Skip to main content

Day One Biopharmaceuticals, Inc.

DAWNDelisted
Industry
Pharmaceutical Preparations
SEC CIK
0001845337

Day One Biopharmaceuticals, Inc. was delisted in 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.

Open-market trades, last 90 days

Open-market purchases (P) and sales (S) by Day One Biopharmaceuticals, Inc. insiders, counted by Form 4 filing. Trades with a flagged price and duplicate filings are left out.

Open-market buys
0 filings
Open-market sells
0 filings
Insiders trading
0
Net value
$0
Purchases minus sales

Insider roster

Directors, officers and 10% owners who have filed a Form 4 for Day One Biopharmaceuticals, Inc., current and former, most recent filer first. Last reported holding is the position after the last non-derivative trade in their latest filing.

Insider roster for Day One Biopharmaceuticals, Inc.
NameTitleLast reported holdingLast filingFilings, past year
Blavatnik Len10% Owner0Apr 27, 20261
Access Industries Holdings LLC10% Owner0Apr 27, 20261
Access Industries Management, LLC10% Owner0Apr 27, 20261
AI Day1 LLC10% Owner0Apr 27, 20261
Garland J. ScottDirector–Apr 23, 20262
Ramasastry SairaDirector0Apr 23, 20262
Holles Natalie C.Director0Apr 23, 20262
Nicholson Garry ADirector–Apr 23, 20262
York Charles N IICOO and CFO0Apr 23, 20265
Dable Habib JDirector–Apr 23, 20262
Grossman WilliamDirector–Apr 23, 20262
Vasconcelles MichaelHead of Research and Dev.0Apr 23, 20263
Dubow AdamGen Counsel & Secretary0Apr 23, 20265
Josey John A.Director0Apr 23, 20262
Merendino LaurenChief Commercial Officer0Apr 23, 20265
Bender JeremyCHIEF EXECUTIVE OFFICER0IndirectApr 23, 20266
Blackman Samuel C.HEAD OF R&D1,034,015Dec 12, 20240
Gladstone MichaelDirector766,667IndirectMay 28, 20240
Becker Daniel J.Director–Jun 26, 20230
Grant Papanek JulieDirector330,000IndirectMar 3, 20230
Atlas Venture Fund XI, L.P.10% Owner6,008,534Dec 14, 20220
Canaan XI L.P.10% Owner6,964,301Sep 22, 20220
Canaan Partners XI LLC10% Owner6,964,301Sep 22, 20220
Atlas Venture Opportunity Fund I, L.P.10% Owner793,116Jul 6, 20220
Atlas Venture Associates Opportunity I, L.P.10% Owner766,667Jun 22, 20220
Atlas Venture Associates Opportunity I, LLC10% Owner766,667Jun 22, 20220
Atlas Venture Associates XI, LLC10% Owner766,667Jun 22, 20220
Atlas Venture Associates XI, L.P.10% Owner766,667Jun 22, 20220
Atlas Venture Opportunity Fund II, L.P.10% Owner766,667Jun 22, 20220
Millennium Pharmaceuticals Inc10% Owner6,120,124IndirectDec 9, 20210
Takeda Pharmaceutical Co Ltd10% Owner6,120,124IndirectDec 9, 20210
Takeda Pharmaceuticals U.S.A., Inc.10% Owner6,120,124IndirectDec 9, 20210
Takeda Ventures, Inc.10% Owner6,120,124IndirectDec 9, 20210

Insider trades

Each row adds up one type of transaction in one Form 4 filing. Only open-market purchases (P) and sales (S) are shown by default; use the filters to see grants, option exercises and other codes.

Insider trades
Filed (ET)Trade dateFiling delayInsiderTransactionSharesAvg priceValueHolding changeFlags
Feb 18, 2026 (view filing)Feb 171 dayBender JeremyCHIEF EXECUTIVE OFFICERSSale−15.5K$11.60−$179.3K−7.0%204.6K after
Feb 18, 2026 (view filing)Feb 171 dayMerendino LaurenChief Commercial OfficerSSale−5.81K$11.60−$67.4K−8.8%60.2K after
Feb 18, 2026 (view filing)Feb 171 dayDubow AdamGen Counsel & SecretarySSale−6.39K$11.60−$74.2K−8.1%72.7K after
Feb 18, 2026 (view filing)Feb 171 dayVasconcelles MichaelHead of Research and Dev.SSale−2.73K$11.60−$31.6K−38.3%4.40K after
Feb 18, 2026 (view filing)Feb 171 dayYork Charles N IICOO and CFOSSale−6.07K$11.60−$70.4K−1.9%312.0K after
Nov 18, 2025 (view filing)Nov 171 dayBender JeremyCHIEF EXECUTIVE OFFICERSSale−15.9K$8.91−$141.6K−8.2%177.2K after
Nov 18, 2025 (view filing)Nov 171 dayMerendino LaurenChief Commercial OfficerSSale−3.73K$8.91−$33.2K−6.8%50.8K after
Nov 18, 2025 (view filing)Nov 171 dayDubow AdamGen Counsel & SecretarySSale−4.32K$8.91−$38.5K−6.5%62.6K after
Nov 18, 2025 (view filing)Nov 171 dayYork Charles N IICOO and CFOSSale−4.06K$8.91−$36.2K−1.4%294.7K after
Aug 19, 2025 (view filing)Aug 181 dayYork Charles N IICOO and CFOSSale−4.11K$6.77−$27.8K−1.5%278.0K after
Aug 19, 2025 (view filing)Aug 181 dayDubow AdamGen Counsel & SecretarySSale−4.37K$6.77−$29.6K−7.4%54.9K after
Aug 19, 2025 (view filing)Aug 181 dayBender JeremyCHIEF EXECUTIVE OFFICERSSale−16.1K$6.77−$108.7K−9.1%161.4K after
Aug 19, 2025 (view filing)Aug 181 dayMerendino LaurenChief Commercial OfficerSSale−3.77K$6.77−$25.5K−8.2%41.9K after
May 19, 2025 (view filing)May 163 daysMerendino LaurenChief Commercial OfficerSSale−3.93K$6.26−$24.6K−10.0%35.2K after
May 19, 2025 (view filing)May 163 daysDubow AdamGENERAL COUNSELSSale−4.55K$6.26−$28.5K−8.8%47.1K after
May 19, 2025 (view filing)May 163 daysYork Charles N IICOO, CFO AND SECRETARYSSale−4.28K$6.26−$26.8K−1.6%265.2K after
May 19, 2025 (view filing)May 163 daysBender JeremyCHIEF EXECUTIVE OFFICERSSale−14.0K$6.26−$87.4K−8.7%145.7K after
Feb 21, 2025 (view filing)Feb 183 daysLateYork Charles N IICOO, CFO AND SECRETARYSSale−4.37K$11.96−$52.3K−1.7%252.6K after
Feb 21, 2025 (view filing)Feb 183 daysLateDubow AdamGENERAL COUNSELSSale−4.65K$11.96−$55.6K−10.5%39.6K after
Feb 21, 2025 (view filing)Feb 183 daysLateBender JeremyCHIEF EXECUTIVE OFFICERSSale−12.0K$11.96−$144.1K−8.6%128.0K after
Dec 12, 2024 (view filing)Dec 102 daysBlackman Samuel C.HEAD OF R&DSSale−30.0K$13.31−$399.3K−2.8%1.03M after10b5-1
Nov 19, 2024 (view filing)Nov 181 dayBender JeremyCHIEF EXECUTIVE OFFICERSSale−10.6K$13.21−$139.4K−8.9%108.4K after
Nov 19, 2024 (view filing)Nov 181 dayBlackman Samuel C.HEAD OF R&DSSale−2.21K$13.21−$29.1K−0.2%1.06M after
Nov 19, 2024 (view filing)Nov 181 dayDubow AdamGENERAL COUNSELSSale−3.17K$13.21−$41.8K−9.0%32.2K after
Nov 19, 2024 (view filing)Nov 181 dayYork Charles N IICOO, CFO AND SECRETARYSSale−2.60K$13.21−$34.4K−1.1%240.1K after
Nov 12, 2024 (view filing)Nov 8-114 daysBlackman Samuel C.HEAD OF R&DSSale−28.3K$16.15−$456.2K−2.6%1.06M after2 lots10b5-1
Nov 8, 2024 (view filing)Nov 71 dayBlackman Samuel C.HEAD OF R&DSSale−11.2K$16.03−$180.3K−1.0%1.09M after10b5-1
Nov 4, 2024 (view filing)Oct 314 daysBlackman Samuel C.HEAD OF R&DSSale−500$16.02−$8.01K0.0%1.10M after10b5-1
Sep 12, 2024 (view filing)Sep 102 daysBlackman Samuel C.HEAD OF R&DSSale−30.0K$14.22−$426.6K−2.7%1.10M after10b5-1
Aug 19, 2024 (view filing)Aug 163 daysDubow AdamGENERAL COUNSELSSale−3.20K$14.00−$44.8K−10.6%26.9K after
Aug 19, 2024 (view filing)Aug 163 daysYork Charles N IICOO, CFO AND SECRETARYSSale−2.63K$14.00−$36.9K−1.1%232.5K after
Aug 19, 2024 (view filing)Aug 163 daysBlackman Samuel C.HEAD OF R&DSSale−2.23K$14.00−$31.2K−0.2%1.13M after
Aug 19, 2024 (view filing)Aug 163 daysBender JeremyCHIEF EXECUTIVE OFFICERSSale−10.7K$14.00−$149.5K−9.7%98.9K after
Aug 5, 2024 (view filing)4:01 PM ETAug 14 daysBlavatnik Len and 3 othersOther: Affiliate of 10% OwnerPPurchase+827.6K$14.50+$12.0M–827.6K afterDerivative
Jul 17, 2024 (view filing)Jul 161 dayBlackman Samuel C.HEAD OF R&DSSale−20.0K$16.01−$320.2K−1.8%1.12M after10b5-1
Jun 21, 2024 (view filing)Jun 21Same dayRamasastry SairaDirectorSSale−10.0K$13.19−$131.9K−19.8%40.5K after
Jun 12, 2024 (view filing)Jun 102 daysBlackman Samuel C.HEAD OF R&DSSale−30.0K$12.62−$378.6K−2.6%1.14M after10b5-1
May 17, 2024 (view filing)May 161 dayBender JeremyCHIEF EXECUTIVE OFFICERSSale−7.87K$16.08−$126.6K−1.2%654.7K after
May 17, 2024 (view filing)May 161 dayBlackman Samuel C.HEAD OF R&DSSale−2.27K$16.08−$36.5K−0.2%1.17M after
May 17, 2024 (view filing)May 161 dayYork Charles N IICOO, CFO AND SECRETARYSSale−2.67K$16.08−$43.0K−1.2%224.9K after
May 17, 2024 (view filing)May 161 dayDubow AdamGENERAL COUNSELSSale−3.25K$16.08−$52.3K−13.0%21.7K after
May 14, 2024 (view filing)May 104 daysBlackman Samuel C.HEAD OF R&DSSale−10.0K$16.37−$163.7K−0.9%1.16M after10b5-1
May 3, 2024 (view filing)May 1-32 daysBender JeremyCHIEF EXECUTIVE OFFICERSSale−79.2K$17.88−$1.42M−11.0%642.6K after3 lots10b5-1
May 3, 2024 (view filing)May 1-32 daysYork Charles N IICOO, CFO AND SECRETARYSSale−60.5K$17.88−$1.08M−21.8%217.3K after3 lots10b5-1
Apr 22, 2024 (view filing)Apr 184 daysBlackman Samuel C.HEAD OF R&DSSale−10.0K$16.02−$160.2K−0.8%1.17M after10b5-1
Mar 26, 2024 (view filing)Mar 251 dayBlackman Samuel C.HEAD OF R&DSSale−10.0K$16.01−$160.1K−0.8%1.18M after10b5-1
Mar 13, 2024 (view filing)Mar 112 daysBlackman Samuel C.HEAD OF R&DSSale−30.0K$15.24−$457.2K−2.4%1.19M after10b5-1
Feb 28, 2024 (view filing)Feb 271 dayBlackman Samuel C.HEAD OF R&DSSale−20.0K$16.11−$322.2K−1.6%1.22M after10b5-1
Feb 20, 2024 (view filing)Feb 164 daysDubow AdamGENERAL COUNSELSSale−3.24K$15.25−$49.4K−16.4%16.6K after
Feb 20, 2024 (view filing)Feb 164 daysYork Charles N IICOO, CFO AND SECRETARYSSale−2.67K$15.25−$40.7K−1.0%277.8K after