Day One Biopharmaceuticals, Inc. (DAWN) Insider Ownership

Historic Insider Ownership Trends

As of May 04, 2026, the three largest insider holders of DAWN are Day1 Llc Ai (TenPercentOwner, 12.93Mn shares), Day1 Llc Ai (TenPercentOwner, 12.93Mn shares), Day1 Llc Ai (TenPercentOwner, 12.93Mn shares).

Top Direct Holders

Insider ownership data is derived from the last 60 months of Form 4 SEC filings.
Holder Position Shares (Direct) Shares (Indirect) Report Date
Day1 Llc Ai - 12,929,322 0 20 Oct, 2023
Day1 Llc Ai - 12,929,322 0 20 Oct, 2023
Day1 Llc Ai - 12,929,322 0 20 Oct, 2023
Day1 Llc Ai - 12,929,322 0 20 Oct, 2023
Xi L.P. Canaan - 6,964,301 0 22 Sep, 2022
Xi L.P. Canaan - 6,964,301 0 22 Sep, 2022
Pharmaceutical Co Ltd Takeda - 0 6,120,124 09 Dec, 2021
Venture Fund Xi, L.P. Atlas - 6,008,534 0 14 Dec, 2022
Samuel C. Blackman Head Of Rd 1,034,015 0 12 Dec, 2024
Samuel C. Blackman Chief Medical Officer 0 1,000,000 03 Dec, 2021
Jeremy Bender Chief Executive Officer 0 808,285 26 Nov, 2025
Venture Opportunity Fund I, L.P. Atlas - 793,116 0 06 Jul, 2022
Michael Gladstone - 0 766,667 22 Jun, 2022
Venture Opportunity Fund Ii, L.P. Atlas - 766,667 0 22 Jun, 2022
Michael Gladstone - 0 766,667 22 Jun, 2022
Venture Opportunity Fund Ii, L.P. Atlas - 766,667 0 22 Jun, 2022
Venture Opportunity Fund Ii, L.P. Atlas - 766,667 0 22 Jun, 2022
Venture Opportunity Fund Ii, L.P. Atlas - 766,667 0 22 Jun, 2022
Papanek Julie Grant - 0 463,200 06 Jul, 2022
Julie Papanek Grant - 0 330,000 03 Mar, 2023
Charles N Ii York Coo And Cfo 312,025 0 18 Feb, 2026
Adam Dubow Gen Counsel Secretary 72,694 0 18 Feb, 2026
Lauren Merendino Chief Commercial Officer 60,157 0 18 Feb, 2026
Jeremy Bender Chief Executive Officer 0 18,197 14 Jul, 2025
Michael Vasconcelles Head Of Research And Dev. 4,397 0 18 Feb, 2026

* 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.

Recent Insider Transactions

Detailed insider trading activity based on Form 4 SEC filings.
Download Data
Transaction Date Insider Name Security Class Transaction Type Shares Traded Price Shares Remaining Ownership Code
23 Apr, 2026 Habib J Dable Stock Option (right to buy Common Stock) D 66,660 - 0 D D
23 Apr, 2026 Saira Ramasastry Common Stock D 40,485 - 0 D D
23 Apr, 2026 William Grossman Stock Option (right to buy Common Stock) D 66,660 - 0 D D
23 Apr, 2026 John A. Josey Common Stock D 72,292 - 0 D D
23 Apr, 2026 J. Scott Garland Stock Option (right to buy Common Stock) D 48,072 - 0 D D
23 Apr, 2026 Charles N Ii York Common Stock D 312,025 - 0 D D
23 Apr, 2026 Jeremy Bender Common Stock D 204,643 - 0 D D
23 Apr, 2026 Adam Dubow Common Stock D 72,694 - 0 D D
23 Apr, 2026 Lauren Merendino Common Stock D 60,157 - 0 D D
23 Apr, 2026 Garry A Nicholson Stock Option (right to buy Common Stock) D 33,900 - 0 D D
23 Apr, 2026 Garry A Nicholson Stock Option (right to buy Common Stock) D 33,900 - 0 D D
23 Apr, 2026 Charles N Ii York Common Stock D 312,025 - 0 D D
23 Apr, 2026 John A. Josey Common Stock D 72,292 - 0 D D
23 Apr, 2026 Lauren Merendino Common Stock D 60,157 - 0 D D
23 Apr, 2026 Saira Ramasastry Common Stock D 40,485 - 0 D D
23 Apr, 2026 Michael Vasconcelles Common Stock D 4,397 - 0 D D
23 Apr, 2026 Habib J Dable Stock Option (right to buy Common Stock) D 66,660 - 0 D D
23 Apr, 2026 William Grossman Stock Option (right to buy Common Stock) D 66,660 - 0 D D
23 Apr, 2026 Natalie C. Holles Common Stock D 57,310 - 0 D D
23 Apr, 2026 Natalie C. Holles Common Stock D 57,310 - 0 D D