Generation Bio Co.
GBIODelisted Feb 9, 2026- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0001733294
Generation Bio Co. was delisted on Feb 9, 2026; its insiders filed their last Form 4 on Feb 9, 2026; 48 institutions reported holding it in 13F filings for Q4 2025, worth $24.5M in total; no superinvestor held it.
Holders of 5% or more of GBIO
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Generation Bio Co., largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| SymBiosis Capital Partners, LLC | 13G/A | 6.30%421.9K shares | 0.00 ppfrom 6.30% | Nov 14, 20252 filings | Nov 14, 2025 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
20 Schedule 13D and 13G filings on Generation Bio Co., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| May 14, 20264:24 PM ET | Atlas Venture Fund X, L.P.and 5 others | 13G/A | 0.00%0 shares | –Below 5% | Mar 31, 2026 | SEC |
| Feb 17, 202610:26 AM ET | Price T Rowe Associates Inc | 13G/A | 3.10%209.6K shares | −5.50 ppfrom 8.60%Below 5% | Dec 31, 2025 | SEC |
| Feb 12, 20262:14 PM ET | Renaissance Technologies LLCand 1 other | 13G/A | 4.27%287.6K shares | −0.84 ppfrom 5.11%Below 5% | Dec 31, 2025 | SEC |
| Feb 11, 20262:40 PM ET | Baselake Partners, LPand 2 others | 13G/A | 0.00%0 shares | −5.20 ppfrom 5.20%Below 5% | Feb 9, 2026 | SEC |
| Feb 6, 20264:29 PM ET | Baselake Partners, LPand 2 others | 13G | 5.20%350.0K shares | New | Feb 5, 2026 | SEC |
| Nov 14, 20253:19 PM ET | SymBiosis Capital Partners, LLC | 13G/A | 6.30%421.9K shares | 0.00 ppfrom 6.30% | Sep 30, 2025 | SEC |
| Nov 14, 20251:05 PM ET | SymBiosis Capital Partners, LLC | 13G | 6.30%421.9K shares | New | Sep 30, 2025 | SEC |
| Nov 14, 202512:19 PM ET | Price T Rowe Associates Inc | 13G/A | 8.60%576.8K shares | −4.00 ppfrom 12.60% | Sep 30, 2025 | SEC |
| Nov 13, 20252:28 PM ET | Renaissance Technologies LLCand 1 other | 13G | 5.11%344.3K shares | New | Jul 1, 2025 | SEC |
| Aug 14, 20251:07 PM ET | Price T Rowe Associates Inc | 13G/A | 12.60%8.46M shares | – | Jun 30, 2025 | SEC |
| Aug 6, 202512:01 PM ET | FMR LLCand 1 other | 13G/A | 3.50%2.35M shares | −3.40 ppfrom 6.90%Below 5% | Jun 30, 2025 | SEC |
| Jul 17, 20257:54 PM ET | BlackRock, Inc. | 13G/A | 1.70%1.15M shares | –Below 5% | Jun 30, 2025 | SEC |
| Feb 12, 20259:28 AM ET | FMR LLCand 1 other | 13G/A | 6.90%4.63M shares | – | Dec 31, 2024 | SEC |
| Dec 11, 2023 | FMR LLC | 13G/AOld format | – | – | – | SEC |
| Mar 24, 2023 | ModernaTX, Inc. | 13GOld format | – | New | – | SEC |
| Feb 14, 2023 | T. Rowe Price Investment Management, Inc. | 13GOld format | – | New | – | SEC |
| Feb 14, 2023 | BB Biotech AG | 13G/AOld format | – | – | – | SEC |
| Feb 14, 2023 | PFM Health Sciences, LP | 13G/AOld format | – | – | – | SEC |
| Feb 14, 2023 | Price T Rowe Associates Inc | 13G/AOld format | – | – | – | SEC |
| Feb 9, 2023 | Vanguard Group Inc | 13G/AOld format | – | – | – | SEC |
| Feb 9, 2023 | FMR LLC | 13G/AOld format | – | – | – | SEC |
| Feb 1, 20234:54 PM ET | BlackRock Inc. | 13G/AOld format | – | – | – | SEC |
| Feb 1, 2023 | Farallon Capital Partners, L.P. | 13G/AOld format | – | – | – | SEC |
| Sep 6, 2022 | PFM Health Sciences, LP | 13GOld format | – | New | – | SEC |
| Feb 14, 2022 | Price T Rowe Associates Inc | 13G/AOld format | – | – | – | SEC |
| Feb 11, 2022 | Atlas Venture Fund X, L.P. | 13G/AOld format | – | – | – | SEC |
| Feb 11, 2022 | BB Biotech AG | 13G/AOld format | – | – | – | SEC |
| Feb 11, 2022 | Artal International S.C.A. | 13G/AOld format | – | – | – | SEC |
| Feb 10, 2022 | Vanguard Group Inc | 13GOld format | – | New | – | SEC |
| Feb 9, 2022 | FMR LLC | 13G/AOld format | – | – | – | SEC |
| Feb 4, 20224:12 PM ET | BlackRock Inc. | 13GOld format | – | New | – | SEC |
| Feb 3, 2022 | Farallon Capital Management, L.L.C. | 13G/AOld format | – | – | – | SEC |
| Feb 16, 2021 | Atlas Venture Fund X, L.P. | 13GOld format | – | New | – | SEC |
| Feb 16, 2021 | Artal International S.C.A. | 13G/AOld format | – | – | – | SEC |
| Feb 10, 2021 | Price T Rowe Associates Inc | 13G/AOld format | – | – | – | SEC |
| Feb 10, 2021 | Price T Rowe Associates Inc | 13GOld format | – | New | – | SEC |
| Feb 8, 2021 | FMR LLC | 13G/AOld format | – | – | – | SEC |
| Jan 15, 2021 | Farallon Capital Management, L.L.C. | 13G/AOld format | – | – | – | SEC |
| Jan 8, 2021 | BB Biotech AG | 13GOld format | – | New | – | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Generation Bio Co. shares.
No Form 144 notices for Generation Bio Co. are on file.