Data spanning the past 90 days through January 10, 2026 reveals that Day One Biopharmaceuticals's three principal insider shareholders consist of TenPercentOwner Day1 Llc Ai (12.93Mn shares), TenPercentOwner Xi L.P. Canaan (6.96Mn shares), TenPercentOwner Pharmaceutical Co Ltd Takeda (6.12Mn shares).
| Holder | Position | Shares | Report Date |
|---|---|---|---|
| Day1 Llc Ai | 12,929,322 | 20 Oct, 2023 | |
| Xi L.P. Canaan | 6,964,301 | 22 Sep, 2022 | |
| Pharmaceutical Co Ltd Takeda | 6,120,124 | 09 Dec, 2021 | |
| Venture Fund Xi, L.P. Atlas | 6,008,534 | 14 Dec, 2022 | |
| Samuel C. Blackman | Head Of R&D | 2,034,015 | 12 Dec, 2024 |
| Venture Opportunity Fund I, L.P. Atlas | 793,116 | 06 Jul, 2022 | |
| Venture Opportunity Fund Ii, L.P. Atlas | 766,667 | 22 Jun, 2022 | |
| Michael Gladstone | 766,667 | 22 Jun, 2022 | |
| Julie Papanek Grant | 330,000 | 03 Mar, 2023 | |
| Charles N Ii York | Coo And Cfo | 294,715 | 18 Nov, 2025 |
| Jeremy Bender | Chief Executive Officer | 177,165 | 18 Nov, 2025 |
| John A. Josey | 72,292 | 01 Jun, 2021 | |
| Adam Dubow | Gen Counsel & Secretary | 62,626 | 18 Nov, 2025 |
| Lauren Merendino | Chief Commercial Officer | 50,809 | 18 Nov, 2025 |
| Saira Ramasastry | 40,485 | 21 Jun, 2024 | |
| Daniel J. Becker | 5,000 | 01 Jun, 2021 |
* Please note that the shares above only reflect shares from the fund portfolio and the institutional portfolio. Shares from the personal portfolio are excluded from this Institutional Ownership Page. See these insiders' latest transactions here on Insider Page.
| Transaction Date | Insider Name | Security Class | Transaction Type | Shares Traded | Price | Shares Remaining | Ownership | Code |
|---|---|---|---|---|---|---|---|---|
| 25 Nov, 2025 | Jeremy Bender | Common Stock | D | 300,000 | $0.00 | 808,285 | I | G |
| 25 Nov, 2025 | Jeremy Bender | Common Stock | A | 300,000 | $0.00 | 300,000 | I | G |
| 25 Nov, 2025 | Jeremy Bender | Common Stock | D | 7,225 | $0.00 | 7,225 | I | G |
| 25 Nov, 2025 | Jeremy Bender | Common Stock | D | 7,225 | $0.00 | 0 | I | G |
| 25 Nov, 2025 | Jeremy Bender | Common Stock | D | 300,000 | $0.00 | 1,108,285 | I | G |
| 25 Nov, 2025 | Jeremy Bender | Common Stock | A | 300,000 | $0.00 | 300,000 | I | G |
| 17 Nov, 2025 | Charles N Ii York | Common Stock | D | 4,062 | $8.91 | 294,715 | D | S |
| 17 Nov, 2025 | Adam Dubow | Common Stock | D | 4,319 | $8.91 | 62,626 | D | S |
| 17 Nov, 2025 | Lauren Merendino | Common Stock | D | 3,726 | $8.91 | 50,809 | D | S |
| 17 Nov, 2025 | Jeremy Bender | Common Stock | D | 15,894 | $8.91 | 177,165 | D | S |
| 15 Nov, 2025 | Charles N Ii York | Common Stock | A | 6,625 | - | 292,152 | D | M |
| 15 Nov, 2025 | Charles N Ii York | Common Stock | A | 1,375 | - | 283,277 | D | M |
| 15 Nov, 2025 | Charles N Ii York | Common Stock | A | 6,625 | - | 298,777 | D | M |
| 15 Nov, 2025 | Charles N Ii York | Common Stock | A | 2,250 | - | 285,527 | D | M |
| 15 Nov, 2025 | Adam Dubow | Common Stock | A | 3,687 | - | 63,258 | D | M |
| 15 Nov, 2025 | Adam Dubow | Common Stock | A | 1,750 | - | 59,571 | D | M |
| 15 Nov, 2025 | Adam Dubow | Common Stock | A | 2,963 | - | 57,821 | D | M |
| 15 Nov, 2025 | Adam Dubow | Common Stock | A | 3,687 | - | 66,945 | D | M |
| 15 Nov, 2025 | Lauren Merendino | Common Stock | A | 3,687 | - | 54,535 | D | M |
| 15 Nov, 2025 | Lauren Merendino | Common Stock | A | 3,162 | - | 47,161 | D | M |