Day One Biopharmaceuticals, Inc.
DAWNDelisted Apr 23, 2026- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0001845337
Day One Biopharmaceuticals, Inc. was delisted on Apr 23, 2026; its insiders filed their last Form 4 on Apr 27, 2026; 208 institutions reported holding it in 13F filings for Q1 2026, worth $1.85B in total; Soros Fund Management was the only superinvestor holding it.
Holders of 5% or more of DAWN
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Day One Biopharmaceuticals, Inc., largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| BlackRock, Inc. | 13G | 5.80%5.85M shares | +1.10 ppfrom 4.70% | Apr 28, 20252 filings | Jul 17, 2025 | SEC |
| Glazer Capital, LLC | 13G | 5.40%5.62M shares | New | Mar 19, 20261 filing | Mar 19, 2026 | 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
16 Schedule 13D and 13G filings on Day One Biopharmaceuticals, Inc., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| May 15, 20265:02 PM ET | Vestal Point Capital, LPand 1 other | 13G/A | 0.00%0 shares | −5.10 ppfrom 5.10%Below 5% | Mar 31, 2026 | SEC |
| May 14, 20264:19 PM ET | Atlas Venture Fund XI, L.P.and 8 others | 13G/A | 0.00%0 shares | –Below 5% | Mar 31, 2026 | SEC |
| Apr 27, 20265:55 PM ET | AI Day1 LLCand 3 others | 13D/A | 0.00%0 shares | −12.52 ppfrom 12.52%Below 5% | Apr 23, 2026 | SEC |
| Apr 13, 20265:06 PM ET | AI Day1 LLCand 3 others | 13D/A | 12.52%12.9M shares | – | Apr 9, 2026 | SEC |
| Apr 7, 20261:22 PM ET | FMR LLCand 1 other | 13G/A | 0.00%23.6K shares | −5.60 ppfrom 5.60%Below 5% | Mar 31, 2026 | SEC |
| Mar 26, 20265:42 PM ET | Vanguard Group Inc | 13G/A | 0.00%0 shares | –Below 5% | Mar 13, 2026 | SEC |
| Mar 19, 20264:46 PM ET | Glazer Capital, LLCand 1 other | 13G | 5.40%5.62M shares | New | Mar 12, 2026 | SEC |
| Feb 17, 20264:06 PM ET | Vestal Point Capital, LPand 1 other | 13G | 5.10%5.20M shares | New | Dec 31, 2025 | SEC |
| Feb 5, 20261:20 PM ET | FMR LLCand 1 other | 13G/A | 5.60%5.72M shares | −4.30 ppfrom 9.90% | Dec 31, 2025 | SEC |
| Nov 5, 202511:30 AM ET | FMR LLCand 1 other | 13G/A | 9.90%10.1M shares | −1.30 ppfrom 11.20% | Sep 30, 2025 | SEC |
| Aug 14, 20256:00 PM ET | Ra Capital Management, L.P.and 3 others | 13G/A | 0.00%0 shares | −5.70 ppfrom 5.70%Below 5% | Jun 30, 2025 | SEC |
| Aug 6, 202511:56 AM ET | FMR LLCand 1 other | 13G/A | 11.20%11.3M shares | −1.60 ppfrom 12.80% | Jun 30, 2025 | SEC |
| Jul 17, 20257:54 PM ET | BlackRock, Inc. | 13G | 5.80%5.85M shares | +1.10 ppfrom 4.70% | Jun 30, 2025 | SEC |
| Apr 28, 20255:45 PM ET | BlackRock, Inc. | 13G/A | 4.70%4.81M shares | –Below 5% | Mar 31, 2025 | SEC |
| Feb 14, 20256:31 PM ET | Ra Capital Management, L.P.and 3 others | 13G/A | 5.70%5.76M shares | – | Dec 31, 2024 | SEC |
| Feb 12, 20259:28 AM ET | FMR LLCand 1 other | 13G/A | 12.80%12.9M shares | – | Dec 31, 2024 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Day One Biopharmaceuticals, Inc. shares.
No Form 144 notices for Day One Biopharmaceuticals, Inc. are on file.