Day One Biopharmaceuticals, Inc. has 13 Schedule 13D or 13G filings on record since 2025-07-17. 2 holders' latest filing reports 5% or more of common stock, par value $0.0001 per share. Each figure below is the holder's own, as filed, with the filing linked.
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| BlackRock, Inc. | 5.8% | 5,849,917 | SCHEDULE 13G, 2025-07-17 | 2025-06-30 |
| Glazer Capital, LLC | 5.4% | 5,615,390 | SCHEDULE 13G, 2026-03-19 | 2026-03-12 |
| Fmr LLC | 0% | 23,640 | SCHEDULE 13G/A, 2026-04-07 | 2026-03-31 |
| RA Capital Management, L.P. | 0% | 0 | SCHEDULE 13G/A, 2025-08-14 | 2025-06-30 |
| Vestal Point Capital, LP | 0% | 0 | SCHEDULE 13G/A, 2026-05-15 | 2026-03-31 |
| The Vanguard Group | 0% | 0 | SCHEDULE 13G/A, 2026-03-26 | 2026-03-13 |
| AI Day1 LLC | 0% | 0 | SCHEDULE 13D/A, 2026-04-27 | 2026-04-23 |
| Atlas Venture Fund XI, L.P. | 0% | 0 | SCHEDULE 13G/A, 2026-05-14 | 2026-03-31 |
Purpose of Transaction (Item 4)
AI Day1 LLC
The disclosure in Item 4 is hereby amended and supplemented by adding the following at the end thereof: On April 9, 2026, AI Day1 tendered all of its shares of Common Stock pursuant to the tender offer by Servier Detroit Inc. ("Purchaser") to purchase all of the issued and outstanding shares of Common Stock for $21.50 per share in cash, upon the terms and subject to the conditions described in the Offer to Purchase and related Letter of Transmittal filed with the SEC on Schedule TO on March 26, 2026 (the "Tender Offer"). Such shares were accepted by the Purchaser on April 23, 2026. On April 23, 2026, in connection with the consummation of the merger, each pre-funded warrant held by AI Day1 to purchase Common Stock was converted into the right to receive $21.4999 per warrant in cash.Item 4 of the SCHEDULE 13D/A filed 2026-04-27
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-07-17 | BlackRock, Inc. | 5.8% | SCHEDULE 13G |
| 2025-08-06 | Fmr LLC | 11.2% | SCHEDULE 13G/A |
| 2025-08-14 | RA Capital Management, L.P. | 0% | SCHEDULE 13G/A |
| 2025-11-05 | Fmr LLC | 9.9% | SCHEDULE 13G/A |
| 2026-02-05 | Fmr LLC | 5.6% | SCHEDULE 13G/A |
| 2026-02-17 | Vestal Point Capital, LP | 5.1% | SCHEDULE 13G |
| 2026-03-19 | Glazer Capital, LLC | 5.4% | SCHEDULE 13G |
| 2026-03-26 | The Vanguard Group | 0% | SCHEDULE 13G/A |
| 2026-04-07 | Fmr LLC | 0% | SCHEDULE 13G/A |
| 2026-04-13 | AI Day1 LLC | 12.52% | SCHEDULE 13D/A |
| 2026-04-27 | AI Day1 LLC | 0% | SCHEDULE 13D/A |
| 2026-05-14 | Atlas Venture Fund XI, L.P. | 0% | SCHEDULE 13G/A |
| 2026-05-15 | Vestal Point Capital, LP | 0% | SCHEDULE 13G/A |
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Where this comes from
Anyone who comes to own more than 5% of a class of a listed company's voting shares has to tell the SEC. A holder who may seek to change or influence the company files Schedule 13D, and has to say in Item 4, "Purpose of Transaction", what it intends to do. A holder with no such intent, such as many index and passive funds, may file the shorter Schedule 13G. Both are amended when the stake changes, including when it falls below 5%.
Every row here is one of those filings, linked to the filing itself. Percentages and share counts are exactly as the holder filed them, for the holder the filing names; an amendment showing a lower figure is shown as filed. Item 4 text is quoted word for word. Where a 13D's Item 4 contains a sentence stating a definite intent to influence the company, that sentence is marked and quoted; the page does not describe the holder or its motives beyond the words it filed. Nothing here is investment advice.