13G/A
- Filing time
- 15 May 2026, 14:25:37 UTC
- Date of event
- 31 Mar 2026
- Previous filing
- 09 Jan 2026
- SEC
- View on sec.gov
Key filing fact
EcoR1 Capital, LLC disclosed 8.4% ownership in Mereo BioPharma Group plc Ordinary Shares (MREO) on 31 Mar 2026.
Change
- Previous schedule filing date: 09 Jan 2026.
- Current filing was accepted on 15 May 2026, 14:25.
Research use
- This page explains what this Schedule 13D/13G filing tells you before manager-level rows.
- You can verify ownership claims directly against the original SEC filing.
Evidence
Backed by Schedule 13D/13G
See Original Filing
Beneficial ownership values are sourced from the original SEC Schedule 13D/13G filing.
Reporting persons
Reporting managers (3)
Names, ownership, voting power, signatures, titles, and CIKs as disclosed in this Schedule 13D/G filing.
| Name | Ownership | Shares Owned | sole voting power | shared voting power | Signature | Title | CIK |
|---|---|---|---|---|---|---|---|
| EcoR1 Capital, LLC | 8.4% | 66,844,275 | 0 | 66,844,275 | /s/ Oleg Nodelman | Manager | |
| Oleg Nodelman | 8.4% | 66,844,275 | 0 | 66,844,275 | /s/ Oleg Nodelman | Reporting person | |
| EcoR1 Capital Fund Qualified, L.P. | 7.8% | 62,644,610 | 0 | 62,644,610 | /s/ Oleg Nodelman | Manager of the General Partner, EcoR1 Capital, LLC |
CIK / CUSIP context first